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Auralex Subdude Subwoofer Floor Isolator - tiny amateur review with measurements

anphex

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The Specs and manufacturers description

Description​


The Auralex SubDude-II™ Subwoofer Isolation Pad is a lower profile version of our classic SubDude™, and is perfect for small subwoofers in home theaters and hi-fi systems. This patented, isolation platform features a stylish velour covering over an inert structural layer that floats on a cushion of acclaimed Auralex Platfoam™. This carefully engineered solution allows the true sound of your sub to come through by negating resonance artifacts.
Based on the same Auralex technology that famous recording artists use on-stage and in the studio, this carefully chosen combination of specialized materials instantly diminishes structural vibrations, resulting in cleaner and tighter bass, reduced coloration and a more accurate low-frequency response. The SubDude-II™ is an incredibly effective isolation platform that instantly improves your subwoofer’s performance.
subdude2description.png

Benefits:
  • Dramatically reduces structural vibrations through walls, floors & ceilings
  • Preserves the accuracy of the original audio track
  • Tightens bass and increases low-end clarity
  • Great for home theater & Hi-Fi speakers
Technical Details
  • 15” x 15” x 1.75” Isolation platform
  • Need Bigger? SubDude-HT™: 18” x 22” x 1.75”
  • Supports Subwoofers up to 200 lbs.


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The review

Test Environment:

  • Sonarworks Measurement Microphone with cal file
  • Steinberg UR22 Mk2 Interface
  • Windows 11 PC + REW
  • KEF KC92 Subwoofer
  • Auralex Subdude
Procedure:
I measured the subwoofer in the same position twice: once with the Subdude and once without. For both setups, I conducted 8 sweeps using a acoustic timing reference, followed by Cross Correlate Align, and then Vector Average to extract the pure measurement signal.


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Result:
The Subdude appears to offer a MINIMAL (no significant) advantage in my home setup:
  • ~120 Hz: 2dB reduction (possibly filtering resonance from the wooden floor)
  • other than that, the benefits not noticable

Considerations:
  • Maybe the Subdude is not entirely useless and might cause more improvement the "worse" the paired subwoofer is. I think the KEF KC92 with Force Cancelling already minimizes resonances in the enclosure effectively,
  • Simpler, less rigid subwoofers with configurations like 1x Front- or Downfiring might experience noticeable improvements above 100 Hz with the Subdude, maybe even below that.
  • Physically, achieving improvements below 100 Hz with a thin foam layer and a fabric-covered wooden board is limited generally speaking.
  • Self-Test: You can easily check if your subwoofer is strongly resonating by touching it during a normal music track to see if the enclosure vibrates. Good subs should never do this.

Investment Consideration:
  • €70 spent on the Subdude might be better invested in a empirically superior subwoofer.
  • The Subdude is not a magic solution and primarily serves as a stopgap with some placebo effect.

My Conclusion:
Since the improvement in sound quality is too marginal for my setup, I will send it back. Though I will keeping looking for a solution that makes my floor stop vibrating.
 
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I tried the same type of product from primeacoustic under my floor standing loudspeakers and didn’t find any benefit.
 
My experience with the original SubDude was dependent more on the floor construction than on the sub or its placement.
In my erstwhile weekend place with its wooden floorboards over wooden beams, it cut down on floor vibrations which were detectable via touch and, presumably, might be audible.
In my apartment with it reinforced concrete/steel construction, it seemed to make no difference at all.
 
I think at the end of the day it comes down to the thickness of the acoustic foam below the subwoofer. I will order 2x 5cm layers of basotect and measure again, then post in this thread. I reckon this topic is interesting for people with wooden or other freely vibrating floors.
 
I think at the end of the day it comes down to the thickness of the acoustic foam below the subwoofer. I will order 2x 5cm layers of basotect and measure again, then post in this thread. I reckon this topic is interesting for people with wooden or other freely vibrating floors.
Doesn't hurt to try, but I would expect that it's a waste of time and money. I would expect that the thickness in this case matters to a very limited degree: If you put 5 mm of foam below the sub and due to its sheer weight the stuff is compressed to death and the sub is technically touching the floor again - yes, that's not enough thickness. But other than that, as long as there is no hard chassis to floor or wall contact, there's not going to be much if anything to gain by adding more foam or padding.

Unless your sub is set right on a solid surface and/or fastened to the floor or wall, the vast majority of the energy transfer from your sub to the critical surfaces will happen via the air. The relevant Eigenfrequencies of your room and floor will still be excited by the acoustic energy injected into the room by playing music, even if it's well "decoupled". Those Eigenfrequencies can only be influenced by changing the room geometry, building materials, or adding a fuck ton of very thick material of a specific, tuned density on a lot of surface area. For most residential properties, that's not a viable option.

I think these decoupling pads are a viable solution if your sub is sitting directly on a hard wood, tiled or concrete floor and is thereby mechanically "coupled" to the building. Otherwise, they won't do much if anything. Your original measurement may even be run to run variation. I wouldn't count on that small difference around 120 Hz being "true". Maybe you unintentionally moved the sub 2 cm in one direction when installing/removing the SubDude, maybe someone bumped the microphone stand without noticing or there was an external sound source (e.g. truck driving by) in one measurement and not the other. Who knows.

That being said: I applaud the effort and the measurement-based testing approach. It's nice to see actual data.
 
Doesn't hurt to try, but I would expect that it's a waste of time and money. I would expect that the thickness in this case matters to a very limited degree: If you put 5 mm of foam below the sub and due to its sheer weight the stuff is compressed to death and the sub is technically touching the floor again - yes, that's not enough thickness. But other than that, as long as there is no hard chassis to floor or wall contact, there's not going to be much if anything to gain by adding more foam or padding.

Unless your sub is set right on a solid surface and/or fastened to the floor or wall, the vast majority of the energy transfer from your sub to the critical surfaces will happen via the air. The relevant Eigenfrequencies of your room and floor will still be excited by the acoustic energy injected into the room by playing music, even if it's well "decoupled". Those Eigenfrequencies can only be influenced by changing the room geometry, building materials, or adding a fuck ton of very thick material of a specific, tuned density on a lot of surface area. For most residential properties, that's not a viable option.

I think these decoupling pads are a viable solution if your sub is sitting directly on a hard wood, tiled or concrete floor and is thereby mechanically "coupled" to the building. Otherwise, they won't do much if anything. Your original measurement may even be run to run variation. I wouldn't count on that small difference around 120 Hz being "true". Maybe you unintentionally moved the sub 2 cm in one direction when installing/removing the SubDude, maybe someone bumped the microphone stand without noticing or there was an external sound source (e.g. truck driving by) in one measurement and not the other. Who knows.

That being said: I applaud the effort and the measurement-based testing approach. It's nice to see actual data.
I did 8 measurements per scenario and cleanly averaged them, so run to run variation should be excluded. I took utmost care to place the sub exactly on the same spot. If it was in a different spot, the whole measurement would have slightly different I guess. But of course this is no exclusion and I might have moved it a bit in comparison to the first measurement. But even then 1-2cm shouldn't make a difference at exactly 120 Hz in an amount of 2 dB. For that the wavelenght is just too long for a misplacement to have such a large impact in such a tiny distance.

Note that I will buy 2x5 centimeters, so total of 10cm isolation foam. Not just 5mm. :)
 
I did 8 measurements per scenario and cleanly averaged them, so run to run variation should be excluded. I took utmost care to place the sub exactly on the same spot. If it was in a different spot, the whole measurement would have slightly different I guess. But of course this is no exclusion and I might have moved it a bit in comparison to the first measurement. But even then 1-2cm shouldn't make a difference at exactly 120 Hz in an amount of 2 dB. For that the wavelenght is just too long for a misplacement to have such a large impact in such a tiny distance.

Note that I will buy 2x5 centimeters, so total of 10cm isolation foam. Not just 5mm. :)
OK, thanks. That makes it much more likely that the (small) difference is real.

The 5 mm were slightly exaggerated and meant to exemplifiy a boundary condition where thickness will become relevant. Looking forward to your next results, although I fear we might both be disappointed ;)
 
Nice, thanks for the review and sense-check. Appreciated :)
 
You can do that a lot cheaper and better with 2 stone tiles and a piece of rubber sheet of about 3-5cm thickness between it. But only if your floor is not solid, it will make a lot of difference. With my old stone floor (where the underfloor is direct on soil) it does not do a lot. The floor is already very strong and damping. On suspended wooden floors it may help altough.

The same trick also works very well to damp turntables so the needle don't dance on the bass in high power systems. It's an old dj soundsystem trick from the time the dj setup was 2 technics turntables and a mixer. We (i worked for a p.a. rental companies about 25-20 years ago) sometimes put subs under the dj stage and that trick damped all the bass feedback from the needles out of the way.
 
I would recommend elevating the subwoofer on 1.75" of MDF for the "before" measurement just to be sure the height is not causing those tiny differences.

My subjective experience is that isolation platforms never improve good subwoofers, and actually worsen the tactile feel that many home theatre setups with wood floors experience.
 
But why choose to eliminate vibrations through the floor when they aid our perception of bass IMHO?

That’s why I kept some level of contact with the speakers to my wood floors.

I found when I fully decoupled the speakers via springs, I lost some connection with the sound. And it wasn’t contained only to the bass - my perception was that the whole Sonic presentation felt more solid and palpable when there was some coupling of the speaker to the floor (and I could feel vibrations).
 
But why choose to eliminate vibrations through the floor when they aid our perception of bass IMHO?
I do not know about you, but if the increased booming and rattling of floor, walls, windows and furniture adds positively to the sound I would question my setup very much. That is not the kind of sonic characteristics I like to add to the sound at all.
 
I do not know about you, but if the increased booming and rattling of floor, walls, windows and furniture adds positively to the sound I would question my setup very much. That is not the kind of sonic characteristics I like to add to the sound at all.
I have rarely had that as a problem and, when I have, I have been able to quell the rattles.

I listen to a lot of organ music. Having the bass notes, the very low bass notes, come through the chair is a delight. I heard of a recording studio designer who was asked to work on a studio whose productions were bass heavy. The floor was concrete. A framed floor was added on top, and the problem vanished.
 
My experience with the original SubDude was dependent more on the floor construction than on the sub or its placement.
In my erstwhile weekend place with its wooden floorboards over wooden beams, it cut down on floor vibrations which were detectable via touch and, presumably, might be audible.
In my apartment with it reinforced concrete/steel construction, it seemed to make no difference at all.
ime. you are correct. this will matter most with suspended wood floor.
 
ime. you are correct. this will matter most with suspended wood floor.
Well that's exactly my floor. Whole house is made of planks and drywalls. Pretty rare in Berlin though.
Prefabricated wooden house from Poland.
 
if i might. if your floor is concrete, you shouldn't need a subdude or the like.
if you have suspended wood floors like mine, it will make some difference but not much. there isnt enough mass to offset any vibration.
now, im not an engineer like some of my fellows here, but im just smart enough to think id need something heavy to counter vibration. and i can read and even comprehend good. i did a lot of research on decoupling. a lot. i slept in whatever that hotel was...
in my journey, i used a lot of different things. here's my layman's results.
i started with rubber pads, rubber/cork, rubber/sorbothane (omg, did that suck ass), wood plinths. rubber mats. pavers. and combinations of all those. it came down to a combination of concrete pavers and mat cut from horsestall mat(suuuper dense).[i had some left over after making a deadlift platform.]
the final(haha)solution, my towers are naked-footed on a paver with a horsestall mat under it, on carpeted wood floor. the subs sit on isoacoustics sub stands on a paver. lemme tell you, this has significantly reduced floor and wall resonance. id rate it 8/10. really.
no, i dont have graphs. im not that technically advanced. but i can hear purty damn good. i didnt need a graph when the effect was quite easily noticeable.
before reaching this solution, i could hear/feel my bass on the first floor. i could hear thumping loudly in the back of my apt.
now, you have to be in front of my door and my gear on 9, to even hear it. im sure my neighbors get some but it's low.
i went into the apt below mine when it was open for cleaning. i had to be up to 65-70 before the thump could be heard. and low at that. at 75db, it was nearing intrusive levels. im usually listening at about 50-60db.
side comment: the rubber/sorbothane pads sucked ass. literally. it was muddy and dull low, and everything else seemed off. it was immediately noticeable. i put them in and out three times to be sure. light switch noticeable.
everything else had mostly positive results.
ive seen sand trays. thats my next project. to see if either is better.
 
I did another highly precise measurement comparing raw floow and using 10cm of basotect.

No significant difference. Maybe I should try out concrete terrace plates, just out of curiousity.
 
A dual opposing subwoofer will not vibrate much to begin with, but something like this could help reduce audible vibrations from other things in the room.

And some subwoofers have a tendency to move, so could perhaps help with that. I remember the Sunfire True Subwoofer, from, I don't know, late 90s? It literally walked around on the floor if you played loud enough. :)
 
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