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Turntable Isolation Journey

Nearing the end of my journey to solve footfall & feedback issues in my small-room "home office" system with very bouncy floor and flexible walls. Turntable is the only source here -- and it’s a Clearaudio Innovation Compact with no suspension or special isolation feet. This system always sounded good, but was rendered nearly unusable at higher volumes due to turntable isolation that was inadequate relative to this room’s challenges. The worst artifact was when structure-borne feedback from the speakers would cause amp clipping on bass-heavy tracks. This clipping would manifest as an extremely loud singular POP sound, especially hitting the tweeters. It only occurred during the loudest parts of track with bass-heavy elements, and was so loud it was still significantly above the level of the music -- much louder than a POP you would hear from vinyl surface defects. The POP sound was startling, and clearly very bad for tweeters (fortunately my Tannoys seem to have survived several of these incidents). For a time I thought these POPs were from static electricity discharge, but they were NOT. In my quest I tried many solutions and tweaks over a few months, and I’d like to share a rundown of what worked versus what didn’t.

What Helped (MVP products & tweaks):

  1. Townshend Seismic Isolation platform -- Single biggest difference maker, for combating both footfalls and structure-borne feedback from speakers. Amazingly-well designed and built. Leveling was a snap. Well worth the price! If you spend money on isolation, spend it here. Highly Recommended. I’m now considering more Townshend products for under my speakers and in the big loft rig.
  2. Rack Bracing -- Pushed rack right up against the wall (stud / drywall) with a 2’x2’x2" Auralex foam panel tightly wedged in between the top half of rack & wall. This SIGNIFICANTLY cleaned up rack oscillation from footfalls. I see a LOT of folks with nice turntables atop tower-style audio racks, and they could benefit greatly from this "hack". It is cheap & free; the only downside is you may need to reposition your rack. I learned about this "hack" by a couple comments buried in "turntable isolation" threads searched via google. This really CANNOT be overstated.
  3. HOCKEY PUCKS -- Placed under rack spikes in place of the stock aluminum cups or Herbie’s Giant Gliders. Just let the spikes sink right in! This actually cleaned up the very last bit of energy from footfalls; foot stomps with needle-in-groove are now DEAD QUIET. super cheap and effective! Far superior to most audiophile footer devices. Might also help in rack bracing by tightly constraining the rack between wall & floor (Herbie’s Gliders were too slippery).
  4. Rack positioning -- Get your turntable & rack away from the speakers. If you can move the rack far enough behind your speakers, that might be OK, but most rooms cannot accommodate enough depth for this. Placing the rack several feet down a sidewall worked best in this room. Choosing a structural wall also aids in rack bracing. Make sure you don’t place the rack in a room "node" where bass is amplified. Walk around while music is playing to find a nice quiet-ish spot. I kept my amps by the speakers and ran 5 meter XLR cables from the preamp / rack.

What Underperformed:

  • Critical Mass Sotto Voce rack -- the rack is gorgeous and nicely rigid, but doesn’t have nearly enough mass to combat the bouncy floor in this room. Once braced against a wall, the rigidity of this rack was allowed to shine. However, before the bracing, its performance was poor. I will say I have Critical Mass’s Maxxum rack in my (main) loft system on a more solid floor, and the immense mass & rigidity of that rack was game-changer for that system. I do like CMS products, but they are dearly expensive.
  • Critical Mass Black Platinum filter -- Top shelf of the rack. This actually has a significant positive effect, but is limited to the midrange and treble frequencies. It cannot combat footfalls or low frequency feedback. I still like and use this platform, but at more than twice the cost of a Townshend platform it belongs in this category.
  • SOTA Nova V Turntable -- I thought this table’s suspension would render it impervious to room issues, but it’s not. It helped with footfalls but some structure-borne feedback was still getting through. I suspect the suspension needs a tune-up. Quite frankly I think the OLD suspension (it started life as a 1990s Star III) was better tuned and more stable before it came back as a fully rebuilt Nova V, circa 2018. The new vacuum platter was a huge improvement but the new suspension has been disappointing. The Clearaudio deck also sounds a bit better, so now with the Townshend platform it’s an easy choice. Note that the Townshend also uses springs as its isolation mechanism, but I noticed that the Townshend’s oscillation is far better controlled and damped versus the SOTA. You can SEE and HEAR its performance advantage.
  • ISOAcoustics Gaia III speaker feet -- these seemed to have some small positive benefit, but honestly not a lot. Not worth the money.
  • Lovan Sovereign modular rack (three 10" modules high) -- these are very similar to the VTI racks I see everywhere (which I’m also familiar with). These racks lack rigidity and stability. I would not recommend placing a nice turntable on one of these racks. However, if you do, please brace it against a wall (Auralex foam works great). They’re relatively cheap and look good, so I at least understand their popularity. If you have this rack, at least try hockey pucks under its spikes :)

What Was Worthless (Don’t waste your money like I did):
I’m not going to bother expanding upon these; suffice to say they had no discernible positive effect.

  • ISOAcoustics Orea Indigo feet (under maple board & turntable).
  • Symposium Segue ISO turntable platform
  • Herbie’s Lab Giant Gliders (steel) - Placed under Sotto Voce rack spikes
  • Speaker spikes -- at least they look cool :)

128x128mulveling
prof
3,435 posts
 

@mulveling 

Excellent detailed post and a terrific contribution to the forum!  Thanks!

I also had a long thread on my trying out various solutions in building an isolation base for my Transrotor Fat Bob S turntable.   It's amazing how similar our conclusions were!

First, my sources are all in a separate room from my listening room.  That's already a good thing in terms of reducing any influence from the speakers in the room on the turntable.

But I had very little space and had to use my old Lovan tubular rack because it was narrow enough.  But it's a pretty flimsy rack, not solid at all.  Plus it was on a sprung wood floor and my tall son stomps around like Frankenstein, so footfall was an issue too.

I bought tons of isolation stuff, testing it in all sorts of ways with vibrometer measuring apps, to see which isolated best.

I tried sorbothane products, wall damping, isoacoustics, MDF, constrained layer damped metals etc.  It was finally the Townshend spring-based Iso Pods that did the trick.  They isolated waaay better than anything else.  Put the isoacoustic pucks to shame. 

So I ended up with the turntable on a 2 1/2" thick maple butcher block (wanted that wood look).  Then that sits upon a constrained layer combo of two MDF sheets, which sandwich a layer of steel with wall damp material on each side.  Man, just that MDF/Steel/Wall damp combo is super dead to the rap test!

Then under that I have the Townshend pods.  The pods are really doing most of the isolation work.  I can place my vibration app on the turntable and stomp all around the floor by the turntable and almost nothing registers.

I was impressed enough with the Townshend pods to try the Townshend isolation bars under my speakers (which sit on a shag rug over a sprung wood floor).  In that case, once again, the spring based solution clearly isolated very well.  If I was playing bass heavy tracks I could feel the floor (and sofa) vibrating but with the speakers isolated with the springs, the floor was absent of any vibration.

For me that turned out to be a good and a bad thing.  The speakers did tighten up in the bass etc, but I actually preferred both the tone and the punchiness of the speakers just sitting on the floor.  For my taste the springs isolated a bit too much and I lost some "room feel" in the bass.

So I've been on to experimenting with tons of stuff under my speakers.  I have the Isoacoustic Gaia 2 footers and I preferred them to the Townshend, since there were a 1/2 point - they isolated and tightened things up, but not to the degree of the springs.   It's clear that I want *some* isolation effect but also some engagement with the room.  So I'm trying all sorts of combos.

This is where the hockey pucks come in!  I actually replaced the Gaias on the front of my speakers with speaker spikes in to hockey pucks.  I love the result.  The pucks seem to keep things tight but still pass some level of vibration in to the floor, so the sound is also really punchy.

I've tried a variety of other things too and still experimenting.  Right now I've put a 1 1/4" thick granite bass beneath the speakers too.  That didn't actually tighten up the sound much in of itself, but I like the look and will try to work with it.

Anyway...thanks for sharing your results in such detail!

 

 

 

 

audioguy85's avatar
audioguy85
1,989 posts
 

Luckily I do not have any of these issues...my system is in a basement room, concrete floors and walls. Turntable shelf. Another table, fully suspended thorens, sits atop my equipment credenza, right near the left speaker...no ill effects whatsoever.

noromance's avatar
noromance
9,404 posts
 

Once you go concrete, you can't go back!

Concrete slab floor is a dream for a future system :)

clearthinker's avatar
clearthinker
1,582 posts
 

@noromance    +1 for concrete

Although it's very difficult to implement across a bouncy wood floor.

My system is in the basement standing on very large marble and stone slabs, they standing on the concrete screed in the ground.  I have called this infinite mass loading.  If we can take the mass of Earth to be infinite relative to that of the little stylus riding the little groove.

Those suffering the pain of a suspended floor might consider putting two rolled steel joints in it spanning between two solid walls and build the system supports onto those.  A radical solution but a solid one!  When considering the cost, consider the cost of your system and media and the long-term compromised sound; not to mention the cost of all the isolation systems you want to try.

singingg
111 posts
 

I am blessed with a concrete floor in my house-addition dedicated listening room. I have steel post supports in my stand filled with sand. I removed the spikes and set them on a single hockey puck. I have glued and screwed two piece of masonite under each shelf for great density and vibration absorption.

Audiophile riddle : What is better than a hockey puck?

Answer : two hockey pucks

Yes sir, I discovered this by complete accident. Per this discussion, I have three stacks of two under my Project RPM 10 isolation base, touching the base, not on the footers (experimentation recommended).

A tweak of the tweak : hockey pucks are seldom flat, with one side a little concave and the other a little convex. Flip them until they seat. I use three stacks of two under all my full sized rack components, resting on the chassis, not the feet. This works sometimes even with small components like the iFi microphono 3 (1 set of two). For other small devices and my Furman power conditioners, I have found folded rugs suffice and can be cut to size.

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