no i don't mind a little sawdust on my lambo mrgsr gives me a reason to take it for a spin then handwash it again.. and Neo I think i am going to hunt down a dual 4 ohm and run this beast on 1 channel of the amp. wouldn't mind actually buying 2 and just go 2 boxes of this setup should be plenty I think personally this 1 box sounds louder than the 2 3015lf's .
If you want to run L7 boxes only, then you can stay with D2's, wire both boxes in series and bridge the amp @ 8ohms. The amp will be very happy with the easy load and you will have plenty of power. Later on you can double that and have your ~140dB1Pi aggregate SPL, all on one amp. Muhahah!!!
In my experience, 'bench racing' SPL sims at these frequencies, especially in 2pi space has little/no meaning in a typical HIFI/HT room since they aren't acoustically big enough plus every movie ULF measurement I've seen is well below what this TH is likely capable of in-room; so, other than a few special effects recordings, what music, movies are available that's likely going to 'spank' the driver when played at 85 dB avg./115 dB peaks/listening position assuming the 1 pi sim is accurate enough for real world corner loading?
GM
whats the setup of the room? any space for distributed bass? one in each corner of the room would help combat the nodes
Are these the correct parameters? I have the Kicker 08S15L74. I used
S1 = 20.5" x 8.75"
S2 = 20.5" x 8 9/16"
S3 = 20.5" x 8 7/32"
S4 = 20.5" x 8 1/32"
S5 = 20.5" x 7.5"
Length = 8" + 46" + 46" + 8" = 108"
Hi BP1Fanatic,
I checked your parameters and found they are quite in order but I'm sorry(and not surprised) to say they don't fit your driver,the L74, or the L7, that is if the T/S are correct...The suggestions must peak severely, like boom-boxes.
The terminus is too large for a T-QWP and the internal length is too short(tuning is very high).
This design is more of a misaligned QWP and must be stuffed at least to the half-ways with maximum rec. amount(and density) of damping material in order to suppress the severe peaking occurring at above ~35 Hz for the L7 driver.
The L74 peak is lower (still too large) when at ~30 Hz.
The peaking at 90-100Hz is not a problem and would in reality be much less than HR predicts... nearly gone if a 24 dB or higher order LPF is used at ~80 Hz or below...
I will be back later with suggestions both for the L7 and L74 and with 'as is' simulations to back up my statements here-above.
Submitting a picture showing the HR result if S4 is ~992 cm^2 ,not as the built S4 that is more than 23% larger.
b
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compared with the driver in a T-TQWT. 
it would excite all the even order modes.
http://www.harman.com/EN-US/OurComp...ents/White Papers/LoudspeakersandRoomsPt3.pdf
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Hi NEO Dan,
I looked here:
Kicker Product Manuals | KICKER
+ used parameters from post# 16 and 17 here-above.
b
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S4 is ~992Submitting a picture showing the HR result if S4 is ~992 cm^2 ,not as the built S4 that is more than 23% larger.
b
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Hi Dan,
Thank you... Your design is IMO a ...perfect... T-TQWT design using the Kicker_08-15inch-L7D2 driver, not the one I previously simulated here-above(discard that picture!) using wrong T/S.
Here is a MJK simulation that show (your design) the benefit of using (mandatory) damping.
My recommendation is using a fiber density somewhere between min. 0.35 to max. 0.5 kg/m^3 in a T-TQWT or a T-QWP if a driver of this type is used:
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Hi Dan,
I guess it normally takes less than a minute..up to 10 minutes at most for the more comprehensive models to be completed.
b
I believe so, bjorno's model has a stuffing density of ~.5lbs³' if I am reading it correctly. I think the red traces represent the improvement of the stuffing over the un-stuffed(grey) trace. Although some efficiency is lost when stuffed the transformation from resonant to well damped alignment would be of great interest to those who listen critically to their systems. In this case it appears ~6dB is cut from the low end of the response. You may want to try a few of the cheap pillows from walmart, they used to have some for $2.50 called deep pockets they had ~21oz of polyfill in them that could be unrolled into a long bat. You could unroll it and re-roll it into a long but thin shape that could be installed in your box one in each of the four compartments should be "perfect"
. I think I would use a plastic garbage bag as a liner so you could work the stuffing into place to save yourself lots of grief from snagging on the rough wood. But once you have it in place remove the bag. Thanks bjorno, now I am very curious to model more of my design catalog with the MJK worksheets. I am now reminded why I don't already have the MJK worksheets - MathCAD is
$$$/I have
. What version do you use or recommend I use?If targeting SQ too, it's IMO necessary for any type of quarter-wave designs to partly damp the internal airways besides true horns,waveguides of course.
For this design I think that 5 lbs/ft^3 is a maximum density to be used.
Good result is achieved if evenly stuffing the first of suggested sections using normal advertised damping materials starting counting from the largest CSA of the T-TQWT.See the picture:
If choosing mineral wools like 'Rock-Wool' or similar denser materials:
Another stuffing scheme should be used where the applied material always should leave a free airway path through the entire enclosure, never being allowed to physically block the volume more than 40%.
First:Start stuff the immediate volume behind/close to the driver = ~a ¼ of the internal length + evaluate by a listening test and if found not enough continue to fill but not more than half of the total airway length.
I'm still using all the different MJK worksheets he ever have published from the very first ones , MJK recommends using versions from MathCAD version 8.
Sorry for my bad english..b
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