Lab 12 Domino DFLH

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The Domino DFLH was named for the tall thin cabinet shape and design, the project came about from a desire for more punchy low frequency using less power than ported cabinets,yet taking up similar volume and tall enough to elevate top cabinets. In the Hornresp simulation it appeared that a tall long FLH (front loaded horn) could fit in the available trailer space and still give decent 40Hz response. The entire sound system fits in a small trailer which would be completely filled by a pair of LabHorns. yet the compact single 12” subs give the much larger subs a run for the money.

Bass response initially was absolutely terrible when first tested, though became better when the speaker was screwed down (duh...) but still was poor compared to the Hornresp simulations. Reducing the front chamber size (which seemed to make little difference in Hornresp) improved response considerably, and several exit sizes and shapes were tested, still with less low frequency results compared to the simulation, then I decided to try ducting the horn throat in to a latter part of the horn. After 22 additional tests using a variety of duct lengths and exit positions an acceptable response was finally achieved. The single 12” Domino with extender has about 5 dB less output at 40 Hz output compared to the 7.6 cubic foot WS 2 x Lab 12” 36 Hz Fb bass reflex cabinet it replaces, but 5-10 dB more output in the chest-thumping 70-160 Hz range. With the horn extender averages 120.16 dB from 40-100 Hz at one meter using 41.7 volts input (about 395 watts @4.4 ohms) with distortion averaging only 6.58%. Using a Torpedo SP4000 amp (4000 watts @2 ohm) to power a pair gives around 132 dB output at one meter.

Box size is 45 inches tall, 17 inches wide. 22.5” deep and weighs 110 pounds made of Aruca plywood with a single Eminence Lab 12. Gross volume is 9.96 cubic feet (282.06 liters). The horn extenders tops are 45 x 15 x 1.5, the sides are 43.5 x 22.75 x 1.5, with straps the assembled extender weigh 50 pounds. They occupy 2.114 cubic feet (59.91 liters)

At 24.15 cubic feet (683.94 liters) for a pair with extenders, they take up less truck space than a single LabHorn (45 x 45 x 22.5, 26.37 cubic feet). The larger horns do put out more low frequency, but the Domino DFLH kicks like a mule, and the whole system is pulled by a Mustang. For the type of music I use the small system for, the upper articulation of the Domino is worth the tradeoff of having less low frequency.

Additional construction information is included in post # 2.

Art Welter
 

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For those interested in building the Domino DFLH, more construction information is below:
 

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Ahh ha! Here it is!

Great job Art.

Construction looks like it was time consuming...much more So than a keystone Cab, correct?
Yes, much more difficult.
And I still have no idea why the ducting was required, normally Hornresp is within a few dB or better, but in this build it was not close at all until the ducts were installed.

It took me 28.5 hours of design and testing time, and about 51 hours to build the pair of Dominos with the extenders.
For comparison, I just built a 2 x 10" TH (the Tub Sub) that fits between my outdoor hot tub and the house, that project took about 8 hours of design and testing and 8.75 hours to build, and came out quite close to the Hornresp sims.

For most applications, I'd say a "slim" version of the Keystone design would be preferable, but for the acoustic and lighter pop shows I 'll be using the Dominos on, the flat phase and tons of upper headroom is worth loosing a little LF for.

That said, with a heaping helping of EQ, the Domino sounds good even down in the 30 Hz range, the sealed chamber keeps the cone movement pretty tight judging from the sine wave tests. With "normal" music, the cabinet sounds clean and super punchy with 2000 watt peaks using a 30 Hz 24dB per octave BW HP.

Art
 
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That's pretty impressive that an off the shelf Lab 12 can survive 2000rms with a sealed rear chamber.
I'm feeding my Lab 12 1400rms but the magnet is pretty close to the throat in my 20hz theater horn And I don't really abuse it for hours on end the way a pro audio PA horn is used.
 
i like the car😀
not bad at all for such compact design.
like the extension bit to😎
maybe if you make the extender fit closer to the mouth ,you might gain more low end?
The Mustang is a good tractor, it has about 10,000 miles of towing on it so far.
The extender functions more as a boundary than an actual part of the horn.
It also makes the stack much more stable, tripling the width and adding 15" to the depth. With the gusty winds around here the stack could blow over without the extender attached.
As you can see in the chart in post #1 it is effective down to Fc, but more effective in the upper range.
Making the extender "fit closer to the mouth" would require an additional large piece of plywood at a diagonal, difficult to implement, and would not fit in the trailer. If it made any difference at all, it would be on the order of only a dB or less judging from previous experiments .
 
I was curious about the extender not being flush / sealed up against the mouth...did you test both configurations Art?
The extender is flush with the mouth perimeter and held on with two ratchet straps around the back of the cabinet and one ratchet strap vertically to fix the top and bottom together.

I don't understand your question about "both configurations", what alternate configuration are you thinking of?
 
Art,

you mentioned a lack of interest in this design in another thread, so I came over to look. It's hard to see exactly what the design is from what you posted so far. Maybe a CAD or sketch of the contstruction/cross section would make it clear.

Regards,

_-_-bear
 
Hello everyone, this is my first time here and the info here is absolutely astounding in particular the Domino DFL seems to be exactly what i need. However with the drawings provided I'm still lost. Can someone post or send to a clearer dimensions and instructions.

Thanks in advance
 
The Mustang is a good tractor, it has about 10,000 miles of towing on it so far.
The extender functions more as a boundary than an actual part of the horn.
It also makes the stack much more stable, tripling the width and adding 15" to the depth. With the gusty winds around here the stack could blow over without the extender attached.
As you can see in the chart in post #1 it is effective down to Fc, but more effective in the upper range.
Making the extender "fit closer to the mouth" would require an additional large piece of plywood at a diagonal, difficult to implement, and would not fit in the trailer. If it made any difference at all, it would be on the order of only a dB or less judging from previous experiments .

Ha! My girlfriend gave me so much static when I put a hitch on my car.
As my engineering mind sees it, a car and trailer offers the best of both worlds.
Fun to drive when you need that, good gas mileage, and when you need to buy six sheets of plywood at Home Depot, a trailer can haul as much as a full size SUV!
 
Hello everyone, this is my first time here and the info here is absolutely astounding in particular the Domino DFL seems to be exactly what i need. However with the drawings provided I'm still lost. Can someone post or send to a clearer dimensions and instructions.

Thanks in advance
What dimensions are unclear to you?

I'll answer your questions, but don't expect anyone to convert my drawings to a metric or CAD format.

Art
 
What dimensions are unclear to you?

I'll answer your questions, but don't expect anyone to convert my drawings to a metric or CAD format.

Art

I can't make it out either. I can see where the horn extends from bottom left corner (throat) to the top right corner (mouth), but it's not clear what else is going on at the bottom of the cabinet.

Did you do an impedance response curve for this build? I see you mentioned that it did not match HornResp predictions. I think it would be an interesting exercise to determine why.
 
I can't make it out either. I can see where the horn extends from bottom left corner (throat) to the top right corner (mouth), but it's not clear what else is going on at the bottom of the cabinet.

Did you do an impedance response curve for this build? I see you mentioned that it did not match HornResp predictions. I think it would be an interesting exercise to determine why.
No impedance curves.

I did quite a bit of "exercise" to determine why the "F" ing cabinet did not match HornResp predictions :yell:

The compression chamber is an "L" shape at the bottom of the cabinet.
 

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