Hi. First time post. I'll try to keep this succinct: my goal is to build (4) large format, professional quality front loaded 2x18 reflex enclosures for live sound reproduction optimized for the B&C 18TBX100. Budget is not a huge concern; I want to do this right the first time around. The subs will be used for a dance band, so they need to play low and hit hard.
I have heard several professional quality front loaded 2x18s like the Clair BT-218, L-Acoustics SB218, Meyer 700HP, and JBL CRS82l. I understand each listening experience was under different conditions using different amplification and processing, but I think it is safe to say these pro level models will outperform your local Guitar Center variety. If possible, I am hoping my design will at least be in the ballpark of the "pros". Wishful thinking? Probably...
I have some basic plans drawn up and long with measurements using BassBox Pro 6. If I present these plans, would someone be willing to take look and make sure I'm headed on the right track? Another set of eyes never hurts before I break out the credit card and the saw.
I have heard several professional quality front loaded 2x18s like the Clair BT-218, L-Acoustics SB218, Meyer 700HP, and JBL CRS82l. I understand each listening experience was under different conditions using different amplification and processing, but I think it is safe to say these pro level models will outperform your local Guitar Center variety. If possible, I am hoping my design will at least be in the ballpark of the "pros". Wishful thinking? Probably...
I have some basic plans drawn up and long with measurements using BassBox Pro 6. If I present these plans, would someone be willing to take look and make sure I'm headed on the right track? Another set of eyes never hurts before I break out the credit card and the saw.
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I just saw a little article on the new bassmaxx 2x18 cabinets. 42x42x22.5 I believe....they were almost flat to 20hz, almost. and they said no EQ was used down low to achieve that. Impressive for touring sound, are you looking for something of that nature? If so I say start with a cabinet size similar to that. If you don't NEED that kind of extension, cabinet size can be much smaller.
Here is a common dual 18" DIY sub from the UK that are comparable to the designs you mention:
Speakerplans.com
G-SUB CUTSHEET - Speakerplans.com Forums - Page 1
Ported Enclosures - Speakerplans.com Forums - Page 1
They are typical dual 18's that roll off around 40 hz.
Speakerplans.com
G-SUB CUTSHEET - Speakerplans.com Forums - Page 1
Ported Enclosures - Speakerplans.com Forums - Page 1
They are typical dual 18's that roll off around 40 hz.
I can go big since these subs will be used for outdoor concerts, hotel grand ballrooms, etc. My current design is 52" x 24" x 30"D (about 16.5 cubic ft) tuned to 32hz. I can post the graphs when I can home.
An initial question, with a large volume enclosures, in general, it is better to tune it lower? BassBox recommends 30hz, but tuning it up to say 35hz certainly increases the efficiency / SPL at the knee. Amplifier power won't be an issue. I don't think we will be driving this babies uber hard. Thoughts?
An initial question, with a large volume enclosures, in general, it is better to tune it lower? BassBox recommends 30hz, but tuning it up to say 35hz certainly increases the efficiency / SPL at the knee. Amplifier power won't be an issue. I don't think we will be driving this babies uber hard. Thoughts?
not good to drive a BR with signals below box/system tuning
so basicly you would want to either tune below what you need....or use low cut/high pass on your signal/amps...or both
but I have zero experience with this stuff, so...
so basicly you would want to either tune below what you need....or use low cut/high pass on your signal/amps...or both
but I have zero experience with this stuff, so...
In general as you tune lower the excursion peak above tuning will required a driver with more excursion. Bassmaxx are loading high end Faital drivers in that cab I think.
Follow the principal of achieving a flat frequency response on what you want. If you want 32 Hz, make sure the design can give you no lower than 32 Hz @ -3 dB. Having a flat frequency response @ 32 Hz would be best but, I don't believe those drivers are capable of giving you that without equalisation involved.
It is interesting you call 16.5 cubic feet a big box. Thirty years ago that would be the standard size for a pro audio bass bin.
hmmm...
and what happens if there is music signal below the tuning frequency ?
The mandatory high pass filter will take care of that. Unless you want the full 20hz and up, then you need to have speakers which will handle that. And amps equally as powerful. Many amps bridged at 4ohms are rated at 1khz, with higher distortion than at lesser loads (higher impedances). Just gotta be aware of all those things.
The bassmaxx boxes I was referring to are the ZV28
http://www.bassmaxx.com/products/subs/profundo-subs/zv28/
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The answer is two-fold. You should tune it low enough so that you attain the frequency response desired WHILE simultaneously keeping the cone excursion in check with the available amplifier power. Remember, there is an excursion PEAK right above the tuning frequency, since the port is a narrow-Q radiator, it only dampens cone excursion over a very small range. It is this peak that is trouble-some---unless of course you have Xmax to spare, which opens up the possibilities for low-tunings because it is a limiting factor.
B&C 18TBX100
pognoot,
There are questions (for the same driver) that keep coming time after time.
You will be happy to know that the same driver is simulated here (some members already there). How would it be for a double sub?! You will need power for these babies (~ 1300W each@6Ohms, 2600W@3Ohms for both RMS).
B&C S18H - Subwoofer - B&C Component Options - 18” Woofer – 18TBX100 8 ohm
B&C 18 TBX100 - www.usspeaker.com
B&C Speakers
Compare response with the specs of the Dynacord Cobra-Subs >30/32/38Hz@-10dB.
DYNACORD – Cobra-4 Systems
http://www.dynacord.com/downloads/cobra_katalog_en.pdf
http://www.dynacord.com/downloads/cobrapwh_datenblatt.pdf
http://www.dynacord.com/downloads/PWH28-EDS.pdf
pognoot,
There are questions (for the same driver) that keep coming time after time.
You will be happy to know that the same driver is simulated here (some members already there). How would it be for a double sub?! You will need power for these babies (~ 1300W each@6Ohms, 2600W@3Ohms for both RMS).
http://www.diyaudio.com/forums/subwoofers/231898-best-18-sub-folded-horn-enclosure-2.html
B&C S18H - Subwoofer - B&C Component Options - 18” Woofer – 18TBX100 8 ohm
B&C 18 TBX100 - www.usspeaker.com
B&C Speakers
Compare response with the specs of the Dynacord Cobra-Subs >30/32/38Hz@-10dB.
DYNACORD – Cobra-4 Systems
http://www.dynacord.com/downloads/cobra_katalog_en.pdf
http://www.dynacord.com/downloads/cobrapwh_datenblatt.pdf
http://www.dynacord.com/downloads/PWH28-EDS.pdf
Attachments
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Thanks, as a first-timer, believe me I'm trying to do my homework before posting questions. I am aware of the G-sub design and the designs on the B&C website. I need dimensions that will work for my needs, and one of these needs includes packing in the equipment truck. I have Yorkville TX8s for my tops which are 24" wide, so I want these to be the same width so I can stack the boxes.
So, it looks like I will need to come down in external height to 48". I'll increase depth to compensate.
My final design will look close to this dual chamber 2x18 but with straight vents. Clair BT-218
Thanks for the suggestions, I really appreciate it!
That is the best way to do it. If you are going to go through the trouble of building a box or boxes make sure they give you what you want. If it means moving to wards another brand of woofer to get the desired frequencies required, so be it. This is not a popularity contest, its what gets the job done based on your requirements.
Another thing to keep in mind if you are building quantity, xmax is irrelevant when you are using a large amount cabinets for you will attain the SPL needed with very little cone movement due to the coupling affect. You will not drive 8, 16, 24 Double Eighteens as hard as someone using 2 or 4 cabinets due to having a larger surface area.
If you build the cabinet right (Don’t be cheap) and have desired frequency response flat or –3 dB minimum, everything will fall into place. I made my first batch of Double Eighteens nearly 20 years ago and, they are still in service.
Hi, can you expand on what you mean by dance band? What instruments will you be mic'ing and what is the needed frequency extension? Most double 18 designs are intended for rock music, but several new designs have lower extension for EDM.
Certainly. We mic acoustic drums and run 5 stage synthesizers, one for Minimoog style synth bass. (Thriller!) We have (8) 18TBX100s currently mounted in (4) Yamaha SW218v boxes that have additional braces we installed to tighten them up. While the braces helped, the Yammy box itself is not very well made. Very hollow sounding and poorly braced to begin with. Well, to be fair....they are probably well made for the price point.
I measured the internal volume of the SW218v and port tuning, and loaded these parms into BassBox Pro 6 so that I can compare my new design. The sw218v is tuned to 35hz with a F3 of around 44hz. The larger internal volume of my new design tuned at 33hz nets a solid 3-4db gain from 30-40hz @1000w. The FR curve is much flatter than the SW218 box which starts to slope downward under 50hz.
All said and done, will this be worth the effort? I see two benefits-
1. the new design will go lower.
2. the new design will be considerably better built and will be more versatile for our setup.
I am going to try to have as much of the wood pre-cut as possible to where the majority of my work is in assembly. I’ll double up on the front baffle so it's 1.5" thick. Hope to have it professionally texture sprayed to match our TX8s as close as possible, still researching the best way to go about it here in the Denver area.
I measured the internal volume of the SW218v and port tuning, and loaded these parms into BassBox Pro 6 so that I can compare my new design. The sw218v is tuned to 35hz with a F3 of around 44hz. The larger internal volume of my new design tuned at 33hz nets a solid 3-4db gain from 30-40hz @1000w. The FR curve is much flatter than the SW218 box which starts to slope downward under 50hz.
All said and done, will this be worth the effort? I see two benefits-
1. the new design will go lower.
2. the new design will be considerably better built and will be more versatile for our setup.
I am going to try to have as much of the wood pre-cut as possible to where the majority of my work is in assembly. I’ll double up on the front baffle so it's 1.5" thick. Hope to have it professionally texture sprayed to match our TX8s as close as possible, still researching the best way to go about it here in the Denver area.
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Using Duratex paint with a texture roller you can match most commercial paint jobs yourself, for a small fraction of the price .
A 3-4 dB gain in just the 1/3 octave region from 30-40Hz is not going to make much audible difference.
In fact, when selling off a number of bass bins, buyers all preferred (and bought) cabinets with way less 30-40Hz but slightly more 60-100 Hz "punch".
Going to a tapped horn design can increase the output of your speakers by around 6 dB across the entire frequency range (even more in the upper "kick" range), though will take up more truck space than BR.
Eight of my single 18" Keystone subs would take up 26.5" of a standard USA straight truck, four wide, two high. I weigh 150 lbs, and can stack them two high by myself.
Going to truck box integers (regardless of the design chosen) will make a difference in loading.
Typical USA straight trucks have 90 x 90 inch boxes, so 45, 30, 22.5 inch are optimum packing dimensions.
The Keystone is 45 x 22.5 x 26.5 inch wide.
The 26.5" width was done as a match for some existing top cabinets, but is wider than your top cabinets.
At any rate, your larger dual 18" will be roughly equivalent in output to a JBL dual 18" SRX728, by going to a TH design you could parlay your 8 cones to the equivalent output of eight SRX728.
That would be a quite a difference.
You would also use only 1/4 the power to achieve the same SPL level you now reach (and have response to the low 30 Hz range).
In the real world of night clubs with less than perfect AC power, that can translate to a huge SPL difference.
Art
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Sounds like this BR project won't be worth the effort then, at least with the current drivers that we have and the desire to stay within the 2x18 BR design. Thanks for you help, I appreciate everyone's input.
While I respect Art's experience, I don't alway agree with his opinion. This message board in particular is obsessed with tapped horns as being the only solution, while in the real world they only make up a small fraction of PA systems, for good reason. The only thing tapped horns have going for them is efficiency/sensitivity, for which they make huge compromises in box size, extension, phase shift, and bandwidth. Not to mention, I have never heard them sound good.
The type of low extension bass reflex design you are interested is what they are using for big time EDM/dubstep music, with extension below 30hz:
Meyer Sound News : Meyer Sound LEO Supercharges Bassnectar Tour (with Video)
1100-LFC : Low-Frequency Control Element
http://www.meyersound.com/sites/default/files/1100-lfc_ds.pdf
SKRILLEX Train Tour Chugs Along with PK SOUND - PK Sound
CX800 - High Powered Subwoofer - PK Sound
http://www.pksound.ca/wp-content/uploads/2013/03/CX800-FINAL-Web.pdf
You should have no problem mimicking these designs.
Hi,
How about this thread: http://www.diyaudio.com/forums/subwoofers/213685-bass-my-soldier-10.html , Post #94. Take two and mount one upside down? One box is 22"W x 24"H x 28"D, so you could add a little more width to it. You could pm the OP to see how he liked the end result.
Regards,
How about this thread: http://www.diyaudio.com/forums/subwoofers/213685-bass-my-soldier-10.html , Post #94. Take two and mount one upside down? One box is 22"W x 24"H x 28"D, so you could add a little more width to it. You could pm the OP to see how he liked the end result.
Regards,
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