Auralex - Subwoofer Isolation Platform

LL21

Well-Known Member
Dec 26, 2010
14,411
2,509
1,448
LLoyd, the custom HAR "cloud" and side panels in my room made the room go away. The openess in the overall feel of the music is wonderful. Steve Hoffman, recording engineer, calls it "the breath of life", that Marshall amp sizzle, or the awareness even when there are no notes played but you feel the room breathe with the presence of the microphones being on.

Here's my room:
http://www.whatsbestforum.com/showthread.php?2717-My-room-s-acoustic-makeover

Stunning! Thanks for that...very, very interesting read! Enjoy the tremendous system (which clearly includes your room!)
 

Nightlord

New Member
Dec 30, 2012
177
1
0
Sweden
I've built my own isolation platforms, basically MDF sand boxes with a caulked MDF lid floating on the sand.

Ha! Someone else who's actually done it - I've just been contemplating the floating lid. (on AVS that idea got me labled with OCD... *LOL*)
 

GaryProtein

VIP/Donor
Jul 25, 2012
2,542
31
385
NY
Thanks. I run the sub 34hz in parallel with 48db rolloff (so as not to 'bleed' into mid-bass of main speakers. Would you be surprised if i told you:
- the mains seemed tighter with Auralex...in the midbass region
- the lower bass fell off a lot
- so i need to turn up the sub volume quite a bit, and i am still not convinced it blends as well as it did before

It appears from your description of the frequency and rolloff slopes that you have a mismatch.

Your set your sub to have a 48dB/octave slope at 34Hz and it is extremely unlikely (actually impossible) that your mains have a matching 48dB/octave rolloff slope. It sounds like you need to use an active crossover so they have matching slopes.

In actuality, you DO need to blend in the sub with your mains via matching frequencies and slopes.

You can use whatever slope and frequency you want. but they must be complementary. For example, your mains can "roll off" at 34Hz and 48 dB/octave, but then your sub must "roll on" at 34Hz at 48 dB/octave, or at 24 dB or 12 dB/octave, etc., but the "roll off" of one must match the "roll on" of the other, and that is why an active crossover is so helpful.
 

LL21

Well-Known Member
Dec 26, 2010
14,411
2,509
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It appears from your description of the frequency and rolloff slopes that you have a mismatch.

Your set your sub to have a 48dB/octave slope at 34Hz and it is extremely unlikely (actually impossible) that your mains have a matching 48dB/octave rolloff slope. It sounds like you need to use an active crossover so they have matching slopes.

In actuality, you DO need to blend in the sub with your mains via matching frequencies and slopes.

You can use whatever slope and frequency you want. but they must be complementary. For example, your mains can "roll off" at 34Hz and 48 dB/octave, but then your sub must "roll on" at 34Hz at 48 dB/octave, or at 24 dB or 12 dB/octave, etc., but the "roll off" of one must match the "roll on" of the other, and that is why an active crossover is so helpful.

Thanks...i am no techie. In my room for whatever reason, by doing this i get within 3db flat from 200hz to below 20hz. not sure why, but there must be something going in the room...at least that's what the Velodyne microphone/meter show when i did the measurements from 20hz - 200hz.
 

kach22i

WBF Founding Member
Apr 21, 2010
1,591
210
1,635
Ann Arbor, Michigan
www.kachadoorian.com
Ha! Someone else who's actually done it - I've just been contemplating the floating lid. (on AVS that idea got me labled with OCD... *LOL*)
FYI: Some Online plans below by another forum member.

http://wardsweb.org/audio/isolation_table.html
fullsm.jpg

I actually ran out of MDF for my top plate and used aluminum foil and pegboard. I think an aluminum plate cut to size would actually be a better material than glass or MDF, if you can afford it.
 

ehoove

New Member
Dec 30, 2012
8
0
1
I use two of the Auralex units under my NHT W2 Subs with good success. I originally used them on bare hardwood floors, and they are presently used on carpet over concrete. I have found both to be a welcome addition with tighter bass and lower extension. The stand up bass on Ron Carter's Etudes, and Stanley Clarke's Journey to Love albums are my measuring sticks. BTW
Regards,
Jim
 

catastrofe

Member
Feb 17, 2012
106
0
16
Saint Louis
Would there be a reason not to use a Gramma under full range floor standers? I would think the low frequency benefits would be similar to use with subwoofers. . .
 

LL21

Well-Known Member
Dec 26, 2010
14,411
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Would there be a reason not to use a Gramma under full range floor standers? I would think the low frequency benefits would be similar to use with subwoofers. . .

i think people do this. in fact, i think if you look at Auralex...they simply call the same product different things depending on whether its for sub or speakers. The sizes are also different as most subs have a bigger footprint.
 

Joe Whip

Well-Known Member
Feb 8, 2014
1,735
557
405
Wayne, PA
I use one of the subdudes from Aurelex under the sub in my HT room and I loved the results. It decoupled the sub from the room and made a noticable improvement in the sound of the room. For the price, well under $100.00 even with shipping, it was cheaper than building one saving a ton of time too.
 

LL21

Well-Known Member
Dec 26, 2010
14,411
2,509
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I use one of the subdudes from Aurelex under the sub in my HT room and I loved the results. It decoupled the sub from the room and made a noticable improvement in the sound of the room. For the price, well under $100.00 even with shipping, it was cheaper than building one saving a ton of time too.

Agree. Tremendous value for money.
 

bonzo75

Member Sponsor
Feb 26, 2014
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London
I used these under my downward firing Summits. They were superb, stopped the sound from going down to the neighbours (due to the the cabinet vibrating on the wooden floor), improved sound quality, and were much much superior to the granite slabs I had initially had.
 

LL21

Well-Known Member
Dec 26, 2010
14,411
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I used these under my downward firing Summits. They were superb, stopped the sound from going down to the neighbours (due to the the cabinet vibrating on the wooden floor), improved sound quality, and were much much superior to the granite slabs I had initially had.

Same under my Velodyne...including the neighbors part! ;)
 

bonzo75

Member Sponsor
Feb 26, 2014
22,442
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London
Yeah London flats suck - below the auralex I put a mat that is used as an anti-vibration mat under washing machines. Looks ugly though
 

dallasjustice

Member Sponsor
Apr 12, 2011
2,067
8
0
Dallas, Texas
but they must be complementary. For example, your mains can "roll off" at 34Hz and 48 dB/octave, but then your sub must "roll on" at 34Hz at 48 dB/octave, or at 24 dB or 12 dB/octave, etc., but the "roll off" of one must match the "roll on" of the other, and that is why an active crossover is so helpful.

In this particular case I agree with you. Generally, I don't agree with you.

It can be very good to use an asymmetric crossover but it's usually the other way around. In my case, I cross my main R/L over at 47hz and 24 db slope. 47hz was chosen to help eliminate the dominant axial room mode which happens to be 47hz (24' long room) using a pair of F113s front and back walls. This works like a charm. The subs are crossed over at 47hz with 12db slope. The reason for the asymmetry is to use subs on opposing walls to also eliminate the backwall null at 54hz; I sit about 6 feet from backwall. The main objective is to get flat FR and phase response around the crossover. If you can do that with an asymmetric crossover and it fixes multipe room issues, then I say: Go for it! :D
 

LL21

Well-Known Member
Dec 26, 2010
14,411
2,509
1,448
It appears from your description of the frequency and rolloff slopes that you have a mismatch.

Your set your sub to have a 48dB/octave slope at 34Hz and it is extremely unlikely (actually impossible) that your mains have a matching 48dB/octave rolloff slope. It sounds like you need to use an active crossover so they have matching slopes.

In actuality, you DO need to blend in the sub with your mains via matching frequencies and slopes.

You can use whatever slope and frequency you want. but they must be complementary. For example, your mains can "roll off" at 34Hz and 48 dB/octave, but then your sub must "roll on" at 34Hz at 48 dB/octave, or at 24 dB or 12 dB/octave, etc., but the "roll off" of one must match the "roll on" of the other, and that is why an active crossover is so helpful.

Thanks...I suppose that is true for anytime you run Mains at full range. But I have found with a speaker running full range and the sub only producing a very subtle bit below 40hz it is helpful without being disruptive.

Obviously an active crossover has its advantages...but I do wonder whether there are potential disadvantages as well...ie, quality of active crossover electronics, extra cables, etc.

I have to imagine a Wilson + Thor is ideal but that is not in the cards, and to get just a touch of bass weight below 40hz, I have not a more satisfactory way of doing that within my budget than this.
 

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