Auralex Subdude a MUST HAVE!! - Page 4

I decided to make some DIY subwoofer isolators/bass-traps. Total cost for two subwoofers was about $30 for materials, and about 2.5 hours of work. Most of that spent sewing.

Photos.

I have a porcelain tile bonded to concrete floor and my B&W ASW800 can move it.

I've been using the Auralex Gramma for over a week now. To be honest, it did not subjectively lower the vibration levels in my wood-joist floor one bit. My sub (Paradigm PW-2200) has rubber feet and my floor has thick carpet and pad.

I think the bass may be a tad tighter in the room, but that could be $50 out of my wallet talking too.

I played Kodo at high levels and did confirm with my isolators that the floor right next to the subwoofers was not vibrating as it used to. The SVS 16-46PC+ also has little rubber feet on the bottom plate. I don't really think it helps the subwoofer be more efficient, as the energy should be getting absorbed by the foam and fiberglass. Although I guess that does mean energy previously absorbed by the house and possibly coming back to affect the subwoofer is being absorbed too.

I did, however, confirm that bass is tighter. Probably due to faster absorbtion of vertical standing wave energies by the foam and fiberglass, as well as raising the subwoofer driver farther from the floor to help prevent standing waves from forming in the first place. The confirmation comes from my left ear no longer hurting due to boominess when listening to something like Massive Attack's Mezzanine at ~75dB.

My sub (an old Velodyne F1000) already has an inch-thick granite base. Is the main decoupling of the Subdude by virtue of the 'risers'? Because if it's really more the MDF base, I would guess I already have that covered.

Sorry, 'I spent $50 and things sound better immediately' doesn't work for me as evidence. Has anyone taken measurements (e.g., w/Room EQ Wizard, ETF, etc) to see if the Subdue or Gramma are really changing anything substantially at the listening position? (I would guess floor vibration could also be 'measured' by putting a glass or bowl of water on the floor and comparing visible rippling without/with the Auralex device)

There is now the Great Gramma (same as Subdude/Gramma but bigger) for those with large subs.

http://www.sweetwater.com/store/detail/GreatGRAMMA/

Wow, what timing. I just bought 2 regular sub-dudes for my SVS PB12-plus/2 a couple of weeks ago. The new Great Gramma is the perfect size. Oh well.

I just stumbled across this thread. I set up some mo pads, which is another auralex product under a GR Research sub I have been working on. I wondered about their ability to support the weight, and auralex support told me they are the same stuff that is used for the gramma and sub-dude, and as long as the weight is evenly distributed, everything is cool. My sub weighs 140 lbs. If you are looking to do a custom job, you could cut some MDF to the proper size and put mopads under it. Here is a picture of the sub (in progress) with mopads under it.

This thread reminds me of the recommendation I remember reading back in some old Stereophile, which was to use four tennis balls under the feet of the sub to act as a decoupling device.

Has anyone tried this? If so, how does it compare to the results of the Subdude? Anyone with a Subdude want to try an A/B test?

Scott

I posted in another thread about my problem with my Outlaw LFM-1 making just muffled sounds and it turned out it had sunk almost completely into my carpet. Now that I have the the Subdude (took about a week to get from Sweetwater) it sounds like it is supposed to. I still get some rattling due to construction, but I can adjust for that. It also helps keep a little of the sub sound from going through the floor (theater is on the second floor).

If you mean, me, yes, that's exactly what I'd like to see. Why don't you post them here instead, so everyone else can see them too?


96 posts of anecdotal evidence doesn't make the quality of the evidence better. Fugghedabout science, I guess. And btw, up yours.

you have a PM my friend

James

I believe the subdude will not only isolate the sub from the floor (I did stand next to the sub after installing my isolators to verify less floor vibration) but that placing "trap" material under the isolator will reduce the decay time of standing waves.

I haven't done measurements on my isolators, but Secrets did some measurements off a different subwoofer isolator product (taller and more expensive than the subdude) that didn't have much effect on the SPL but did have some effect on the decay time.

The 'trap' area under the subdude/gamma is so small I find it hard to believe it would have much effect on standing waves. But a waterfall plot would tell the story, for better or worse.
Perhaps I will suggest to Ethan Winer that he test one of these devices.

Spikes and the Subdude are opposites.

Spikes couple the sub to the floor. The Subdude (and other things like it) decouple the sub and floor. It damps the vibrations what would excite resonances in the floor and adjoining structure.

Not entirely true. Concrete does vibrate sympathetically, but has different resonant characteristics from e.g. floor-over-joist. It has more mass and is stiffer, and may not be free-standing, so the resonance amplitude won't be as large. But concrete transfers energy much better than wood. Using a Subdude should significantly improve sound isolation on concrete floors. Conversely, spikes will make it worse.

There's no controversy about damping sympathetic vibrations in the structure. My floor vibrated so much that after several minutes of bass-heavy scenes our feet would start to get numb. After the Subdudes, most of the vibration was gone.

One thing I did not expect, though, was the "tightening up" of the bass. I heard it and it's been widely reported, but I'd definitely like to get a handle on what's happening, if anything. This has been reported in rooms where structural resonance (supposedly) wasn't a problem. Think we could get Ethan to do it?

I have my SVS 20-39 PC+ on a bottom floor, carpeted under concrete. For whatever reason, I get huge low frequency reenforcement. I've played with positioning, and some spots are better, but no spot is ideal. I can get up to +15 db boosts from 20-30 hz range. I have the SMS-1 eq and it definetl does what it needs to. I'm just wondering if in my situation this device would help my situation at all or not because it not being a hardwood floor.

While, some boost is nice, this is over the top and silly and just doesn't sound right. Again, the sms-1 definetly works, but I would like to get it naturally better first, then electronically for whatever remains.

Well, I wonder if reducing vibrations in large room objects, including walls and floors, would perhaps 'tighten up' the sound significantly all by itself...requiring no 'trapping' role for the space beneath the device.

I'm definitely considering it. I'm moving to NYC in a month, to an apartment, and would wait until then to order it. I'd also consider buying one and loaning it to Ethan or Terry (Montlick) for measurement, since they're much more adept at the techniques than I am.

But in the meantime, if anyone has such data to share, I'd like to see it.

I believe this will work in theory, but only if you use audiophile grade Tennis balls.

Yeah. I think I already apologized for that blanket statement.

As for the Subdude on a concrete floor, I was unable to hear/feel any difference with or without it. It is possible that my neighbors would experience a difference but I don't ask.

On a wood/joist floor, however, the differences are palpable.

Kal

So I just ordered two used grammas off audiogon last week that should be here this week. One for my PC-Ultra and one for my Cinenova 5. Eventually I plan on using either both for a DIY i'm going to build someday or maybe some other way. I have a door that rattles at certain frequencies and wall mounted DVD holders that rattle at certain frequencies also. Anxious to see if this helps. Too lazy to fix it otherwise.

Oh, I find it hard to believe that the small space underneath the platform has any function as a trap. Doesn't it have to be some fraction (e.g. 1/4) of the wavelength of the influenced frequency? A 3' platform would have no effect on anything below about 115 Hz.

As I said, the 'tightening' effect has been reported in spaces where structural resonance wasn't an issue, e.g. all-concrete rooms. I rather suspect that it has something to do with the support of the subwoofer case, affecting the way the case moves in relation to the cone. There should, then, be a difference between down- and side-firing designs. But I haven't noticed any pattern in the reports. (Mine are down-firing.)

Well after reading all the good info about the Subdude, I went down to Guitar Center and picked up a Gramma, instead of having to order a Subdude. I first went to my Dads house to see how it would work with his B&W sub. I have always felt it was boomy. Along with my 63 year old mother, that can't stand boom, we put on U-571 and went straight for one of the depth charge scenes. First we played without the Gramma, and not only hers but my ears started to hurt. Then replayed it with the Gramma. Still loud, but both of us felt that it was much clearer and it did not hurt either one of our ears. Very subtle but noticeable. I plan on buying one for my father for his birthday. I have a SVS PB12-ISD, and just placed it under it, but have not had a chance to test it out. Kinda looks goofy though, since the sub overlaps it. I am thinking I might not notice as much difference with my sub, because I have never felt it was a boomy sub, unlike my dads.

I have thick carpet. Will the Subdude make much difference for me?