Cabinets that can handle octave and subharmonic effects?

No, it's not just speaker size. Sorry.

Yes, a cabinet with 10-inch speakers can handle low frequencies. If you have the power to drive them, Acme Low B cabinets can shake the earth; I have a pair of 2x10" Acme Low B2's that are the bees-knees when driven properly.

 

For true sub harmonic power I'd go with the Whappo Grande from Accugroove.

 

A folded horn DIY cab would probably work. Like the ones here http://www.billfitzmaurice.com
Is the 2x15 cab sealed or ported? You could get away with using the 2x15 if its sealed, but your speakers will probably get damaged if its ported and you're cranking it.

 

My DBX 120a sub-synth produces fundamentals in the 26 ~ 55 Hz range.

You will need a vented box tuned very close to 26 Hz, for starters. Next, you will need a Godzilla power amp, because the drivers that will hit 26 Hz are very power hungry. Those that are not power hungry run in HUGE cabinets. No free lunch at 26 Hz.

My Rockford RFR-2215 subs fit the bill for the above requirements. Each 15" requires 500w to reach full power. At 500w, they don't make much noise at all, but they do go ALL the way down.

Each of my 1x15 subs is 7.9 cubic feet external volume. Two of them will do the sub-synth job inside a bar. The pair of 1x15 is nowhere close to sufficient when used outdoors. I need at least four for this, and a pair of PLX-3002 amps to drive them.

Knowing all this, the low/loud/efficient solution is building a pair of Tuba36 Slims with Magnum 15LF drivers. The 116" horn path length provides a cutoff frequency of 28 Hz. Going down this low requires a lot of mouth area (multiple cabs) or pointing them into a corner. The practicality of hauling these big monsters is something else. Consider making the Slim version in 28" width instead of the standard 30" width. This will let them ride two-up in a standard 5x8 cargo trailer.

I understand each T36 Slim uses about 3.5 sheets of 3/4" 4x8 plywood, and the completed box is estimated to weigh about 200 pounds. If you want to play at sub-synth ranges, this is the ticket.

None of the above is a trivial financial undertaking. I'd make damn sure of the need to do this before investing the cash. You might find out you really hate the sound. I use mine very sparingly.

 

funny,

just be careful you're NOT using any of those subharmy effects. andy says its a no-no w/ his cabs.

 

My initial thought would be a Bergantino NV215, but actually a Bag End ELF subwoofer system might be the way to go.

 

Interesting. Any reason why?

I've used octave with the B2's, and it sounds great. Then again, I'm using it only slightly blended in, not full on. More as an effect.

Never used a BBE/Aphex unit with the Acmes.

 

I think that the Bergie 610 has tons of lows, I use subharmonics sometimes and it handles em fine. An Aguilar 412 is another option as well. For ultimate bass, the Bag End ELF is the way to go, but its a bit pricy. Speaker size can help identify whether a cab can handle more lows, but there are many exceptions and an old 215 usually doesn't have enough lows. Maybe look for 2 118s, like that SWR cab, or possibly a 218 if you find one, but I have not seen any new 218s made for bass, only PA. I know Madison makes a 21" speaker as well, but not sure how good it is for bass or what cabs they have for it.

 

Acmes are tuned for 31hz. They drop off very rapidly below that according to Andy and cannot handle these frequencies with a lot of power behind them. I asked him if he thought a B2 could handle a 5 string tuned to A and he advised to attempt it at anything louder than a whisper.

 

There used to be a pro-audio shop near me where my salesguy was (a) a bassist, (b) an audiophile freak, and (c) happy to wire up everything in the shop just to audition and compare. I was asking him similar questions, and he got busy and wired up a Bag End ELF system with a stack of Crown amps (it's a shop, after all) and every configuration of Bag End cabs they had: 2x10, 4x10, 2x12, 1x15, 2x15, and some folded-horn amphitheater monstrosities. Then he hauled out his bass, and a full-range test CD, and we auditioned.

Holy shi-cow, the whole building was vibrating in a scary way when we hit those low, almost sub-audio notes. Even with the smaller cabs, and even at moderate volume, the bottom end presence was massive. Then we took the ELF processor out of the loop and ran the amps direct into the cabs. There was enough volume and low end for most PA purposes, yes. But the utter earth-moving depth, the air moved at the very bottom of the audio spectrum, was not there. And the cabs sounded too flat.

It took the biggest of the cabs, at high volume, without the ELF processor, to put out low end equal to a smaller array _with_ the ELF unit. If you're doing indoor club gigs, I would say sinking the dough into the full ELF system will get you shockingly low frequencies in a portable package. A 2x15 in that context would be just fine. But without buying into the whole processor system, the Bag End cabs by themselves are just sterile-sounding and inefficient.

 

Another suggestion: use a high-pass filter or parametric EQ to cut the ultra-low frequencies (say, everything below 30 or 40 hz) so you can get the beef without destroying your speakers. You will still get a big sound and won't be using a lot of amp power. Also, maybe compression (especially multi-band, where you could limit just the low frequencies).

I use 12" speakers (EA Wizzy and Bergantino HT-112s) that sound big for their size but don't go incredibly deep. I love filters, octavers, fuzz, and synth effects. The Fishman Platinum Pro Bass EQ pedal has an adjustable filter and one-knob compressor that help keep the low lows in check. Kinda a different perspective than the other posts.

I've done sound on a 20 Kwatt Bag End ELF system, and I'll agree: there's nothing like the incredibly deep, speedy punch of those sealed subs fed with the proper power.

 

The problem with using ported cabs for these super low freqs is IIRC getting to a certain point below the cabs resonant freq causes the backwave of the speaker, instead of RESISTING cone movement and helping damp the speaker and preventing it from bottoming out, the phase of the longer lower wavelength at some point ends up REINFORCING the speaker motion instead of resisting it. End result being LOTS of excursion with very little power required. But if you're running lots of power at that freq, you've really got lots of problems.

Its the "explosive diarrhea" version of normal "speaker farting".

Randy

 

Cool, that makes sense. I appreciate that.

 

Sounds like the old Bose 801? pa speakers. They sounded good with the special Bose EQ, but not so good with stock PA. Totally different effects going on, but sort of the same idea. Design an electronic circuit that compensates for the shortcomings of the speaker/cab combo.

It looks like a pretty cool idea, actually. You use electronic circuit to compensate for the peculiarities in the cab response below the res freq. Bingo, you get very flat response. The theory is pretty sound. Just worried about power/excursion limits on the speakers. The principle would work up until the point the speakers self destruct. The lower in freq you go, the more power you need, 12dB /octave adds up VERY Fast, you'd need an awful lot of power to get even an extra octave out of this. 3dB=2x the power. 6dB=4x. 9dB=8x. 12db=16x. So if you need 100W at 80Hz to produce reasonable volume, it will require 1600W at 40Hz to match that volume.

So once again, there's no free lunch....

Randy