Lab 15 design suggestions for HT use?

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FWIW, I looked at this driver in a MLTL awhile back, though it's somewhat larger than 6 ft^3 and tuned lower, but scaling it back a bit and raising tuning to around 22 Hz still seems a viable option and since it's a bit larger than Bjorno's, it's a couple of dBs more efficient down low in a sim.

It's long at 81.75" i.d., so needs at least one fold, but only as wide, deep as required to physically install the driver and vent [~126.83"^2 i.d. to = 6 ft^3 gross or about 5.49 ft^3 net], but being end loaded for both the driver and vent to get max floor boundary gain, this shouldn't be a problem.

The vent would be a 6" i.d. dia. pipe ~8.5" long if laying right on the cab 'floor' or ~12" long if not, so would exit out the side relative to the driver baffle. Might be best to try different lengths in room though since the amount of boundary gain is an unknown.

Sim is minimally damped since the TL action is plenty strong enough to damp the driver, vent, i.e. top, back one side lined with just enough damping to quell any 'hollow' sound and with a typical 80 Hz XO for HT, you can ignore any 'ripple' above this frequency.

GM
 

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Hi,

If you find it necessary: At a small SPL/FR flatness expense: You can tune this ML_TL suggestion even lower than 23 Hz using a Total System Volume less than 5 cu.ft.

If you're interested I let you know the exact amount of required stuffing and the ~damping material density needed, in a few days at most

b:)

This design started to interest me and tb46 drawings show it's not too big to make. So it's cabable of 117dB or more? A minor change possible? I could use about overall of 128dB+, F15 of 20Hz this would nicely be added by room gain. A normal F3 of 30-35Hz TH/TQWP might work too. Is this spl too much asked from Lab 15?
 
This design started to interest me and tb46 drawings show it's not too big to make. So it's cabable of 117dB or more? A minor change possible? I could use about overall of 128dB+, F15 of 20Hz this would nicely be added by room gain. A normal F3 of 30-35Hz TH/TQWP might work too. Is this spl too much asked from Lab 15?

Off the top of my head you would need 4 Lab 15 subs to reach that kind of spl. The question I have is why do you want that spl?
 
Hi duanebrow,

Two of bjorno's MLTL's in parallel into 1pi space (Eg=60), scary stuff :) :

Regards,

Can you post the same with 1 MLTL into 2pi space? Just to compare some designs at Data-Bass

I was also wondering about the s4 s5 duct. It's 280cm^2 and thats same as 6" - 8" diameter port. Also width/height ratio min 9:1 is at close.

Otherwise it's unbelivable how much you can get from 88dB efficient driver! :)
 
Hi Veke76,

See bjorno's Post #7 for the single MLTL into 2pi simulation. The fold I drew up in Post #9 was a general suggestion, the aspect ratio of the duct is 5.64:1 (15.5"/2.75"). I went straight of bjorno's data, and did not enter any end corrections; for any box like this I would suggest a trials box to get a better idea of the stuffing location and density, and so on. If you take this design into AkAbak you can also fiddle with the design some more.

Regards,
 
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4.5 years later I come back to this thread to find I never reported the conclusion. I built the MLTL. It works great for movies. I believe the real world FR matches closely to the model. It is powered by a inuke1000. For normal listening I get one LED (of 4) to light up in action scenes. I did bottom out the sub once while testing. I think it was a dino sound effect that went down to 10hz, well below tuning.
 
Any thoughts or ideas on how to line or stuff this? I am thinking about building one of these and would like to not have to "trial and error" too much! Also, I used the provided Hornresp data and plugged in the Dayton RSS390HO-4 and it looks really good.

I used no stuffing in mine. I think that stuffing effects the midrange mostly. So it is not needed for a sub.
 
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