Hello, my band (rock cover) is looking to downsize our rig and I am looking for plans to build a pair of compact subwoofers that will provide similar or greater low end output to my current setup.
We are currently running a crappy (and massively heavy) JBL JRX setup with two JRX225 tops and four jrx 118s subs. We generally run just 2 of the subs in smaller bars and 4 for outdoor shows.
Here are the specs on the subs
http://www.jblpro.com/ProductAttachments/JBL_JRX118S.PDF
There is such a myriad of information here that I am having trouble digesting it all and am hoping you can help me select a plan. I am open to any design but am really liking what I am seeing from some of the tapped horn plans.
Here are some general requirements.
1. Plywood construction to save weight
2. Around 2ft cubed
3. Driver selection around $150.
4. Design that will work well without corner loading (We rarely run in to a situation where we can corner load)
5. PA tops will be crossed over around 100-110.
6. Ability to play bars with two subs with the option to build more in the future for larger shows.
I have been reading a little on the THAM12 and am wondering how these will compare to my current subs. The drivers for the tham12 are a little out of my price range however.
Can someone give me recommendations on a plan/driver?
Thanks and greatly appreciated!
We are currently running a crappy (and massively heavy) JBL JRX setup with two JRX225 tops and four jrx 118s subs. We generally run just 2 of the subs in smaller bars and 4 for outdoor shows.
Here are the specs on the subs
http://www.jblpro.com/ProductAttachments/JBL_JRX118S.PDF
There is such a myriad of information here that I am having trouble digesting it all and am hoping you can help me select a plan. I am open to any design but am really liking what I am seeing from some of the tapped horn plans.
Here are some general requirements.
1. Plywood construction to save weight
2. Around 2ft cubed
3. Driver selection around $150.
4. Design that will work well without corner loading (We rarely run in to a situation where we can corner load)
5. PA tops will be crossed over around 100-110.
6. Ability to play bars with two subs with the option to build more in the future for larger shows.
I have been reading a little on the THAM12 and am wondering how these will compare to my current subs. The drivers for the tham12 are a little out of my price range however.
Can someone give me recommendations on a plan/driver?
Thanks and greatly appreciated!
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Check out Bill Fitzmaurice subs they are lightweight and truly amazing. Went to a gig in a huge field with just one of his 12" powered Titan subs the bass was powerful, clean and tight no matter where I stood in the field.
I'm gearing up to build a couple for myself. Good luck in your search.
I'm gearing up to build a couple for myself. Good luck in your search.
the way i see it you can't get any more compact then these br boxes.
you could put a high power 18sound/b&c driver in if you have the amps to feed them.
hofman's iron law, pick any two of loud ,low and small.
you could put a high power 18sound/b&c driver in if you have the amps to feed them.
hofman's iron law, pick any two of loud ,low and small.
Thank you for the replies. mdross, I was initially running a set of Bill Fitzmaurice OTOP12s and a single Titan 48. The sub was just too damn big to fit in any of our gigs and we never ran in to a situation where we could corner load it. It was extremely loud but never produced much of a thump from the kick drum. (of course this may have been user error)
m R g S r, That cs-30 design looks sweet and easy to build but wouldn't I get much greater output from a horn design? I would be willing to go with a little larger box than those guys.
I did a little more reading last night and jbells ss15, or a tham15 look very cool. That would be about as big as I would want to go as a pair.
I have built a handful of BFM designs in the past and am very happy with them, I wouldn't mind trying something different this time around though and am wondering how a TH design would work for us.
I am going to be using two 4x6 BFM SLA Pros and two 2x6 BFM SLA Pros for smaller shows and am planning on adding another set of 4x6 for larger outdoor stuff. I am basically looking for something a little different that will scale well with that setup.
Like I saying earlier, I would like a portable sub that would work well as a pair of 2 indoor for bar shows up to 200 people and would scale well for future outdoor shows in stacks of 4,6,8 etc.
Thank you again for the help, I have been reading for days here but need a little direction since there is so much great info here, it is hard to take it all in.
m R g S r, That cs-30 design looks sweet and easy to build but wouldn't I get much greater output from a horn design? I would be willing to go with a little larger box than those guys.
I did a little more reading last night and jbells ss15, or a tham15 look very cool. That would be about as big as I would want to go as a pair.
I have built a handful of BFM designs in the past and am very happy with them, I wouldn't mind trying something different this time around though and am wondering how a TH design would work for us.
I am going to be using two 4x6 BFM SLA Pros and two 2x6 BFM SLA Pros for smaller shows and am planning on adding another set of 4x6 for larger outdoor stuff. I am basically looking for something a little different that will scale well with that setup.
Like I saying earlier, I would like a portable sub that would work well as a pair of 2 indoor for bar shows up to 200 people and would scale well for future outdoor shows in stacks of 4,6,8 etc.
Thank you again for the help, I have been reading for days here but need a little direction since there is so much great info here, it is hard to take it all in.
Thank you for the reply! We play modern rock / country and don't really need to go down to 30hz. We run our kick mic through a 31 band eq and roll everything off below 50Hz.
I am willing to go with a bit larger box than the BRs as long as the footprint is about the same size. Height really doesn't matter, we just run in to some situations where our old T48 will just not fit.
Am I going down the wrong path considering the ss15 or tham15? Does anyone know how these will compare to the 18" BRs I am running now?
Thank you again for the assistance!
I just built a dual 12 th box that has a 15.5 by 19 footprint that while I tuned it to 35 you could shorten the path to get more 45 and up. Each box handles 1000 watts and the 12 inch drivers cost between 60-100 each. Best bang for buck and especially footprint that I've found.
This is me sliding the horesp sliders to make the design I came up with shorter and slightly wider for a 45 Hz tune. Shown is where I would limit with live music -->transient limit of 75 V should be safe considering the music dynamics being played (staying within mechanical excursion even this high) as 63 V would be my RMS limit for sine wave EDM.
See picture for max power output (single 185 L internal cab translates to roughly 8.4 cu ft external)
Message or respond and I'd be happy to share more about the design. You're looking at 130+ dB from 42- 52 Hz and >127 dB in the trough around 80 which can be eq'ed and may not be as bad as it appears.
Note this is limited to 75 volts per cabinet and assumes the two 8 ohm nominal drivers are parallel.
This is me sliding the horesp sliders to make the design I came up with shorter and slightly wider for a 45 Hz tune. Shown is where I would limit with live music -->transient limit of 75 V should be safe considering the music dynamics being played (staying within mechanical excursion even this high) as 63 V would be my RMS limit for sine wave EDM.
See picture for max power output (single 185 L internal cab translates to roughly 8.4 cu ft external)
Message or respond and I'd be happy to share more about the design. You're looking at 130+ dB from 42- 52 Hz and >127 dB in the trough around 80 which can be eq'ed and may not be as bad as it appears.
Note this is limited to 75 volts per cabinet and assumes the two 8 ohm nominal drivers are parallel.
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^^^^^^^^^^ that's the point.
You can't beat Physics Laws. 🙁
1) The subs you already have are as small as can be, just a couple inches wood around the speaker frame edge.
2) the *excellent* Danleys, are smaller mainly because they rely on a single 12" instead of a single 18" (which has about twice the cone sirface) .
Is there a price to pay for that?
Yes, they are "maximum 121 dB SPL , 127dB Peak" (hmmm, peak is 3 dB more, not 6 dB 😕 ) while the JBL is 133dB Peak, 6 dB (4X the power) louder than the smaller Danleys.
In practical terms, you'd need at least 2 Danleys to match 1 JBL .... where's the weight/space savings?
3) I guess that one practical way out of this is to basically clone the JBL you already have, but with new lightweight thin and braced plywood cabinets .
I have built very light touring cabinets out of 10mm , slightly over 3/8" plywood😱, go figure, but used a lot of bracing, and reinforced it at critical points with fiberglass/resin strips.
And use modern good very efficient, lightweight NEO drivers (I use Faital because they are widely available here in Argentina) .
You will cut weight almost by half ... and improve sound 😀
FULLY agree with cutting everything below, say, 50 Hz in a portable, live environment.
Thanks for the reply JMFahey,
I was rushing a bit with my initial post. As far as weight is concerned, I would like to keep the weight under 75lbs. As far a size, I am more concerned with footprint. I can go with a taller cab.
I do like your idea of trying to experiment building the existing jbl cab out of lighter material.
Thanks again.
I was rushing a bit with my initial post. As far as weight is concerned, I would like to keep the weight under 75lbs. As far a size, I am more concerned with footprint. I can go with a taller cab.
I do like your idea of trying to experiment building the existing jbl cab out of lighter material.
Thanks again.
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1) Agreed
2) The JBL specs use an inflated peak response, if you take the recommended amp amp power of 700 watts, the JBL JRX 118S only produces 124.45 dB (96 dB sensitivity + 28.45 dB).
In post # 1492, “Single sheet TH challenge”, Crescendo measured his 3015LF loaded, 1/2” Aruco plywood SS15 cabinets outdoors: 70Hz: 103.2 dBC, 2.83 v at one meter, 70Hz, 124.7dBC, QSC PLX3402 amplifier “just at clip” (about 75 volts, 700 watts at 8 ohm). Had there been a linear voltage in/SPL out relationship, 700 watts/75 volts would have resulted in about a 28.5 dB increase in SPL, 131.7 dBC.
131.7-124.7 = 7 dB of power compression. (-6.4 dB at 55Hz, -5.2 dB at 50Hz) so actual measured response would likely be little more than the JBL JRX 118S.
It is likely that the SS15's floppy 1/2" construction is responsible for the upper reduction, somewhat counter intuitively, wall deflection saps upper frequencies more than LF.
Art
Hi Art (weltersys),
Do you have any thoughts on the power compression in the JBL JRX 118S? Also, the ports don't look big enough to support the low end. Maybe that's where a SS15 style box would have an advantage, big port and better cooling.
Hi KTOKTO,
If we are talking about building new, light weight enclosures how about a SS15 style for the JBL 18" drivers just to try? That way we could get an apples to apples comparison. May be worth the trouble. Could you measure the T/S parameters of one of the drivers?
Regards,
Do you have any thoughts on the power compression in the JBL JRX 118S? Also, the ports don't look big enough to support the low end. Maybe that's where a SS15 style box would have an advantage, big port and better cooling.
Hi KTOKTO,
If we are talking about building new, light weight enclosures how about a SS15 style for the JBL 18" drivers just to try? That way we could get an apples to apples comparison. May be worth the trouble. Could you measure the T/S parameters of one of the drivers?
Regards,
Thank you for the replies everyone. Based on what I am reading, I think I will just stick with the JBLS for our small indoor shows since I will not be gaining much without increasing greatly in size and just build something at a later date for large outdoor shows next year. Thank you.
The two I'm building are BFM Table Tuba's 30" square or stand them up for 20" x 30" footprint each with 12" driver. For inside use they are overkill but better to have it and not need it as they say.
I think that's a good decision... While you are thinking about it, maybe there are some ways to improve load in/out. If you are just lugging them cabs a nice hand truck might be a big help.
When I was in the business my amp box and spare gear box both had wheels. Would set a speaker on each box to move them around. Most times had another body to help me otherwise there was always someone to give me a quick helping hand.
Not really, other than the JBL's recommended power is 350-700 watts using a 3" coil would make me think that it should not see a lot of power compression at that level. One would have to measure it to see if the power compression is as bad as the SS15.
Art
I have ample experience with the jbl prx 518 (2044e loaded). Im trying to track down the specs for it right now.
IF the specs of the 2043g are similar to the 2044e then i would expect extremely similar results as far as output and extension.
My "mini othorn" design
http://www.diyaudio.com/forums/subwoofers/254752-oth40c-15-loaded-compact-th-flat-40hz.html
Smacks the CRAP out out of the prx518s, in both output AND extension (handily in extension) in a very similar form factor (slightly bigger).
A high quality 18" driver (18 sound, faital pro, BC) in a *slightly* larger enclosure offers great output advantage and extension advantages (te larger youcan go, the more extension you can garner) IF youcan supply more power.
IF the specs of the 2043g are similar to the 2044e then i would expect extremely similar results as far as output and extension.
My "mini othorn" design
http://www.diyaudio.com/forums/subwoofers/254752-oth40c-15-loaded-compact-th-flat-40hz.html
Smacks the CRAP out out of the prx518s, in both output AND extension (handily in extension) in a very similar form factor (slightly bigger).
A high quality 18" driver (18 sound, faital pro, BC) in a *slightly* larger enclosure offers great output advantage and extension advantages (te larger youcan go, the more extension you can garner) IF youcan supply more power.
Why use a "quasi 3 way" with a Sub???
The whole reason for the Quasi 3 way is to get by without a Sub. Does that bottom 15" do anything?
The whole reason for the Quasi 3 way is to get by without a Sub. Does that bottom 15" do anything?
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