Suggestions Creating Subwoofer Box(s) - 56 cuft available

[2MuchRiceMakesMeSick]

Hi 2MuchRiceMakesMeSick,

Post #19: "... Is there any way I can drop the height to 14"..."

Yes, that sound quite feasible. I haven't done a drawing on this one yet, but of the top of my head that would be a good height. You would be looking at a combined front face of 76"W x 14"H; the overall depth would be 80"D; the individual boxes would be 76/4 = 19"W.

I can see if I find the time to draw something up around those dimensions, if you are interested.

Regards,

That would be greatly appreciated.

This is the space I have available.

Anything in white I can use. Any area in green will be covered up and I cannot put anything in front of it.

 

[weltersys]

Right now I have 4-6.5 tang bands in a TH configuration but it is just not near enough (SPL or frequency depth) for my taste.

From four 6.5” Tang Bands to eight Epic 12", like going from a skateboard to a semi truck .

To get full output from the drivers will require 4000-10,000 watts.

What are your amplifier plans?
Is your house wired with 10 gauge?
What top speakers are you using?

 

[2MuchRiceMakesMeSick]

I havent bought the power amps yet but I plan on using pro audio QCS amps. 4k minimum should not be a problem. House has dual 12 gauge breakers. Mids and highs is 10 Hiquphon tweeters, 10 seas excel 4.5" and 10 7" seas excel drivers for a total of 30 drivers.

Right now I am more concerned with the box(es) that i will be using to house the 8-12"s that fit within my space.

 

[tb46]

Hi 2MuchRiceMakesMeSick,

Here ist a drawing for the 14"x19"x80" box. I did not work out the access panel detail, but otherwise everything is there. The frequency response shifted up a little bit, as the drawn dimensions are a little different from the first rough try at it, you also gain a few dB.

Let me know what questions pop up.

Regards,

 

[tb46]

Hi 2MuchRiceMakesMeSick,

As to the power requirement, according to Hornresp you will exceed the Xmax slightly @ 23Hz w/ 900W into 8 Ohms. Hornresp does not account for compression or losses, probably you'll be able to easily drive 1000W into one of these boxes (that's for two drivers). Always approach power limits carefully, I recommend against high power sine wave testing. You will need low-cut and high cut filters.

I'll attach the Hornresp displacement and SPL graphs. For me one of these would be plenty.

Regards

 

[2MuchRiceMakesMeSick]

Very nice and thank you very much.
How did you create the PDF? Did hornresp do that?

Just for comparison can you give me one on 3 or 4 RE XXX 15's (80 x 76 x 15-16)? I have one of these in my car and it is the best sub I have ever heard.

Electrical Q Value -Qes: 0.58
Mechanical Q Value -Qms: 3.62
Total Speaker Q Value -Qts: 0.501
Free Air Resonance -Fs: 19.10 Hz
Equivalent Compliance -Vas: 207.0 liters
One-Way, Linear Excursion -Xmax: 54 mm
Efficiency -SPL 1W/1m: 85.81 dB SPL
Effective Piston Area -Sd: 810 cm^2
DC Resistance -Re: 4.2 ohm
Nominal Impedance -Znom: Dual 2 or 4 ohm
Thermal Power Handling -Pe: 2000 W
Force Factor -Bl: 18.16

Mounting Depth - 13.5 inch
Mounting Hole Diameter - 14.5 inch
Overall Diameter - 16 inch
Bolt Hole Circle - 15.25 inch
Motor Width - 10.5 inch
Motor Depth - 5 inch
Basket Depth - 8.5 inch
Displacement - 0.27 cu. ft.
Weight - 76 lbs.


Thanks again WOW. That is outstanding!

 

[tb46]

Hi 2MuchRiceMakesMeSick,

I do my drawings in AutoCAD, and print from there to PrimoPDF for the output. The whole thing is actually quite time consuming, so I'll have to wait on finding the extra time for the Re XXX 15; I quickly entered it into Hornresp, and I'll attach what I came up with. Hornresp has the volume @ 362.4 L_net (v. 266.6 L_net for the 14x19x80 Epic 12), so you're looking at substantially bigger boxes. Maybe you can find a link with at least a dimensioned side view drawing for this new driver; without that it basically not possible to draw this, and without a reasonably accurate drawing you won't know how much space this one needs.

Regards,

 

[Josh Ricci]

The XXX's except for the 12" do not like horns, tapped horns or pipes really. Also they are extremely problematic to fit and design in with the weight being near to 80lbs and the depth on even the 12" being 13". Yes it is deeper than it is wide. The motor is 10.5" diameter as well. Then there is the extra long excursion which must be cleared on the throat side and the fact that the MMS is high and coupled with the displacement available creates extremely high forces on the cabinet baffles and walls at low frequencies which requires extensive bracing. I had an interesting double 12" XXX TH design but I aborted mission after trying to fold it and make it actually buildable. It was a nightmare.

Try TC LMSR series or the previously mentioned Epic's are good for deep extension. Alpine Type R 1223 or 1243 in multiples can be great as well.

 

[2MuchRiceMakesMeSick]

cool, im glad I checked on this forum before buying. I am going to get the epic 12"s.

Now for power. In my experience 100 watts of car or even home audio (consumer) is not the same as pro audio.

An example is, I have an 130wrms pioneer SC-57 that barely powers my tang bands (100wrms). I recently purchased a measley '90w rms' qsc amp and I cannot turn the gain up more then 5-10% before bottoming out the TBs.

Will these subs really handle 500w rms of pro audio QSC amps?

 

[bjorno]

Hi,

FYI,

Here is a suggestion of a T-TQWT variant that have low enough Gldy at 80 Hz, thus there is no need for signal-delaying the mains to integrate well:

b

 

[tb46]

Hi bjorno,

The way I understand the OP, he wants very low bass for HT, and is very specific about the space requirements, including where to vent the boxes (Post #21). Naturally, when you shorten the length a lot of nice things happen (to a point) .

Regards,

 

[weltersys]

An example is, I have an 130wrms pioneer SC-57 that barely powers my tang bands (100wrms). I recently purchased a measley '90w rms' qsc amp and I cannot turn the gain up more then 5-10% before bottoming out the TBs.

Will these subs really handle 500w rms of pro audio QSC amps?

I have not used the speakers you are planning to use, but I have tested lots of Lab 12 speakers with 400 watt sine waves (49 volts) with no damage, and (accidentally) put 120 volts of 60 Hz (about 3600 watts) into a BC18SW115-4 for several seconds three times in a row.
Josh Ricci has pushed (and occasionally exceeded) the level of speakers, but his testing shows the TC brand doing quite well at rated power.

Most amps do not perform well if voltage drops, at very high peak power (like 4000 watts output using 10 gauge wire) the peak may be reduced as much as 3 dB.

Input gain and potentiometer taper on pro amplifiers varies considerably, "5-10%" may be full output, or even clipping the amp.
Clipping an amplifier can result in a 3 dB (double the power) or more increase in average power.
Amps sound different when clipping, some amps clip softly and basically sound compressed, others make a sub sound like it is "bottoming out" or flapping.
I re-tested a small tapped horn that I had thought to be rather marginal with one amp with another, and found it was the amp, not the speaker that sounded bad as soon as the clip lights illuminated. The other amp allowed another 6 dB of usable peak output, even though rated for less than 3 dB more output.

Some pro amps use lots of current limiting (2 ohm output less than four ohm output) some use very little, which can completely change the way a sub with a few narrow low impedance dips sound.

When it comes to real speakers and music, amp ratings do not tell the whole story.
P.S. There are some QSC amps that sound quite good on bass, and some that don't, though that can be said about Crown and Crest too.
For low impedance, super efficient good sounding LF output, good $ to watt ratio, hard to beat Brian Oppegaard's SpeakerPower SP-4000.
Brian learned quite a bit over his years at QSC, and from his relationship with ICE.

Art Welter

 

[bjorno]

Hi,

FYI: Just posting a HR script of the picture in post#30:

b

 

[2MuchRiceMakesMeSick]

Hi 2MuchRiceMakesMeSick,

Here ist a drawing for the 14"x19"x80" box. I did not work out the access panel detail, but otherwise everything is there. The frequency response shifted up a little bit, as the drawn dimensions are a little different from the first rough try at it, you also gain a few dB.

Let me know what questions pop up.

Regards,

I started looking at this today and long story short I need to build this strong so that it supports a mattress on top (150 lbs) me (200 lbs) + two girls (100 lbs each)

Is it possible to shorten the 19" width of the box by 1.5" (2 x 0.75) to help support the weight? any other suggestions to make this box strong to support the weight?

 

[tb46]

Hi 2MuchRiceMakesMeSick,

"...possible to shorten the 19" width of the box by 1.5" (2 x 0.75) to help support the weight? any other suggestions to make this box strong..."

No problem to reduce the 19" dimension to 17.5". It actually smoothens out the response a little bit more. If you build the boxes from a decent quality plywood, and if you build the bracing as shown they should be plenty strong enough. Naturally, that depends somewhat on the usage.

Regards,

 

[head_unit]

I like QSC-good products from nice folks. As with all brands products range from highly sophisticated-QSC - PowerLight3 Amplifiers-to nice but more ordinary. Just beware that many pro amps run nondefeatable fans. Even with variable speed, these cannot be used in a really quiet room, they have to be put elsewhere.

If you really want the "best" sound quality, consider a sealed design. That just has the simplest transient response, period. All other designs exist to further other goals, generally increasing low frequency sensitivity and/or maximum SPL, plus maybe reduction of distortion at those frequencies. All the other designs incur worsened transient response, and if you look at the frequency response of the horns there are all kinds of response spikes. Above the passband they might be, but horn shapes are generally compromised for practicality. Ported or horn may "outperform" the sealed, but you have a lot of space and a big budget, so optimization is not a big concern.

I love horns, but if I had your application I'd probably consider just a wall of subwoofers loading each other. Maybe manifold-style a la Electro-Voice, or a slot-loaded kind of thing.

Plus, if you want very very very low frequencies without building your house around a horn, sealed may be the only way to do that. Ports big enough to tune down to like 10 Hz or something will probably have their own resonances.

 

[tb46]

Hi,

I updated the drawing:

Regards,

 

[2MuchRiceMakesMeSick]

Thanks for the update.

I was thinking about building 2 boxes (4 woofers) in the 80" version and the other 2 in the 64" version.

Any problems in doing this? Suggestions on why I wouldnt do this?

 

[tb46]

Hi,

This is something you almost have to try out yourself. I would recommend to stay with one length for all four boxes. But, it may well work (it may even work well). I don't think you can easily simulate what this will do in your room with your specific enclosure location. I'll attach the-hastily done-comparisons of SPL and phase.

Regards,

 

[2MuchRiceMakesMeSick]

I may just build 2 of each and test them. Then built another 2 of the ones I like the best. Is there any way I can get you to update the drawing with the shorter box design?