Looking for ideas on the best subwoofer designs that can be stacked together in a cluster with the frontal area of 8x8 ft max or smaller. Depth doesn't matter a whole lot. Thinking a total of 8 or 16 cabinets, prefer tapered horn, open to all other styles. Powered by 4x amplifiers that are optimized for 4 ohms at 3500w x2 or 5600w x1. Need a solid output down to approximately 20 Hz and max SPL for electronic music. Easily maintainable in USA drivers. Can either assemble a flat pack, or build from scratch, or buy complete.
20 Hz is illusional in mobile PA and with, whatever this is, max SPL. Even 30 Hz is extremely low.
Booger_weldz : might have to build something like that, just exploring the options, was hoping to find already selected drivers and a proven design.
Turbowatch2 : plenty of bass music goes down to 20 Hz, many established subs work well for 20-30 Hz, and "max SPL" means squeeze as much as possible.
Maxolini : both Keystone and TH18 have a larger frontal area than a 2x2, so unless someone can suggest PA drivers that are like 4 ohms at 1500-1700 wRMS or higher to accommodate a cluster of just 8 subs, those cabs prolly won't work for this purpose with those specific amps --- I already have 16 horns loaded with 8 ohm 800 wRMS drivers (run 2 per channel) that peak at 50-80 Hz at 105 db (1w/1m) and work fine down to 30 Hz at 90 db and 20 Hz at 75 db with overall 137 db cont or 143 db max (each cab) --- they just have too large of a frontal area to fit 16 into the stated dimensions and I haven't been able to figure out 4ohm-1600wrms replacement PA drivers that would work to reliably run only 8 cabs plus also would be nice to improve the low corner below 40 Hz.
Mayhem13 : all subwoofers are a compromise of "win some loose some", with that said, for this particular use case, I don't care about achieving an even coverage area and I actually like having the power alley, my main goal is to fit the stated 8x8 ft (or smaller) dimensions while fully utilizing the power of the 4 amps mentioned in the first post and get as much bass as low as possible, I'm open to all other suggestions or ideas, also wouldn't mind learning more about the mentioned "modes" if there's any additional info to digest and consider.
Turbowatch2 : plenty of bass music goes down to 20 Hz, many established subs work well for 20-30 Hz, and "max SPL" means squeeze as much as possible.
Maxolini : both Keystone and TH18 have a larger frontal area than a 2x2, so unless someone can suggest PA drivers that are like 4 ohms at 1500-1700 wRMS or higher to accommodate a cluster of just 8 subs, those cabs prolly won't work for this purpose with those specific amps --- I already have 16 horns loaded with 8 ohm 800 wRMS drivers (run 2 per channel) that peak at 50-80 Hz at 105 db (1w/1m) and work fine down to 30 Hz at 90 db and 20 Hz at 75 db with overall 137 db cont or 143 db max (each cab) --- they just have too large of a frontal area to fit 16 into the stated dimensions and I haven't been able to figure out 4ohm-1600wrms replacement PA drivers that would work to reliably run only 8 cabs plus also would be nice to improve the low corner below 40 Hz.
Mayhem13 : all subwoofers are a compromise of "win some loose some", with that said, for this particular use case, I don't care about achieving an even coverage area and I actually like having the power alley, my main goal is to fit the stated 8x8 ft (or smaller) dimensions while fully utilizing the power of the 4 amps mentioned in the first post and get as much bass as low as possible, I'm open to all other suggestions or ideas, also wouldn't mind learning more about the mentioned "modes" if there's any additional info to digest and consider.
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Is this going in the back of a truck? 🙂
Sounds similar to some design ideas I was playing around with a few years ago, when I was looking at all the music trucks during one of our Carnival, where they had all the speakers hanging off the end of the trunk, usually a flatbed type, and I was thinking that what if it was possible to use the space on the flatbed a bit better for bass reproduction, without resulting in the precarious tower of speakers hanging off the back ...
Have a look at manifold designs for some inspiration. Another approach might be a single-fold TH, so the 2x2 frontal area for each subwoofer is almost all mouth (see illustration below) Just bear in mind that there are going to be bandwidth limits to contend with (usually something around 3*Fb, so a sub designed to reach 20 Hz will likely be unusable above 60 Hz).
Very few "PA" oriented subs are designed to work well that low, since four times the displacement (excursion) is required for each halving of frequency to maintain the same level. This basically means you need four times the truck space for the same output at 20 Hz as 40Hz.
Since ~4dB change in level sounds around half as loud at 20Hz, saying a -30dB response "works fine" begs the question of what output level you want.
Tapped horns output are basically unusable below the lower impedance minima/ Fb, when response drops at ~24dB per octave. The Fb is ~ 4 times the horn path length.
Even if the Keystone or TH18 fit your dimensional requirements, they are nearly an octave short of 20Hz response.
A FLH works as a direct radiator below it's FC (also the 1/4 wavelength), so can be equalized for response down low.
That said, if your FLH use 15" drivers with around 8mm Xmax, all 16 cabinets at maximum output would only hit around 120dB at 20Hz.
One single driver tapped horn similar to the Danley Sound Labs DTS-20 design could provide near that level of output at 20Hz.
The mouth could be located on the small end of the cabinet.
Using a 22.5" or 24" mouth would allow 18" drivers to be used, 16 cabinets fitting in an 8'x8' cluster.
Or a design like a split TH-221 would allow nine cabinets in a 90"x90" frontal area.
Josh Ricci's Gjallarhorn would also be a good option, with plans readily available.
4 Gjallarhorn cabinets would be a 90"x90" frontal area, 138dB 20Hz/1meter using 112.6volts.
Anyway, plenty of options.
Art