The Tannoy T300 is - 6db @ 16K at 90 degrees.
It completely depends upon the design of the waveguide.
But again, in many situations a narrower HF pattern is actually preferable. Plus, one can always use an array, which is better for wide coverage than any wide dispersion pattern, anyway. (though of course, more costly.)
Compact, an alternative to the classic setup?
Hi johnnyjo,
I just read your post, not shure you get what you want here.
If your looking for Hifidelity, but also DIY AND compact, WHY not look at the following. I've designed and build this type of PA, fit's in the boot of your car.
1 - VERY easy to build,
2 - Affordable, tops are 130 euro on material each (prices in the Netherlands that is)
3 - Very audible, superb vocals
4 - Almost "invisible", VERY small footprint.
5 - Super directivity vertical, wide spread horizontal
6 - Near HiFi
What it is?
Low end a bass reflex, (tapped horn or any other device with a good punch possible, BUT more complex design and build).
Hi end is a Column with 4" driver, full range.
Eighter a Class D digital amp with build in DSP, or a stereo amp with separate DSP.
For a utility holding about 200 people, I would suggest (have installed various PA's of this type):
Low end: 2 x 15" bass reflex, tuned at around 30 - 35 Hz, PLACED STACKED IN A CORNER, driven MONO. Why in the corner, simple, gives you an extra 6 dB in this setup, that a lot LESS amp power required. Why stacked, NO phasing and cancelation issues. With a decent driver, your looking at 75 - 100 liters each.
High end: 2 columns with 4 x 4" full range drivers each. Various suppliers available, like Faital Pro. Columns are 4 liters each, placed on a pole. THE big advantage of a Column is LONG throw and wide dispersion. Because they "carry" sound much further, the complete room will be covered. NO spill against floor or ceiling. Tune them as 4 closed compartments to roll of around 180 Hz, which for a Faital Pro 4Fe32 would be 0,9 liters each. They are a real match for your "full range", from 180 Hz upwards. The Faital goes to 18KHz easily and feels happy with loads of power. I run 400 watts per Column, crossed at 180 Hz.
I would NEVER use a full range on a pole, like half the world does (god knows why), the low end is not supported properly and will drop in SPL very fast. Half way the room, there is hardly any low end left, resulting in the need to cranck up the volume, which ISN't the real cure. You will end up in distortion and blown drivers / crap sound. WAY to loud nearby, NO low end half way the room.
Crown Class D XLS 2502, which holds a DSP AND band-pass functions. Cross-over at 180 Hz 24 dB. If you want stereo, use 1 XLS bridged band pass 30 - 180 Hz for the low end and 1 XLS 2502 stereo high pass 180 Hz upwards.
Maybe use a DBX DSP, like the drive rack PA2. You can adjust filters any way you like including tuning it to your room.
I use this setup as a PA, sold to various bands (rock a billy, Fusion, Jazz, Pop / Rock) with very satisfied musicians and happy customers of these bands. Good sound quality, LOUD, but not irritating loud, pleasant to listen for hours.
DIY?. This system is just very simple to build. 18 mm birch multi ply for low end, 12 mm birch for the tops.
Added a few pictures, so you get an idea.
https://www.facebook.com/WAEinfo/?pnref=lhc
picture upload doesn't work for some reason, see Facebook link (in Dutch, sorry ;-) )
Hi johnnyjo,
I just read your post, not shure you get what you want here.
If your looking for Hifidelity, but also DIY AND compact, WHY not look at the following. I've designed and build this type of PA, fit's in the boot of your car.
1 - VERY easy to build,
2 - Affordable, tops are 130 euro on material each (prices in the Netherlands that is)
3 - Very audible, superb vocals
4 - Almost "invisible", VERY small footprint.
5 - Super directivity vertical, wide spread horizontal
6 - Near HiFi
What it is?
Low end a bass reflex, (tapped horn or any other device with a good punch possible, BUT more complex design and build).
Hi end is a Column with 4" driver, full range.
Eighter a Class D digital amp with build in DSP, or a stereo amp with separate DSP.
For a utility holding about 200 people, I would suggest (have installed various PA's of this type):
Low end: 2 x 15" bass reflex, tuned at around 30 - 35 Hz, PLACED STACKED IN A CORNER, driven MONO. Why in the corner, simple, gives you an extra 6 dB in this setup, that a lot LESS amp power required. Why stacked, NO phasing and cancelation issues. With a decent driver, your looking at 75 - 100 liters each.
High end: 2 columns with 4 x 4" full range drivers each. Various suppliers available, like Faital Pro. Columns are 4 liters each, placed on a pole. THE big advantage of a Column is LONG throw and wide dispersion. Because they "carry" sound much further, the complete room will be covered. NO spill against floor or ceiling. Tune them as 4 closed compartments to roll of around 180 Hz, which for a Faital Pro 4Fe32 would be 0,9 liters each. They are a real match for your "full range", from 180 Hz upwards. The Faital goes to 18KHz easily and feels happy with loads of power. I run 400 watts per Column, crossed at 180 Hz.
I would NEVER use a full range on a pole, like half the world does (god knows why), the low end is not supported properly and will drop in SPL very fast. Half way the room, there is hardly any low end left, resulting in the need to cranck up the volume, which ISN't the real cure. You will end up in distortion and blown drivers / crap sound. WAY to loud nearby, NO low end half way the room.
Crown Class D XLS 2502, which holds a DSP AND band-pass functions. Cross-over at 180 Hz 24 dB. If you want stereo, use 1 XLS bridged band pass 30 - 180 Hz for the low end and 1 XLS 2502 stereo high pass 180 Hz upwards.
Maybe use a DBX DSP, like the drive rack PA2. You can adjust filters any way you like including tuning it to your room.
I use this setup as a PA, sold to various bands (rock a billy, Fusion, Jazz, Pop / Rock) with very satisfied musicians and happy customers of these bands. Good sound quality, LOUD, but not irritating loud, pleasant to listen for hours.
DIY?. This system is just very simple to build. 18 mm birch multi ply for low end, 12 mm birch for the tops.
Added a few pictures, so you get an idea.
https://www.facebook.com/WAEinfo/?pnref=lhc
picture upload doesn't work for some reason, see Facebook link (in Dutch, sorry ;-) )
Last edited:
picture
picture of high end top (4x 4")
Picture 1 - the top cabinet (11 x 44 x 15 cm)
Picture 2 - PA measured during live gig
Picture 3 - Rock a Billy outdoor (4x top cabinet @ 2,5 kW) and 2 15" subs under the small stage (3 kW). One top cabinet is turned towards the band as a monitor, NO feedback!).
kind regards,
Frans
picture of high end top (4x 4")
Picture 1 - the top cabinet (11 x 44 x 15 cm)
Picture 2 - PA measured during live gig
Picture 3 - Rock a Billy outdoor (4x top cabinet @ 2,5 kW) and 2 15" subs under the small stage (3 kW). One top cabinet is turned towards the band as a monitor, NO feedback!).
kind regards,
Frans
Attachments
Price is also relatively low for those drivers 🙂
Probably indestructible at high frequencies also.
Off axis once you get ~4KHz starts to drop. Do you equalise up at all? I know it's all a bit subjective with a live band at high frequency.
Probably indestructible at high frequencies also.
Off axis once you get ~4KHz starts to drop. Do you equalise up at all? I know it's all a bit subjective with a live band at high frequency.
Hi Dogshome,
Yes, price is a very positive here. The first time I had this idea of a portable PA (looking at HK audio) I noticed they use a 3,5" driver. I thought to cranck it up a little and use 4". The Faitals are almost HiFi. Because of the low cost, I just went for 4 cabinets and during the first test, could not believe my ears. I started with a small amp, but could not see any cone motion at serious levels as also predicted by Bass Box Pro. They should do 4 mm max at 100 watts per driver. I ended up at 400 watts per cabinet, where distortion came into play. Because they are in a sealed enclosure for each driver, tuned at 180 Hz, this seems inevitable in the end to happen.
My first gig was with a Rock a Billy band in what they told me was a small pub. I took 2 tops and 2x 12 inch bass reflex subs (placed in corner), with a Crown XLS 2500 and a DBX DSP, set at 140 Hz cross over 24 dB.
It turned out to be a narrow but very deep (40 meters) pub which held 400 people, not really small. I just went for it, there was no going back to get more stuff, and my tests were positive.
Because of the Column construction these tops vertically beam very far before SPL drops. So the band, specially vocals was clear EVERY were in the Pub. The band was over the moon and bought a set (my first portable PA sell).
When after the gig, I wanted to put the PA back in my car, I noticed a serious smell from the Tops. The kind of melting voice coil smell, when burning a driver. The wood and speaker grill were HOT. The speakers were almost glowing in the dark. I did not understand where this was coming from. On paper this should work. After first thought to put bass reflex ports in the top, just for cooling purpose, I give myself some time to think. Testing the speaker showed they were ALL OK, after being overloaded for 3 hours, so not expensive but VERY solid!!
I had made, as it turned out, a very stupid error. Tuning 4" speakers to roll of @ 180Hz and then set the cross over to 140 Hz, duhhh😱😱😱 During the gig I was missing some low-mid and try to add by adding some EQ at that point. NOTHING noticeable happend, off course. The speaker just CAN NOT produce 140 to 180 Hz, so there is no use loading it.
I asked a friend to measure the cabinets, and just as expected 8 - 12 kHz is a bit of a +4 dB peak area. So, YES I Eq, but only DROP -4 dB around that area, NO EQ up at any other point.
The roll of now from 8 kHz flat to 18 kHz -3 dB sounds nice crispy for Hi-Hatt / Symbals / etc.
Although they seem to drop a bit off axis, again the 4 drivers tight fit against each other add some dB off axis in the horizontal area and beam very tight in the vertical. This helps preventing reflections on ground and ceiling, so although on paper you are right, in practice I just tow in 20 degree to create a nice sound scape and make up for the small drop off.
KEEP IT SIMPLE is my moto and EQ'ing is not always easy at live gigs.
I think THE biggest advantage of this type of top cabinet, apart from install connect and play in 5 minutes (they weigh 3,5 Kilo each, which is a laugh), is the VERY nice sound they create from 180 - to 8 kHz, where ALL important frequencies from vocals, drum, guitar, keyboard, symbals, sax, trumpets, YOU name it. VERY audible.
Bottom line, NO I don't do additional EQ'ing at any gig, just the fixed EQ at 8 - 12 kHz in the DBX DSP. They are also monitors, because they are intended to be placed BEHIND the band. Place them Above the Microfoon hight and NO feedback occurs.
I got hooked on these little basterds and every where I come, people are amazed. "HEY sonny, where is the PA??" "Your standing on it..", is my return joke. I mean, 3,5 kilo's, 44 x 11 x 15 cm is not really big, is it? 😀
That's why I keep saying, WHY drags big boxes on top of a Pole, even while it just does not add up. I mean, 15" and a 1" with a horn and a (usually cheap cross-over) is a ideal setup for average to crap sound. The 15" is good in the low / low-mid area (better than the 4") but they are a not very nice to listen to from say 500 Hz upwards. They sound muddy for vocals and lack sweet presence. Then the 1" with horn takes over, blasting away. The cross-over area is a disaster, 15 - 20 cm distance between voice-coils at least is THE receipt for phase problems. Directivity of the 15" is non existent but starts to kick in just below cross over. This results a big SPL drop off, starting to happen at 3 meters away. Then musicians and sound technicians start adding volume to get "more" at a longer distance from the stage, ending up in way to loud at the stage and most of the time, distortion. SO why drag 40 kilo's per cabinet that does not give what you want.
Give it a go, I would say. A 4" loaded column combined with a solid sub can do miracles. It even seems cool for the audience to see these puppy boxes blasting away with a very nice sound stage. That's what I keep getting as very positive comments.
kind regards,
Frans
Yes, price is a very positive here. The first time I had this idea of a portable PA (looking at HK audio) I noticed they use a 3,5" driver. I thought to cranck it up a little and use 4". The Faitals are almost HiFi. Because of the low cost, I just went for 4 cabinets and during the first test, could not believe my ears. I started with a small amp, but could not see any cone motion at serious levels as also predicted by Bass Box Pro. They should do 4 mm max at 100 watts per driver. I ended up at 400 watts per cabinet, where distortion came into play. Because they are in a sealed enclosure for each driver, tuned at 180 Hz, this seems inevitable in the end to happen.
My first gig was with a Rock a Billy band in what they told me was a small pub. I took 2 tops and 2x 12 inch bass reflex subs (placed in corner), with a Crown XLS 2500 and a DBX DSP, set at 140 Hz cross over 24 dB.
It turned out to be a narrow but very deep (40 meters) pub which held 400 people, not really small. I just went for it, there was no going back to get more stuff, and my tests were positive.
Because of the Column construction these tops vertically beam very far before SPL drops. So the band, specially vocals was clear EVERY were in the Pub. The band was over the moon and bought a set (my first portable PA sell).
When after the gig, I wanted to put the PA back in my car, I noticed a serious smell from the Tops. The kind of melting voice coil smell, when burning a driver. The wood and speaker grill were HOT. The speakers were almost glowing in the dark. I did not understand where this was coming from. On paper this should work. After first thought to put bass reflex ports in the top, just for cooling purpose, I give myself some time to think. Testing the speaker showed they were ALL OK, after being overloaded for 3 hours, so not expensive but VERY solid!!
I had made, as it turned out, a very stupid error. Tuning 4" speakers to roll of @ 180Hz and then set the cross over to 140 Hz, duhhh😱😱😱 During the gig I was missing some low-mid and try to add by adding some EQ at that point. NOTHING noticeable happend, off course. The speaker just CAN NOT produce 140 to 180 Hz, so there is no use loading it.
I asked a friend to measure the cabinets, and just as expected 8 - 12 kHz is a bit of a +4 dB peak area. So, YES I Eq, but only DROP -4 dB around that area, NO EQ up at any other point.
The roll of now from 8 kHz flat to 18 kHz -3 dB sounds nice crispy for Hi-Hatt / Symbals / etc.
Although they seem to drop a bit off axis, again the 4 drivers tight fit against each other add some dB off axis in the horizontal area and beam very tight in the vertical. This helps preventing reflections on ground and ceiling, so although on paper you are right, in practice I just tow in 20 degree to create a nice sound scape and make up for the small drop off.
KEEP IT SIMPLE is my moto and EQ'ing is not always easy at live gigs.
I think THE biggest advantage of this type of top cabinet, apart from install connect and play in 5 minutes (they weigh 3,5 Kilo each, which is a laugh), is the VERY nice sound they create from 180 - to 8 kHz, where ALL important frequencies from vocals, drum, guitar, keyboard, symbals, sax, trumpets, YOU name it. VERY audible.
Bottom line, NO I don't do additional EQ'ing at any gig, just the fixed EQ at 8 - 12 kHz in the DBX DSP. They are also monitors, because they are intended to be placed BEHIND the band. Place them Above the Microfoon hight and NO feedback occurs.
I got hooked on these little basterds and every where I come, people are amazed. "HEY sonny, where is the PA??" "Your standing on it..", is my return joke. I mean, 3,5 kilo's, 44 x 11 x 15 cm is not really big, is it? 😀
That's why I keep saying, WHY drags big boxes on top of a Pole, even while it just does not add up. I mean, 15" and a 1" with a horn and a (usually cheap cross-over) is a ideal setup for average to crap sound. The 15" is good in the low / low-mid area (better than the 4") but they are a not very nice to listen to from say 500 Hz upwards. They sound muddy for vocals and lack sweet presence. Then the 1" with horn takes over, blasting away. The cross-over area is a disaster, 15 - 20 cm distance between voice-coils at least is THE receipt for phase problems. Directivity of the 15" is non existent but starts to kick in just below cross over. This results a big SPL drop off, starting to happen at 3 meters away. Then musicians and sound technicians start adding volume to get "more" at a longer distance from the stage, ending up in way to loud at the stage and most of the time, distortion. SO why drag 40 kilo's per cabinet that does not give what you want.
Give it a go, I would say. A 4" loaded column combined with a solid sub can do miracles. It even seems cool for the audience to see these puppy boxes blasting away with a very nice sound stage. That's what I keep getting as very positive comments.
kind regards,
Frans
A nice setup.
I'm using "cheapo-wave" style speakers with fairly complex passive crossovers and a separate sub at home. I like the horn tweeters and the imaging/dynamic range they give combined with 10" mids.
I get it with the stacked 4" drivers and dynamic crossovers though 😎
Keb' Mo' That's alright makes the room jump here 😀
I'm using "cheapo-wave" style speakers with fairly complex passive crossovers and a separate sub at home. I like the horn tweeters and the imaging/dynamic range they give combined with 10" mids.
I get it with the stacked 4" drivers and dynamic crossovers though 😎
Keb' Mo' That's alright makes the room jump here 😀
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Wish the RCF Evox series was available when I was building a rig, they look professional and get great reviews.
I still like my old RCF Art310's as getting the sound right on my DIY attempts was a pain and I was not thrilled with the finish. Hope you have better luck than I did.
I still like my old RCF Art310's as getting the sound right on my DIY attempts was a pain and I was not thrilled with the finish. Hope you have better luck than I did.
Hi wae,
This looks good. Very compact and I'm trying to do something similar. I'm a beginner
Can I ask you about this:
"They should do 4 mm max at 100 watts per driver. I ended up at 400 watts per cabinet, where distortion came into play. Because they are in a sealed enclosure for each driver, tuned at 180 Hz, this seems inevitable in the end to happen"
How did you calculate the 180Hz figure for tuning the speakers ?
Also from the spec sheet the 4FE35 XMax parameter is 2.73mm Why is it ok to operate at 4mm excursion? Will it not distort above XMax??
Lastly what internal materials did you use for damping/reflections
Thanks for a great post
Ed
This looks good. Very compact and I'm trying to do something similar. I'm a beginner
Can I ask you about this:
"They should do 4 mm max at 100 watts per driver. I ended up at 400 watts per cabinet, where distortion came into play. Because they are in a sealed enclosure for each driver, tuned at 180 Hz, this seems inevitable in the end to happen"
How did you calculate the 180Hz figure for tuning the speakers ?
Also from the spec sheet the 4FE35 XMax parameter is 2.73mm Why is it ok to operate at 4mm excursion? Will it not distort above XMax??
Lastly what internal materials did you use for damping/reflections
Thanks for a great post
Ed
Hi Wakko59,
Nice to hear from you. As to your questions;
I use bass box Pro to design my speakers, both bass reflex and closed cabinet. When you enter the Thiele & Small parameters into bass box Pro and specify a closed box, it tells you where the optimum for this speaker is. For the Faital's, the speaker starts rolling off around 180 Hz with a volume of about 1 liter (0,9 to be exact doing this out of my head). SO, we could go higher which is still OK for the driver, BUT other factors come into play here. I had set myself some design rules;
- Small box
- 2-way portable PA top cabinet
- NO critical instruments and human voice around the cross-over freq.
- Hi directivity in the vertical space
- Hi coverage in the horizontal area.
Specifically the 3rd criterium is key here. If you look at the sound spectrum of musical instruments and human voice (including how our ears work) I came to the conclusion that I had to stay below 200 Hz as a cross over point. Also because the sub will be in trouble going higher and placing it more critical. Looking at the frequency curve of the Faital in a closed box, it rolls of nicely from 180 Hz downwards. So 180 Hz @ 1 liter cabinet volume per driver is the optimum I could get, its the software that tells me this. This also satisfies my rule to have all critical frequencies played from 1 box. Crossing is always a challenge and putting the point around 180 Hz is a safe place to be here, as for my design rules.
You can also look at the graph, Faital supplies for this driver, it also show rolling of around that area.
Now your second question is interesting, of course it is NOT OK to have an excursion of 4 mm (or more) for this driver. As you wonder why, this is how I approach a design (or least part of it). What I do, when designing, is ALSO look at the point where it all starts to go WRONG. The Faital has a Magnetic Gap Depth of 4 mm, so THAT's where you start killing your driver voice coil. Again using bass box Pro, it tells me that I need to drive the Faital with about 100 watt to come CLOSE to 4mm excursion. Because of the damping factor of a closed cabinet, the more movement, the more damping, since the air IN the box BEHIND the driver is compressed when the cone moves INWARDS. These driver a very solid, but have a light cone, so air compression plays an important role here.
Since I know that 100 watt is the absolute limit for this driver, I know that my design can handle around 400 watts (with 4 drivers) as an absolute maximum. On the safe side, I use 75% of the max times 2 for my amp choice. Remember that you are way better of having a big amp driving your speakers at half to three-quarters of power than a small amp cranked to the max. In my case I use Crown XLS that do around 750 watts @ 8 ohms. Using my rule (75% of 400 x 2) is 600 watts. I have NEVER blown 1 driver, neither have all my customers.
Last question, I stuff the closed cabinet with Baff wadding, but ANY good quality damping material will do. Its merely to avoid "ringing" of the cabinet, IF this ever happens. Play with it, I could measure some peaks, but it was hard to hear. Damped fully, it gave a nice "smooth" character to the cabinet.
I build these cabinet using 12 mm multiplex, 1 chamber for each driver (so 4 chambers).
kind regards,
Frans
Wae
Sincere thanks for some great information.
I had in mind to build a Bose L1 (on steroids) using 24 Faital Pro 3FE25s per side but your system looks like I might be overdoing it a bit. I have posted in the PA section of the site. I had help there from djk and chris661. Can I ask you:
If I crossover at 180Hz to the bins what design woofer is capable of crossing over that high? (most of the designs in freespeakerplans (like Cubo15) only go up to 110. djks PPSL will cross much higher (250) but from what you say about crossing in the 'vocal' range I don't want to build something that might degrade the vocals and 4 Kappa Pro 15 LF-2s are an expensive option (although the PPSL design is said to give high quality distortion free bass). My whole point is to build a powerful but SMALL footprint system for 2-300 people venue where all is mixed through the system but to use it just for vocals for small venues. Your columns are ideal but I'm not sure now about the bass bins. Any help appreciated.
Sincere thanks for some great information.
I had in mind to build a Bose L1 (on steroids) using 24 Faital Pro 3FE25s per side but your system looks like I might be overdoing it a bit. I have posted in the PA section of the site. I had help there from djk and chris661. Can I ask you:
If I crossover at 180Hz to the bins what design woofer is capable of crossing over that high? (most of the designs in freespeakerplans (like Cubo15) only go up to 110. djks PPSL will cross much higher (250) but from what you say about crossing in the 'vocal' range I don't want to build something that might degrade the vocals and 4 Kappa Pro 15 LF-2s are an expensive option (although the PPSL design is said to give high quality distortion free bass). My whole point is to build a powerful but SMALL footprint system for 2-300 people venue where all is mixed through the system but to use it just for vocals for small venues. Your columns are ideal but I'm not sure now about the bass bins. Any help appreciated.
To cross at 200Hz upwards, you'll need a direct-radiating enclosure. That is, one where the cone (usually facing outwards) provides most of the output, with the cabinet helping at the bottom end (ported box, transmission line, or even sealed). That way, you'll get pretty much clean response to the top of the woofer's passband. Even with heavy-duty 15"s, that's gonna be past 1kHz.
FWIW, I wouldn't bother with the Eminence drivers. Here's a driver that'll do the work of 2x Kappa-15 LF-2: B&C Speakers
I don't know how much that one costs, but its worth looking into. Others are available.
Chris
FWIW, I wouldn't bother with the Eminence drivers. Here's a driver that'll do the work of 2x Kappa-15 LF-2: B&C Speakers
I don't know how much that one costs, but its worth looking into. Others are available.
Chris
I always go for ported (bass reflex) enclosures combined with these top cabinets, as Chris also stated. Direct radiating is the best option here, however, as always there is a penalty. 😕
Ported boxes go less loud as opposed to (tapped) horns and the likes. You miss at least 3 - 6 dB, depending on the quality of the horn design. That means 2 - 4 times the power required (each additional 3 dB you want to get is double the amp power required), but the nice thing here is, with the entrance of digital (class D) amps prices have gone down per watt. You would need at least 2 - 3 kW to drive them nicely.
You would need at least 2 x 15-inch or 4 x 12-inch (which is about the same cone surface) to keep up with the tops and "fill" the room (200 - 300 people may not seem much, but a small room packed with people has a high damping), requires some power to fill. Correct DSP settings prevent blowing drivers, just as enough amp power does.
Their are enough options here, B&C, 18-sound, Faital Pro, amongst others. Go for Neodymium magnets, saves weight and adds efficiency.
It also requires clever placing of the subs (all in one in corner or diagonal in 2 opposite corners) to get some acoustic help of the room, and you need all the help there is. Nice thing, IT's for FREE 😀.
Do NOT place subs at both sides of a stage, you miss additional dB's as a result of acoustic coupling of the subs when stacked. Most of the gigs, I place the subs in 1 corner, trying to place the top on about the same line to avoid serious timing issues. An other trick is, placing all subs UNDER the stage, when the stage is placed against a back wall it forms a big cavity, you place the subs UNDER the (middle of the) stage against the wall, all in one line against each other as one set. The bass travels far in the room this way and the musicians are "standing" on the bass frequences which for them appears as a nice fat sound. NO feed back from kick mikes and the likes into the subs, the stage is in between.😎
Placing the subs diagonal in the room in opposite corners may seem a bit strange, but what happens is, you kind of "fool" your brain / ears. Unless your are exactly in the middle of the room, there always is a timing difference between sound from one sub in corner A versus the sound coming from the other sub in corner B. This way, you smear out the low note over a slightly longer time in your brain, because when the note from sub A is dying out, the same note from sub B kicks in. It is perceived as "more" bass, which their isn't, that's why I said "fool" the brain here. Works surprisingly well, or I fool myself here...😛 but only in small room, like you target at. In larger hall, you would get an echo and need delay lines to decrease the timing difference, also people in the back of the room would get an over kill on low frequences.
Hope this gets you on your way to a clever PA.
Never liked BOSE any way (my taste and opinion but still...). They build a PA that holds the same theorie as their home audio stuff for extensive spreading of sound. Drivers are to small, beam all over the place which completely ruines the directivity and you get a DIP in the mid-bass / vocal sound area. YOU DON WANT THAT in a PA, it only needs to sound where people are, and I've NEVER seen audience crawling against the ceiling (again that might be just me...😛). Not to mention phasing issues and, because of lack of directivity, they don't play loud over a larger distance, so more power, more distortion, it's just the WRONG way. I've listened to them and they are kind of alright to play (classical / easy listening / small Jazz combo) as a back ground sound system, sort of Hifi but nor really.
I'll have a look at the PA section.
kind regards,
Frans
Ported boxes go less loud as opposed to (tapped) horns and the likes. You miss at least 3 - 6 dB, depending on the quality of the horn design. That means 2 - 4 times the power required (each additional 3 dB you want to get is double the amp power required), but the nice thing here is, with the entrance of digital (class D) amps prices have gone down per watt. You would need at least 2 - 3 kW to drive them nicely.
You would need at least 2 x 15-inch or 4 x 12-inch (which is about the same cone surface) to keep up with the tops and "fill" the room (200 - 300 people may not seem much, but a small room packed with people has a high damping), requires some power to fill. Correct DSP settings prevent blowing drivers, just as enough amp power does.
Their are enough options here, B&C, 18-sound, Faital Pro, amongst others. Go for Neodymium magnets, saves weight and adds efficiency.
It also requires clever placing of the subs (all in one in corner or diagonal in 2 opposite corners) to get some acoustic help of the room, and you need all the help there is. Nice thing, IT's for FREE 😀.
Do NOT place subs at both sides of a stage, you miss additional dB's as a result of acoustic coupling of the subs when stacked. Most of the gigs, I place the subs in 1 corner, trying to place the top on about the same line to avoid serious timing issues. An other trick is, placing all subs UNDER the stage, when the stage is placed against a back wall it forms a big cavity, you place the subs UNDER the (middle of the) stage against the wall, all in one line against each other as one set. The bass travels far in the room this way and the musicians are "standing" on the bass frequences which for them appears as a nice fat sound. NO feed back from kick mikes and the likes into the subs, the stage is in between.😎
Placing the subs diagonal in the room in opposite corners may seem a bit strange, but what happens is, you kind of "fool" your brain / ears. Unless your are exactly in the middle of the room, there always is a timing difference between sound from one sub in corner A versus the sound coming from the other sub in corner B. This way, you smear out the low note over a slightly longer time in your brain, because when the note from sub A is dying out, the same note from sub B kicks in. It is perceived as "more" bass, which their isn't, that's why I said "fool" the brain here. Works surprisingly well, or I fool myself here...😛 but only in small room, like you target at. In larger hall, you would get an echo and need delay lines to decrease the timing difference, also people in the back of the room would get an over kill on low frequences.
Hope this gets you on your way to a clever PA.
Never liked BOSE any way (my taste and opinion but still...). They build a PA that holds the same theorie as their home audio stuff for extensive spreading of sound. Drivers are to small, beam all over the place which completely ruines the directivity and you get a DIP in the mid-bass / vocal sound area. YOU DON WANT THAT in a PA, it only needs to sound where people are, and I've NEVER seen audience crawling against the ceiling (again that might be just me...😛). Not to mention phasing issues and, because of lack of directivity, they don't play loud over a larger distance, so more power, more distortion, it's just the WRONG way. I've listened to them and they are kind of alright to play (classical / easy listening / small Jazz combo) as a back ground sound system, sort of Hifi but nor really.
I'll have a look at the PA section.
kind regards,
Frans
Thanks Chris,
trying to absorb all the info and figure out T/S, Hornresp etc..Bassbox looks good too. The B&C is not as expensive as 2 of the Kappas so worth changing tack on the PPSL maybe. Appreciate that at some point I'm going to have press go and get into it...diyaudio is a great site. Ill keep diggin for a short while yet
Frans,
Thanks again for your tips which I will take on board especially about stacking the bass bins.
As a basic starting point to cater for my requirements 200-300 venue
Do you think I may now need :
TOPS: two sets of 4 x 4" columns per side 1200-1500W for 4 columns
BOTTOMS: 2 x vented cabs (1 x 15" in each) and 2-3kW for 2 cabs (1-1.5kW/cab)
something like a DCX2496 to control it ?
Can you recommend a Bass cab design for the 15TBW100 Chris mentioned? or a good match for your tops?
Thanks,
Ed
Thanks again for your tips which I will take on board especially about stacking the bass bins.
As a basic starting point to cater for my requirements 200-300 venue
Do you think I may now need :
TOPS: two sets of 4 x 4" columns per side 1200-1500W for 4 columns
BOTTOMS: 2 x vented cabs (1 x 15" in each) and 2-3kW for 2 cabs (1-1.5kW/cab)
something like a DCX2496 to control it ?
Can you recommend a Bass cab design for the 15TBW100 Chris mentioned? or a good match for your tops?
Thanks,
Ed
Hi Ed,
Yes, that would be about right, but you may need to "tame" the tops, because 4 of them will out perform 2 bass reflex subs. Should not be a problem, most speakers sound "better" when not pushed to the limit.
Recommending a design?
For the tops, you already have all the data, it's up to you how you want the Looks to be. Design and build a column that holds 2 or 4 separate compartments (2x 1,8 liters OR 4 x 0,9 liters), so that's 2 speakers in one compartment or each speaker in it's own compartment. The compartments are intended to protect the driver in case one fails. ALSO, it makes the cabinet stronger and you MUST build cabinets road proof, although not wanted, they WILL fall out of a car, of the stage and so on and so on.
Connect the 4" 2 x 2 in series and connect those 2 sets parallel. If you use 8 ohm speakers, you will end up at 8 ohm for each column top with 4 speakers. The grill could be folded around the front and screwed at the sides, just experiment with one test version until you have got what you like. I already posted a picture, have a close look at it, so you understand what I did.
I did a lot of surfing on the internet looking at all manufacturers and combined that to my own design.
There are basics you MUST have, like;
- It must be mounted on a pole (35 mm most likely). But IF you want to stack 2 on one pole on top of each others there's a challenge.
- The pole will be at the back of the tops, NOT under the tops (that would prevent you from stacking more on one pole. Where are the speakon's going to go? There isn't much room.
- Since you have a 2 way system, how can you make speaker connections (low-amp to subs and high-amp to tops) in such a way you don't mix them up if under stress for a gig with little setup time. I once made that mistake which has a very strange end result. You connect the low-amp to the tops, but the low-amp stops at 180 Hz (DSP setting) and the tops start functioning at 180 Hz. The net result is a very narrow band where you hear "some" sound, but not much. Then of course, you connect the high-amp to the subs, but the subs are not designed to shine above 180 Hz. Net result, put all on max and hear almost nothing 😕 very 😕
My solution is to make ALL speaker cables are 4 way. The subs are on 1+ and 1-, the tops are on 2+ & 2-. FOOL proof and faster to set up at the same prices or slightly less.
I think that's for you to decide.
For the bass, I could draw up a version for you, but why not download a version on say WIN-ISD or buy BassBox Pro and learn how to. It's not that hard.
As a start, I attached a quick version for the 15TBW100. Focus on the lower part (below 180 Hz) since that is the area for the sub to work in. This cabinet with your preferred driver hits 116 dB at 30 Hz with 1000 watt, 2 cabinets will almost hit 120 dB. If you stack them in a corner, due to acoustic coupling it may go at around 123 - 125 dB. That should be loud enough for an audience of 200 people or so. So MOST pubs and small venues are supported.
The picture shows all data (INTERNAL DIMENSIONS!!). I have defined 2 bass reflex pipes of 100mm internal size, the tuning is 32 Hz (use PVC pipe at the handy store). They are 65 cm long, so you need to add a 90 degree bend to make it fit in the box. Measure the length in the MIDDLE of the pipe. The DSP is set at 35 Hz with a Q (quality setting) of 1,4 and 24 dB / octave roll-off. Could be a bit lower, but not much. This setting will provide nice protection.
REMEMBER, this is just a first start, you need to add damping the make a sound of the sub to your likings, experiment with the DSP. BE careful here, the DSP is to be used to PROTECT your driver, the higher you set you Q setting, the louder it will sound at the roll-off freq. BUT excursion will go through the roof, resulting in your driver "bottoming out". The voice coil will hit the metal magnet structure and slam to pieces. THAT is the challenge of DIY. Begin with max 500 watts and watch you drivers carefully, uncontrolled excursion is WRONG DSP setting. Most likely you set it TO MUCH under the 32 Hz tuning frequency of the bass reflex, and your speaker starts to work in "open air" so to say. The cabinet does not provide a correct supporting environment any more. The reason for this is, as one of the draw backs of a bass reflex, under the tuning frequency (32 Hz in our case) the bass reflex pipe becomes a "hole in your box" that is NOT supporting your speaker any longer. And putting 1000 watt's or more to a speaker in open air is a good You-Tube film "how to kill the speaker". 😀
Although you may want lower and more, there is always an end to the capability of stuff you buy, no matter what cost. THE MOST made mistake is to crank up all until there is no "air" in your PA, so (maybe loud) it starts to sound crap. It's way better to have a less loud nice sounding PA. I've never heard people complain about my PA not being loud enough. I've seen audience leave at gigs that sound crap.
I would advise (for THIS design) never to go under the 30 Hz as the high pass point of the DSP, so roll off will be at about the tuning fervency of the box ( a bit lower to get most out of it). In the beginning, play it safe and start learning, focus at does it sound right, NOT is a as loud as hell.
Must documentation is clear enough here, take time to read an understand.
When you have questions, that's what this forum is all about, just post them.
If this all does not work out, send me a PM and will see how get you on the road.
OK?
Ooh, after burner, ALL speakers need to "burn in" as people call it, the speaker material needs to settle in and get the correct flexibility. Give your speakers a few hours of music at a few hundred watts to start burning in. The sound will change a bit, as will the behaviour of the drivers. The free air resonance will drop a few Hz in most cases. So tuning a brand new driver is not the best option, burn them in first.
kind regards,
Yes, that would be about right, but you may need to "tame" the tops, because 4 of them will out perform 2 bass reflex subs. Should not be a problem, most speakers sound "better" when not pushed to the limit.
Recommending a design?
For the tops, you already have all the data, it's up to you how you want the Looks to be. Design and build a column that holds 2 or 4 separate compartments (2x 1,8 liters OR 4 x 0,9 liters), so that's 2 speakers in one compartment or each speaker in it's own compartment. The compartments are intended to protect the driver in case one fails. ALSO, it makes the cabinet stronger and you MUST build cabinets road proof, although not wanted, they WILL fall out of a car, of the stage and so on and so on.
Connect the 4" 2 x 2 in series and connect those 2 sets parallel. If you use 8 ohm speakers, you will end up at 8 ohm for each column top with 4 speakers. The grill could be folded around the front and screwed at the sides, just experiment with one test version until you have got what you like. I already posted a picture, have a close look at it, so you understand what I did.
I did a lot of surfing on the internet looking at all manufacturers and combined that to my own design.
There are basics you MUST have, like;
- It must be mounted on a pole (35 mm most likely). But IF you want to stack 2 on one pole on top of each others there's a challenge.
- The pole will be at the back of the tops, NOT under the tops (that would prevent you from stacking more on one pole. Where are the speakon's going to go? There isn't much room.
- Since you have a 2 way system, how can you make speaker connections (low-amp to subs and high-amp to tops) in such a way you don't mix them up if under stress for a gig with little setup time. I once made that mistake which has a very strange end result. You connect the low-amp to the tops, but the low-amp stops at 180 Hz (DSP setting) and the tops start functioning at 180 Hz. The net result is a very narrow band where you hear "some" sound, but not much. Then of course, you connect the high-amp to the subs, but the subs are not designed to shine above 180 Hz. Net result, put all on max and hear almost nothing 😕 very 😕
My solution is to make ALL speaker cables are 4 way. The subs are on 1+ and 1-, the tops are on 2+ & 2-. FOOL proof and faster to set up at the same prices or slightly less.
I think that's for you to decide.
For the bass, I could draw up a version for you, but why not download a version on say WIN-ISD or buy BassBox Pro and learn how to. It's not that hard.
As a start, I attached a quick version for the 15TBW100. Focus on the lower part (below 180 Hz) since that is the area for the sub to work in. This cabinet with your preferred driver hits 116 dB at 30 Hz with 1000 watt, 2 cabinets will almost hit 120 dB. If you stack them in a corner, due to acoustic coupling it may go at around 123 - 125 dB. That should be loud enough for an audience of 200 people or so. So MOST pubs and small venues are supported.
The picture shows all data (INTERNAL DIMENSIONS!!). I have defined 2 bass reflex pipes of 100mm internal size, the tuning is 32 Hz (use PVC pipe at the handy store). They are 65 cm long, so you need to add a 90 degree bend to make it fit in the box. Measure the length in the MIDDLE of the pipe. The DSP is set at 35 Hz with a Q (quality setting) of 1,4 and 24 dB / octave roll-off. Could be a bit lower, but not much. This setting will provide nice protection.
REMEMBER, this is just a first start, you need to add damping the make a sound of the sub to your likings, experiment with the DSP. BE careful here, the DSP is to be used to PROTECT your driver, the higher you set you Q setting, the louder it will sound at the roll-off freq. BUT excursion will go through the roof, resulting in your driver "bottoming out". The voice coil will hit the metal magnet structure and slam to pieces. THAT is the challenge of DIY. Begin with max 500 watts and watch you drivers carefully, uncontrolled excursion is WRONG DSP setting. Most likely you set it TO MUCH under the 32 Hz tuning frequency of the bass reflex, and your speaker starts to work in "open air" so to say. The cabinet does not provide a correct supporting environment any more. The reason for this is, as one of the draw backs of a bass reflex, under the tuning frequency (32 Hz in our case) the bass reflex pipe becomes a "hole in your box" that is NOT supporting your speaker any longer. And putting 1000 watt's or more to a speaker in open air is a good You-Tube film "how to kill the speaker". 😀
Although you may want lower and more, there is always an end to the capability of stuff you buy, no matter what cost. THE MOST made mistake is to crank up all until there is no "air" in your PA, so (maybe loud) it starts to sound crap. It's way better to have a less loud nice sounding PA. I've never heard people complain about my PA not being loud enough. I've seen audience leave at gigs that sound crap.
I would advise (for THIS design) never to go under the 30 Hz as the high pass point of the DSP, so roll off will be at about the tuning fervency of the box ( a bit lower to get most out of it). In the beginning, play it safe and start learning, focus at does it sound right, NOT is a as loud as hell.
Must documentation is clear enough here, take time to read an understand.
When you have questions, that's what this forum is all about, just post them.
If this all does not work out, send me a PM and will see how get you on the road.
OK?
Ooh, after burner, ALL speakers need to "burn in" as people call it, the speaker material needs to settle in and get the correct flexibility. Give your speakers a few hours of music at a few hundred watts to start burning in. The sound will change a bit, as will the behaviour of the drivers. The free air resonance will drop a few Hz in most cases. So tuning a brand new driver is not the best option, burn them in first.
kind regards,
Attachments
Hi Frans
You are very generous. Many thanks.
I had already downloaded Winisd and had a go at modelling the B&C driver before you posted. Went with 150 L for no real reason just playing around. I'm not able to upload images here and not sure why but I run linux and I've emailed admin. Here is a google drive link to the screenshots if you want. Made the vent the width of the cabinet again just playing around to see what affects what Port size and tuning freq are linked anyway.
Transfer Function Magnitude:
https://drive.google.com/open?id=0B5lu-Wnk0K53RENrcXRMOGN3bVU
SPL: Port length unusable
https://drive.google.com/open?id=0B5lu-Wnk0K53amZaNnhGU2dpdzA
Air Velocity:
Low I'd say but the port is huge.
https://drive.google.com/open?id=0B5lu-Wnk0K53TEhjYl9aSmRSYjg
Cone excursion: No highpass applied.
https://drive.google.com/open?id=0B5lu-Wnk0K53eE5oMkxHQ3V1R1U
I remodelled it with your BB data and got a very similar set of plots to yours hopefully I'm on the right track.
I have a couple of questions:
I assume the 60L Vb figure in BB s the box volume in Winisd. and the total 75L includes the vent volume. Is that correct?
The first cone resonance figure. I saw somewhere that this should be outside the bandpass range to have no effect on the cabinet. When I remodelled the cab I got this to be 264 Hz but I'll be crossing at 180 or so. Is that ok or does it need to be higher?
Just use the PVC pipe clamps to support the vent?
Cabling: did you connect the amp outputs to a speakon patch panel wired for the 4 way. ? Good solution thanks. I believe HFs can be destroyed by LF signals or is that a myth?
DSP:
In Winisd you can add parametric EQ to the transfer function to basically make it flatter. Is this done with say a DCX2496 when setting up the system and to also apply the high pass filter and crossover point?
Again sincere thanks for a very informative and helpful post and for spending your time on this.
Ed
You are very generous. Many thanks.
I had already downloaded Winisd and had a go at modelling the B&C driver before you posted. Went with 150 L for no real reason just playing around. I'm not able to upload images here and not sure why but I run linux and I've emailed admin. Here is a google drive link to the screenshots if you want. Made the vent the width of the cabinet again just playing around to see what affects what Port size and tuning freq are linked anyway.
Transfer Function Magnitude:
https://drive.google.com/open?id=0B5lu-Wnk0K53RENrcXRMOGN3bVU
SPL: Port length unusable
https://drive.google.com/open?id=0B5lu-Wnk0K53amZaNnhGU2dpdzA
Air Velocity:
Low I'd say but the port is huge.
https://drive.google.com/open?id=0B5lu-Wnk0K53TEhjYl9aSmRSYjg
Cone excursion: No highpass applied.
https://drive.google.com/open?id=0B5lu-Wnk0K53eE5oMkxHQ3V1R1U
I remodelled it with your BB data and got a very similar set of plots to yours hopefully I'm on the right track.
I have a couple of questions:
I assume the 60L Vb figure in BB s the box volume in Winisd. and the total 75L includes the vent volume. Is that correct?
The first cone resonance figure. I saw somewhere that this should be outside the bandpass range to have no effect on the cabinet. When I remodelled the cab I got this to be 264 Hz but I'll be crossing at 180 or so. Is that ok or does it need to be higher?
Just use the PVC pipe clamps to support the vent?
Cabling: did you connect the amp outputs to a speakon patch panel wired for the 4 way. ? Good solution thanks. I believe HFs can be destroyed by LF signals or is that a myth?
DSP:
In Winisd you can add parametric EQ to the transfer function to basically make it flatter. Is this done with say a DCX2496 when setting up the system and to also apply the high pass filter and crossover point?
Again sincere thanks for a very informative and helpful post and for spending your time on this.
Ed
Hi Ed,
Aahah, starting with Win ISD, GREAT. The 150 liters was a bit on the big side, more like 2 x 15 or 18 inch, but anyway. You got started. BB has a "suggest" button that calculates a first version, I always do that, but end up changing stuff to my liking, it is a easy and safe approach though.
I suggested a lower "Q" to make the low end "roll off" a bit, not getting such a steep fall of the low end below the High pass point. Sounds more natural in most cases to have the low-end and high-end roll-off smoother.
About your questions;
75 liters is the total volume including the volume of the 2 bass reflex pipes AND the driver. The software calculates the NET & Total.
Your OK with this cabinet and resonances. What I didn't mention yet is PANEL resonance, be shure to brace AND use 18 mm 13 ply birch plywood. The box is small enough to keep you out of trouble, don't make it smaller, you loose deep bass. I've seen numerous times people that want to use 15 or even 12 mm 5 or 6 ply plywood, because it's costing less AND weighs less. To my (practical experience supported) opinion, a BIG mistake. OK, you win 1 kg or so and a few euro's, but you end up with a sub that can walk of the stage ALL BY ITSELF, neat.... (NOT !). ALSO, because of panel vibrations, the speaker want perform as expected and it sounds crap.
PVC clamps, hum, never thought of that, but I guess the answer is NO. I think you run into construction issues mounting the PVC clamp to the box inside, apart from possible vibrations causing your pipe to start vibrating. DOn't want that. I would make 2 small supporting panels out of plywood (say 15 x 15 cm) with a hole in the middle and size of the external diameter of the pipe and use glue that extends while drying to fix the pipe and the braces to the box. Put one at the bend and one and the beginning of the pipe. The end IS already in the front panel of the box. An other option is to combine these with a brace (most likely at the beginning of the pipe, which will start somewhere halfway the hight of the box), so a brace with 2 holes, but that all depends on where you need to brace and if the combines well. Make a sketch of the sub and try figure it out.
Cabling: good question, NO, use what you may have already, almost any amplifier currently available is a "stereo" amp (an amp with 2 power units, Speakons labeled CH1 & CH2). It has 2 Speakon outputs. Output 1 (CH1) almost ALWAYS is wired for both power units, so 1+ / 1- & 2+ / 2-. You see, its already being taken care of. If NOT in your amp, do it yourself. It's very easy, open up the amp and connect 1+ / 1- of power unit speakon CH2 to the 2+ / 2- of power unit speakon CH1 (ONLY IF THIS SPEAKON CHASSIS CH1 IS NOT WIRED ON 2+ / 2-). You just made your amp as standard using CH1 to connect both sub & Top with a 4 wire cable.
I have added a picture where you can see CH1 wired on all 4 connections of the speakon, this is a Crown XLS. CH2 is blocked with a peace of Gaffa tape, to prevent mistakes in the dark. 😀
DSP, Yes that's a candidate. I have never used it, currently run a DBX PA2, cheap(ish) but with good results for me. DBX has some better more expensive units, but this one did it for me.
The DCX2496 from Behringer has got some positive criticism here on DIY. Looking in the documentation (quick peek), it can do the job. Looks like your setting called " Stereo operation plus 2 subwoofers". They show an active woofer, but that's the same as a separate amp and sub.
I would however advise you to look at some alternatives, some competition have the possibility to connect to a WIFI router (already in the plans for a digital mixer?) and have a tablet (iPad or such) with nice apps access the DSP, they do superb graphics for setting up EQ, filters, etc. AND save settings. Settings saving is a handy feature in case for some reason you need to change the DSP or you changed "something" and want you original setting back in a few seconds.
Also, some DSP's have a "synth" function to add low notes and give that extra bottom IF applied carefully. MOST engineers over-do this in large PA's getting some (in my ears stupid and NOT music related) low rumble under the sound of the band. If you look at the stage you see a band with drums and bass guitar and HERE an earth quake dropping on top of the scene.... 😱 I think, what's wrong with you, this is not "Jurassic Park 3 extended version", it's a band playing.
The lowest note you get is around 27 - 30 Hz like the low B of a 5-string bass OR the lowest note of a full keyboard / piano. The rumbles are below 20 Hz.
Anyway, next steps please.
Keep up the spirit, you'l get there.
kind regards, Frans
Aahah, starting with Win ISD, GREAT. The 150 liters was a bit on the big side, more like 2 x 15 or 18 inch, but anyway. You got started. BB has a "suggest" button that calculates a first version, I always do that, but end up changing stuff to my liking, it is a easy and safe approach though.
I suggested a lower "Q" to make the low end "roll off" a bit, not getting such a steep fall of the low end below the High pass point. Sounds more natural in most cases to have the low-end and high-end roll-off smoother.
About your questions;
75 liters is the total volume including the volume of the 2 bass reflex pipes AND the driver. The software calculates the NET & Total.
Your OK with this cabinet and resonances. What I didn't mention yet is PANEL resonance, be shure to brace AND use 18 mm 13 ply birch plywood. The box is small enough to keep you out of trouble, don't make it smaller, you loose deep bass. I've seen numerous times people that want to use 15 or even 12 mm 5 or 6 ply plywood, because it's costing less AND weighs less. To my (practical experience supported) opinion, a BIG mistake. OK, you win 1 kg or so and a few euro's, but you end up with a sub that can walk of the stage ALL BY ITSELF, neat.... (NOT !). ALSO, because of panel vibrations, the speaker want perform as expected and it sounds crap.
PVC clamps, hum, never thought of that, but I guess the answer is NO. I think you run into construction issues mounting the PVC clamp to the box inside, apart from possible vibrations causing your pipe to start vibrating. DOn't want that. I would make 2 small supporting panels out of plywood (say 15 x 15 cm) with a hole in the middle and size of the external diameter of the pipe and use glue that extends while drying to fix the pipe and the braces to the box. Put one at the bend and one and the beginning of the pipe. The end IS already in the front panel of the box. An other option is to combine these with a brace (most likely at the beginning of the pipe, which will start somewhere halfway the hight of the box), so a brace with 2 holes, but that all depends on where you need to brace and if the combines well. Make a sketch of the sub and try figure it out.
Cabling: good question, NO, use what you may have already, almost any amplifier currently available is a "stereo" amp (an amp with 2 power units, Speakons labeled CH1 & CH2). It has 2 Speakon outputs. Output 1 (CH1) almost ALWAYS is wired for both power units, so 1+ / 1- & 2+ / 2-. You see, its already being taken care of. If NOT in your amp, do it yourself. It's very easy, open up the amp and connect 1+ / 1- of power unit speakon CH2 to the 2+ / 2- of power unit speakon CH1 (ONLY IF THIS SPEAKON CHASSIS CH1 IS NOT WIRED ON 2+ / 2-). You just made your amp as standard using CH1 to connect both sub & Top with a 4 wire cable.
I have added a picture where you can see CH1 wired on all 4 connections of the speakon, this is a Crown XLS. CH2 is blocked with a peace of Gaffa tape, to prevent mistakes in the dark. 😀
DSP, Yes that's a candidate. I have never used it, currently run a DBX PA2, cheap(ish) but with good results for me. DBX has some better more expensive units, but this one did it for me.
The DCX2496 from Behringer has got some positive criticism here on DIY. Looking in the documentation (quick peek), it can do the job. Looks like your setting called " Stereo operation plus 2 subwoofers". They show an active woofer, but that's the same as a separate amp and sub.
I would however advise you to look at some alternatives, some competition have the possibility to connect to a WIFI router (already in the plans for a digital mixer?) and have a tablet (iPad or such) with nice apps access the DSP, they do superb graphics for setting up EQ, filters, etc. AND save settings. Settings saving is a handy feature in case for some reason you need to change the DSP or you changed "something" and want you original setting back in a few seconds.
Also, some DSP's have a "synth" function to add low notes and give that extra bottom IF applied carefully. MOST engineers over-do this in large PA's getting some (in my ears stupid and NOT music related) low rumble under the sound of the band. If you look at the stage you see a band with drums and bass guitar and HERE an earth quake dropping on top of the scene.... 😱 I think, what's wrong with you, this is not "Jurassic Park 3 extended version", it's a band playing.
The lowest note you get is around 27 - 30 Hz like the low B of a 5-string bass OR the lowest note of a full keyboard / piano. The rumbles are below 20 Hz.
Anyway, next steps please.
Keep up the spirit, you'l get there.
kind regards, Frans
Attachments
Hi Frans,
Thanks again for your help. I'm very grateful.
I modeled the system using the Q values that you suggested and will use 18mm ply also. I will (if I can) incorporate the vent supports into a cross brace if possible as I have access to a laser cutter which might make things easier. Thanks for the cabling info also. This will make for an easier and safer connection to the different speakers.
I had actually looked at a digital mixer with wifi (Soundcraft Ui16) which is also rack mounted. I'm not sure if that unit can do all the things you mention but it would be great to remotely 'tune' the room and set up crossovers etc. What unit did you have in mind?
I'm not sure if I have use for an earthquake setting in the PA but you never know 😱
I modeled the system with both WinIsd and Hornresp and would ask you to have a look at the plots I got.
1 Link below is just the SPL output and the Box details. I played around with parametric filters to flatten the lower end of the output but the cone excursion and vent air velocity go through the roof! I used a 1500W signal for all the plots in both softwares. I am not sure I have it all correct though.
https://drive.google.com/open?id=0B5lu-Wnk0K53UUR0OHViQVBHOXc
2 Link below is the cone excursion and the vent and port details
Slightly shorter than your BB port length but I don't seem to be able to get 65cm with 35Hz tuning maybe I'm doing something wrong.
https://drive.google.com/open?id=0B5lu-Wnk0K53dEQ3dEFkX2pYdmM
3 Link below is the Port air velocity and the Filter details. Both filters are Q1.4 and 4th order Butterworth. Should I assume that if I plug these values into a DSP I should get this response curve (or near enough)
https://drive.google.com/open?id=0B5lu-Wnk0K53aWROcFA1S1YzWEE
4. Phase. This one I don't really understand. I can see the amount of phase change over the passband but is this acceptable ? Is it possible to keep this 'in phase' for the range of frequencies ?
5 Hornresp. I also modeled it in Hornresp and the plots dont seem to be hugely dissimilar. I've just overlaid them over the Winisd phase response and again used a 1500W at 3.2 Ohm input for Eg. The phase plot is different for the passband not going below the 0 deg point.
As I say I'm sot sure if I have any of this correct. Hopefully you can shed some light on it for me.
https://drive.google.com/open?id=0B5lu-Wnk0K53NGY4VWJhN1BtTTg
https://drive.google.com/open?id=0B5lu-Wnk0K53S1lWQ2FFbGxYVWc
Thanks again for all your help Frans.
Thanks again for your help. I'm very grateful.
I modeled the system using the Q values that you suggested and will use 18mm ply also. I will (if I can) incorporate the vent supports into a cross brace if possible as I have access to a laser cutter which might make things easier. Thanks for the cabling info also. This will make for an easier and safer connection to the different speakers.
I had actually looked at a digital mixer with wifi (Soundcraft Ui16) which is also rack mounted. I'm not sure if that unit can do all the things you mention but it would be great to remotely 'tune' the room and set up crossovers etc. What unit did you have in mind?
I'm not sure if I have use for an earthquake setting in the PA but you never know 😱
I modeled the system with both WinIsd and Hornresp and would ask you to have a look at the plots I got.
1 Link below is just the SPL output and the Box details. I played around with parametric filters to flatten the lower end of the output but the cone excursion and vent air velocity go through the roof! I used a 1500W signal for all the plots in both softwares. I am not sure I have it all correct though.
https://drive.google.com/open?id=0B5lu-Wnk0K53UUR0OHViQVBHOXc
2 Link below is the cone excursion and the vent and port details
Slightly shorter than your BB port length but I don't seem to be able to get 65cm with 35Hz tuning maybe I'm doing something wrong.
https://drive.google.com/open?id=0B5lu-Wnk0K53dEQ3dEFkX2pYdmM
3 Link below is the Port air velocity and the Filter details. Both filters are Q1.4 and 4th order Butterworth. Should I assume that if I plug these values into a DSP I should get this response curve (or near enough)
https://drive.google.com/open?id=0B5lu-Wnk0K53aWROcFA1S1YzWEE
4. Phase. This one I don't really understand. I can see the amount of phase change over the passband but is this acceptable ? Is it possible to keep this 'in phase' for the range of frequencies ?
5 Hornresp. I also modeled it in Hornresp and the plots dont seem to be hugely dissimilar. I've just overlaid them over the Winisd phase response and again used a 1500W at 3.2 Ohm input for Eg. The phase plot is different for the passband not going below the 0 deg point.
As I say I'm sot sure if I have any of this correct. Hopefully you can shed some light on it for me.
https://drive.google.com/open?id=0B5lu-Wnk0K53NGY4VWJhN1BtTTg
https://drive.google.com/open?id=0B5lu-Wnk0K53S1lWQ2FFbGxYVWc
Thanks again for all your help Frans.
Frans,
I am with you.
I reused the eight Bose drivers from a set of 802's and placed eight per side in the miniature line array ( the correct orientation, ha,ha) just like you have and added a sub for each with a simple socket and pole for each so the sub supports the array. two subs and two arrays.
Made crossovers to simplify ( no active required) for my friends who wanted better quality for mic'ed acoustic instruments and voice along with a solid Bass.
We have run DI'ed electric Bass and Mic'ed upright bass with lot's of compliments on the system.
I also like the fact that phase cancellation between the multiple drivers in the array work to our advantage to make feedback almost impossible with a mic in close proximity to the arrays.
And yes, the "focus allows us to control the audience sound field and when used in a room it takes away the bounce off the ceiling and floor, leaving it much clearer for the audience.
Cheers,
Tom eh
I am with you.
I reused the eight Bose drivers from a set of 802's and placed eight per side in the miniature line array ( the correct orientation, ha,ha) just like you have and added a sub for each with a simple socket and pole for each so the sub supports the array. two subs and two arrays.
Made crossovers to simplify ( no active required) for my friends who wanted better quality for mic'ed acoustic instruments and voice along with a solid Bass.
We have run DI'ed electric Bass and Mic'ed upright bass with lot's of compliments on the system.
I also like the fact that phase cancellation between the multiple drivers in the array work to our advantage to make feedback almost impossible with a mic in close proximity to the arrays.
And yes, the "focus allows us to control the audience sound field and when used in a room it takes away the bounce off the ceiling and floor, leaving it much clearer for the audience.
Cheers,
Tom eh
Hi Ed,
Sorry for the late response, I had some problems with my health, just got back on diyAudio and read your message.
Turned out, some smart *** had turned all amp's to max volume (they were around 75% when we finished the sound check).
BOARDS? Key is nice sounding flexible EQ AND headroom (at least, that's where it all fails or glories to my ears).
I've used analog boards for decades, STILL love them for the sound, but they're big, heavy and you need some external 19" devices. There are some nice analog board that have effects in them (like soundcraft EFX series), if you add a 4 compressor limiter in 1 box (various brands form cheap behringer to DBX), you'll have a easy to use kit.
Digital boards (I've used Presonus as a first digital board because they still "feel" like analog) might give you a steep learning curve, BUT are more a "all in one" package. There are various kids on the block, like Sony, Personus, Behringer, Soundcraft. All have some pro's and con's. Surf the web for some (youtube) info and reviews.
For my business, I use a Soundcraft SI expression 2 currently, love the sound, almost like my older analog boards. Behringer X32 gets good press also, some more functionality in user interface, but I still have this voice in my head from the early days when they where cheap but you could see, feel and hear that. Oh well, maybe it's just me, it's been used a LOT and MIDAS is a big name behind it.
1500 Watts is a bit on the optimistic side I guess 😉. The max power stated for a driver is NOT excursion related, but mostly current related (how much current will it handle without problems through the voice coil during some hours of testing). Look at the specs of the driver what they used. ANYWAY, your plots tell you to turn down the volume, it's NOT persee the cabinet that's wrong. In fact, it ISN't, it shows you that your driver is overloaded. If you would tweak the cabinet to keep excursion within max, you will most likely end up at a tuning frequency above 100 Hz (just a guess.., at least WAY to high). Using a 1500 watt amp, is not intended to run it at its max (NEVER run amps at max power), it is used to have sufficient "head-room" to be able to handle the dynamics of the sound of the band.
The fact that vent air goes through the ceiling is just the consequence of the above, again TO MUCH power. The be complete, you COULD tame the vent air speed by increasing the diameter of the vent (which impacts length of the vent). I would not go their now, just figure your max power (decrease power to where xmax is just reached.) You're save then, most likely vent air speed will be acceptable at this point.
OK, about vents: Your bass reflex cabinet with the driver is supposed to act as one unit, but in fact it is 3 units combined. First the driver, that's a given, next the cabinet which you NEED to help the driver by giving it a "good working space to perform at its max..", THIRD and most important, we have chosen a bass reflex cabinet, SO we need a VENT. Now this vent is a strange animal, often referred to as a "Helmholtz resonator". What happens in this resonator that, based on its VOLUME, the air start to resonate at a given frequency, based on this volume. Now when you couple this resonator to the speaker, by placing a pipe (vent) in the box as the ONLY exit to the outside world, the driver will move air on which the vent will react by resonating the air INSIDE the vent. At the bass reflex tuning frequency, this vent resonation is at its max, giving the best support for the driver. You can see this when looking at the frequency chart, xmax is at its LOWEST. Now that's all fine but this would mean you have a one note wonder (which it actually is) BUT above AND below this frequency you will also play notes, where the support of the vent will be less until you get at the "harmonics". We will stop here, since things will get complicated.
ANY WAY, it is NOT the length that should be exactly 65 cm, it's the volume you need, which calculates by the diameter giving the length. You should see this, when changing either cabinet volume, tuning freq., type of driver, etc. It is a SYSTEM with 3 components and they need to be aligned. That is why you CANNOT just change the driver in a given cabinet, you might even blow it in case of big mismatch.
SO, length is not an issue in the way you look at it, just use what ever your software tells you.
YES, you got it. In fact, you now how to play with it now, higher Q is steeper roll off, is tougher for the driver, "may" sound less musical and so forth....
Hmm, based upon my brief attempt to explain the system of a bass reflex cabinet, this is one of the fenomina. YES you will always have phase shifts, the fact that the cabinet shows phase shifts should not be the problem. It "could" at the point where you set the cross over, in our case around 180 Hz. This could be handled by "complex" settings of the cross-over. I would not worry to much at this point in time, let's get the cabinets first on the stage. Phase changes are a fact of life in a bass reflex (in fact ANY) cabinet).
Hope i did answer your questions.
I think you have chosen a solid driver, design looks good, time for saw dust...😀
kind regards,
Frans
Sorry for the late response, I had some problems with my health, just got back on diyAudio and read your message.
I have no experience with the Ui16, but you need a tablet (iPad) to control it. I DON't like tablet as the main control interface. I once had an important demo gig in a church, set up the PA, did some extensive sound checking to make it work (churches and loud bands, hmmmmm..). Anyway, we were al set for the gig, went to grap some food, came back and when the show began, I took my iPad, walked to the stage. Then, ALL HELL broke loose!!!. As soon as the singer wanted to welcome the crowd, a GIGANTIC feedback (6kW PA🙁 ) was killing all ears of the audience (and me..). An iPad is not a good interface to go figure out what's going on, its just panic and master faders down. From that day on till now, I only use an iPad on stage to help dailing in the monitors.
Turned out, some smart *** had turned all amp's to max volume (they were around 75% when we finished the sound check).
BOARDS? Key is nice sounding flexible EQ AND headroom (at least, that's where it all fails or glories to my ears).
I've used analog boards for decades, STILL love them for the sound, but they're big, heavy and you need some external 19" devices. There are some nice analog board that have effects in them (like soundcraft EFX series), if you add a 4 compressor limiter in 1 box (various brands form cheap behringer to DBX), you'll have a easy to use kit.
Digital boards (I've used Presonus as a first digital board because they still "feel" like analog) might give you a steep learning curve, BUT are more a "all in one" package. There are various kids on the block, like Sony, Personus, Behringer, Soundcraft. All have some pro's and con's. Surf the web for some (youtube) info and reviews.
For my business, I use a Soundcraft SI expression 2 currently, love the sound, almost like my older analog boards. Behringer X32 gets good press also, some more functionality in user interface, but I still have this voice in my head from the early days when they where cheap but you could see, feel and hear that. Oh well, maybe it's just me, it's been used a LOT and MIDAS is a big name behind it.
1500 Watts is a bit on the optimistic side I guess 😉. The max power stated for a driver is NOT excursion related, but mostly current related (how much current will it handle without problems through the voice coil during some hours of testing). Look at the specs of the driver what they used. ANYWAY, your plots tell you to turn down the volume, it's NOT persee the cabinet that's wrong. In fact, it ISN't, it shows you that your driver is overloaded. If you would tweak the cabinet to keep excursion within max, you will most likely end up at a tuning frequency above 100 Hz (just a guess.., at least WAY to high). Using a 1500 watt amp, is not intended to run it at its max (NEVER run amps at max power), it is used to have sufficient "head-room" to be able to handle the dynamics of the sound of the band.
The fact that vent air goes through the ceiling is just the consequence of the above, again TO MUCH power. The be complete, you COULD tame the vent air speed by increasing the diameter of the vent (which impacts length of the vent). I would not go their now, just figure your max power (decrease power to where xmax is just reached.) You're save then, most likely vent air speed will be acceptable at this point.
OK, about vents: Your bass reflex cabinet with the driver is supposed to act as one unit, but in fact it is 3 units combined. First the driver, that's a given, next the cabinet which you NEED to help the driver by giving it a "good working space to perform at its max..", THIRD and most important, we have chosen a bass reflex cabinet, SO we need a VENT. Now this vent is a strange animal, often referred to as a "Helmholtz resonator". What happens in this resonator that, based on its VOLUME, the air start to resonate at a given frequency, based on this volume. Now when you couple this resonator to the speaker, by placing a pipe (vent) in the box as the ONLY exit to the outside world, the driver will move air on which the vent will react by resonating the air INSIDE the vent. At the bass reflex tuning frequency, this vent resonation is at its max, giving the best support for the driver. You can see this when looking at the frequency chart, xmax is at its LOWEST. Now that's all fine but this would mean you have a one note wonder (which it actually is) BUT above AND below this frequency you will also play notes, where the support of the vent will be less until you get at the "harmonics". We will stop here, since things will get complicated.
ANY WAY, it is NOT the length that should be exactly 65 cm, it's the volume you need, which calculates by the diameter giving the length. You should see this, when changing either cabinet volume, tuning freq., type of driver, etc. It is a SYSTEM with 3 components and they need to be aligned. That is why you CANNOT just change the driver in a given cabinet, you might even blow it in case of big mismatch.
SO, length is not an issue in the way you look at it, just use what ever your software tells you.
YES, you got it. In fact, you now how to play with it now, higher Q is steeper roll off, is tougher for the driver, "may" sound less musical and so forth....
Hmm, based upon my brief attempt to explain the system of a bass reflex cabinet, this is one of the fenomina. YES you will always have phase shifts, the fact that the cabinet shows phase shifts should not be the problem. It "could" at the point where you set the cross over, in our case around 180 Hz. This could be handled by "complex" settings of the cross-over. I would not worry to much at this point in time, let's get the cabinets first on the stage. Phase changes are a fact of life in a bass reflex (in fact ANY) cabinet).
Well, if more than one design tools tells you almost the same, I'd say your good. As stated before, this is NOT simple business, BUT with what you've got now, I would leave the science in the other camp and go for it.
Hope i did answer your questions.
I think you have chosen a solid driver, design looks good, time for saw dust...😀
kind regards,
Frans