If you had 8-10 15s, how would you....

[eRiCdWoNg]

.... make use of this driver so that low subsonic bass would be the priority. I have a Crown Macro-Tech 5000vz amp to power all of these woofers (probably will use 8 of them). Sound quality is 2nd place, but low subsonic bass takes priority.

Would you- do a large sealed enclosure for each woofer with active EQ? OR a ported design tuned very low? I have access to bass EQ as well. I also will use a dbx 120 subharmonic synth as well as DVD's. I want this thing to send shockwaves thru the house! I thought about horns etc but I think this would be the easiest.


They will either be this driver with these specs:

Overall Frequency Response 18-150 Hz
Nominal Impedance 4 ohms
Minimum Impedance 3.25 ohms
Power Handling (continuous) 400 w
Power Handling (peak) 800 w
Efficiency 90 dB
Voice Coil Diameter: Driver 2" (5.08cm)
Magnet Weight 63.40 oz.

--------------------------------------------------------------------------------

Driver Mounting Depth
Top Mount 7-3/8" (18.73cm)
Bottom Mount 7-15/16" (20.16cm)
Cut-out
Driver Cut-out Diameter 13-15/16" (35.40cm)

--------------------------------------------------------------------------------

Theile/Small Parameters
Recommended Enclosure Sealed / Ported / Bandpass
Resonant Frequency 24 Hz
Qms 6.07
Qes 0.55
Qts 0.51
Vas 6.595 cu.ft./186.75L
Sd 126.22 sq.in. / 814.3 sq.cm.
Xmax (linear) .37 in. / 9.5 mm
Xmax (mechanical) .79 in. / 20 mm
Le 2.20 mH

--------------------------------------------------------------------------------

Other
Product Weight 22.50 lbs.


Or this driver: which is similar but SVC:

Overall Frequency Response 18Hz-150Hz
Nominal Impedance 4 ohms
Minimum Impedance 3.5 ohms
Power Handling (continuous) 400 w
Power Handling (peak) 800 w
Efficiency 90 dB
Voice Coil Diameter: Driver 2" (5.08cm)
Magnet Weight 63.40 oz.

--------------------------------------------------------------------------------

Driver Mounting Depth
Top Mount 7-3/8" (18.73cm)
Bottom Mount 7-15/16" (20.16cm)
Cut-out
Driver Cut-out Diameter 13-7/8" (35.24cm)

--------------------------------------------------------------------------------

Theile/Small Parameters
Recommended Enclosure Sealed / Ported / Bandpass
Resonant Frequency 24 Hz
Qms 10.21
Qes .49
Qts .47
Vas 6.595 cu.ft/186.75 L
Bl 15.8 Tesla Meters
Sd 126.22 sq.in. / 814.3 sq.cm.
Xmax (linear) .37 in. / 9.5 mm
Xmax (mechanical) .79 in. / 20 mm
Le 3.01 mH

--------------------------------------------------------------------------------

Other
Product Weight 22.50 lbs.

[454Casull]

In-home use? I would suggest an IB.

http://www.linkwitzlab.com/woofer.htm

I would suggest building a W-frame to house the woofers (expand it so that it can hold all 10 or something) - that way the non-linear distortion is reduced and the net "recoil" forces are minimized - and then build the W-frame into the wall.

[SY]

I'd be very tempted to try an extended transmission line in the spirit of the Nelson Pass design (El-Pipo).

[wingman]

IB ! !

What model are the woofers ?

[GM]

Why two threads for the same driver? Would this sub be suitable for dipole or horn loading or both?

GM

[Paul W]

IB...with adequate linear displacement you don't have to sacrifice SQ to achieve house shaking subsonic bass. With EQ you can do whatever you like...I use only hi-cut with low-Q drivers for extremely natural but quite extended bass.

You can break windows if you want, but I bet you'll choose sanity instead. It is very easy to love truly clean bass.

Twin IB subs

[TheoM]

Going ported that low (I assume you want to go 20 hz and below) is both problematic and risky. For the first driver I calculated a ported box optimal at 28 cubic feet (two drivers per box) and tuned to 18 hz. That would shake the place - assuming you had any house left to put it in.

Sealed will save you a lot of space and give you driver control below resonance, which you want - trust me. You can use your eq to fix the slope - but even sealed its f6 is like 30, which might be fine. This all assumes I keyed in the st parameters right.

With that much cone area (8x15") and power you will shake the house. btw my design assumption was you would use two drivers per box. Two drivers in a sealed box will save you making boxes (you still need 4, I guess). It will sound tighter and higher fi than a ported box or bandpass - either of which will be more effecient - but you don't want coloration when its that loud - I hope. Anyway, that's what I'd do. If you want to get exotic check out the post refering to the guy who made his entire basement into a 30 foot horn. I think he used 8 15's. search for "whole basement". The nice thing is with the sealed design you can push it down as low as your speakers will go without too much fear of blowing them.

With bass that loud in a house you have no chance of hi fi really since every wall and board will be resonating and every wall reflecting... standing waves everywhere etc.

[eRiCdWoNg]

Heres my dillemma- an IB setup or one of those in the basement horns is probably out of the question. This is for my parent's house. Although I'm moving out soon theres no way this will fly in a townhouse/apartment, so thats why I'm doing it in there house where we are here in the middle of nowhere. They know I have a passion for audio, and dont mind large speakers sitting around (magneplanar system in family room and full pro audio system in living room, not to mention all my past projects.....), however I do think they're going to draw the line at cutting holes in the wall/ceiling for 10 15" woofers haha. this does give me an idea though- the basement is large but unfinished and is all concrete. That means minimal things vibrating and maximum bass reinforcement instead of the walls flexing. I can probably build a "wall" for an IB setup, not to mention with 5000 watts I bet bass will still travel outside of the house.

A wall full of woofers with an ourboard box is a different matter though. I already had to have a 30 amp circuit (here in the USA, its usually 15-20 amps for a residence) wired into the room to be able to power the Crown amp to its full potential.

In the meantime if i were to do this in the family room, I'm leaning towards the sealed box with EQ. I'll probably have to use the PA system with this setup since I've been able to rupture my Magnepan's ribbon tweeters with just 2 18" pro audio subs in the past.

I cant wait to get my own *house* where I can do something insane. And the poor woman who winds up marrying me will have to be tolerate of my speakers!

[johninCR]

I'd go with the first driver due to the 30% lower Le. Then build 2 W baffles with 4 drivers each in push/pull alignment to lower distortion, lower the effective Fs, and reduce box vibration. Build them with sufficient back chamber volumes so you could try them as dipoles or close the back and go sealed for more output and lower extension.

[eRiCdWoNg]

Hmmm, interesting I never thought about the W frame design- that may be ideal actually, since I can do both dipole (for my Magnepan system) and then if I attach the rear panel, it essentially becomes a sealed. Of course its gonna look like a mini phone booth. I thought about doing a seperate H frame dipole but since this was brought up, I may do the W frame. And then the "push pull" alignment will help to cancel distortion too. Excellent.

John- do you mean to build 2 seperate stacks, so the woofers are 2 high x 2 wide? Then put the stacks on the outsides of my main speakers?

Cause I was considering making one stack, thats 4 woofers highx 2 wide. Is it acceptable to put a stack (i think thats what "extend" the W frame meant?) the woofers, allow for the bracing but have them share the same air space, or should each 'stack' of woofers have its own 'shelf'?

Should I use 15s or 12s? Since I sorta care about the quality of the sound, I wonder if 12s offer better transient response? But I know 15s can move more air, go lower, handle more power.....and transients in the dipole setup might not be an issue.

Is there another site that offers more info on the W frame (like calculations, etc) instead of the linkwitz site which sorta just gives a set of dimensions and thats all?