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

@islandmandan

Nice, the Herron is a very good phono stage and I still have one around. At one point I thought the different subsonic filtering between phono stages and SUTs could have some impact, but in the end didn’t find any meaningful difference among the combinations tried (4 different phono stages, including Herron with and without SUT). None of the phono stages were even slightly at fault here.

Your post reminded me, I also tried the KAB rumble filter. This was 100% effective at protecting from amp clipping and always kept the woofers rock solid steady -- no more flapping! However I felt it DID have a slightly negative impact on ultimate transparency and dynamics. If left with no other option it’s a good tool, but addressing the issue via proper isolation is superior. I feel my currently isolation grants (roughly) 90% the protection of the KAB, without sonic penalty.

@pindac

Very nice! Thanks for sharing your considerable experience. I feel like a baby in this area, but am happy to at least be crawl-walking now lol. Concrete slab floor is a dream for a future system :)

@gakerty

You Ovation looks fantastic with that Tracer arm, on that Townshend! The Ovation and Innovation Compact are truly the "sweet spot" of the Clearaudio lineup. You can hear the same quality of sound that’s in the Master Innovation. I almost bought a Delos and am glad I didn’t, but it’s at least possible these products could be effective in some systems. I was also kind of shocked how much energy still gets dumped into my suspended wood floor through the Gaia III’s. Superficially these feet are "suspension like", but unfortunately they don't seem to be as effective as a real spring suspension. I bet the difference with a Townshend podium would be huge.

BTW killer setup @mulveling. Those Tannoys probably sound as a good as they look. I thought you were running Rogue monoblocks at one point?  Edit: Thanks, the Tracer arm has been rock solid (so to speak)  and I've run super light, high compliance to heavier mid compliance carts successfully, although my current Stanton has a resonant frequency of 7hz.  Perhaps a bit shy of desired range, but doesn't seem to have a real world effect to my ears.   Anyway, it seems both you are I are somewhat underwhelmed by the Isoacoustics products in our systems, I'm sure others have had better success.  

 

Thanks @gakerty 

Yes, I still have those Rogue Apollo monoblocks -- ran them as my main amp (in non-Dark and later Dark form) in the big loft system for the better part of 10 years. I tried swapping lots of components during the struggles with this smaller system. I must say, the Apollos are so powerful they were NEVER once driven into clipping, even at loud volumes with improper speaker & turntable isolation. However, I realized throwing gobs of power at the problem was not a proper solution. And in the end, I prefer the sweet refined sound of VAC tube amps, albeit at a much higher price tag per Watt. The Apollos are still great amps!

I've been really pleased with the Tannoy Glenair 10's in this small system. I have Canterbury GR in my main system, which I love, and have been surprised how well the much cheaper Glenairs hold up (unfortunately long discontinued). They're easily my 2nd favorite 10" Tannoy after Kensington. 

the Tracer arm has been rock solid (so to speak) and I’ve run super light, high compliance to heavier mid compliance carts successfully, although my current Stanton has a resonant frequency of 7hz. Perhaps a bit shy of desired range, but doesn’t seem to have a real world effect to my ears.

@gakerty I wouldn’t worry a bit about that 7hz resonant frequency. As you know, these Clearaudio tables don’t rumble...at all. And you can get the ring clamp if warps ever cause woofer flapping problems. For a time I though I could (at least partially) address my issues by choosing an arm+cart with the "right" resonant frequency, but the truth is there’s no avoiding the need for proper isolation -- until you solve this, almost ANY resonant frequency will be excited by footfalls and/or LF feedback.

@mulveling It is the continuation of creating experiences with different materials in a Support Structure and the very positive outcomes, that has been the Cornerstone of my other endeavor, which has been to work with electrical interfaces, mainly those that are achievable by a non-EE skilled individual.

When the Source and System are able to deliver in a manner that has a much reduced smearing and the details, micro details and envelope of a note and vocal are manifesting in a way that is quite perceivable as being improved. Changes to interfaces that are effecting the signal path are able to create very noticeable affects on the presentation and quality of the signal. It may be time to swap out or reconfigure some of the Cables used. A change of a Cart' Tag Wire can be quite something. Tube Rolling if some tubes are kept for this can also be revisited, as there is even more on offer from these simplistic exchanges, when the source and speakers are delivering in an improved condition.