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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
mijostyn's avatar
mijostyn
8,570 posts
 

It all counts, everything. Isolating turntables from the environment is very difficult. You are trying to keep it from doing what it was designed to do and that is measure vibration. Concrete slabs are a great help with stability. Stability and isolation are two different issues. Foot fall problems are a stability issue. Feedback problems are an isolation issue. Some solutions affect both issues but are very interdependent. Concrete slabs are worthless if you have a wobbly rack. Your 10 year old should be able to run into the whatever the turntable is sitting on without making the turntable skip. That is the ultimate stability. This in no way guarantees good isolation. Concrete slabs do not isolate you from environmental rumble. Those of you with concrete slabs and subwoofers, put your stylus down on a stationary record and turn the volume all the way up. If you have a high pass filter turn it off. Look at your subwoofer bounce. Ideally they should not move at all. Turn on the AC and watch what happens. Check out the washing machine and the dishwasher. Only isolation platforms on ultimately stable platforms, tuned to a very low frequency will extinguish this. 1 to 3 Hz is the range most quote. The MinusK is so good at it because it is tuned in both the horizontal and vertical directions but put it on an unstable platform and it is a nightmare. Same goes for any suspension turntable  although some are better at handling unstable platforms than others. 

@mulveling, I am not sure why you had so much trouble with the Sota. Did yours have the magnetic thrust bearing? Eclipse drive? I did have an issue with feedback at a very low frequency with the Cosmos. It turned out to be the three chambers acting like a Helmholtz resonator. Putting a skirt around the plinth closing off the cavity below the turntable fixed that problem. Otherwise,  I have been totally pleased with the table. I also have an ultimately stable cabinet on a concrete slab. The subwoofers remain fixed with the above test regardless of anything else going on including the 10 year old. As for sound quality, it has none. Turntables are not supposed to sound. Any differences are usually easily proven to be from tonearms, cartridges and adjustment. 

sokogear
1,095 posts
 

+1 Townshend seismic platform. Improved the sound of my Rega P8 as their sales guy said, startlingly. I have a suspended hard wood floor over a crawl space.

Interestingly though, the platform actually created footfall problems that previously did not exist. When I spoke to Max Townshend about this (RIP) he was not surprised because of the frequency of his pods and footsteps interacting. He said the solution was to either live with inferior sound without his platform, or put the platform and table on a wall mounted shelf, which thankfully fit nicely and got the approval from the boss for it since it looks like it is almost sitting on top of the credenza where my other equipment sits (on top of Sympoium roller blocks). I guess I was solving multiple problems like @mijostyn  was talking about.

I am sure the combo of the Townshend and the wall shelf make my TT sound like a far more expensive one and the vibration detectable versus the amp on the credenza was reduced like 99.9%.

ghdprentice
6,965 posts
 

I had a Silent Running Audio Ohio Class isolation platform built for my Linn LP12. It made a very positive effect in reducing the noise floor and adding focus.

Very highly recommended.

mulveling's avatar
mulveling OP
1,895 posts
 

+1 Townshend seismic platform. Improved the sound of my Rega P8 as their sales guy said, startlingly. I have a suspended hard wood floor over a crawl space.

Interestingly though, the platform actually created footfall problems that previously did not exist. When I spoke to Max Townshend about this (RIP) he was not surprised because of the frequency of his pods and footsteps interacting. He said the solution was to either live with inferior sound without his platform, or put the platform and table on a wall mounted shelf, which thankfully fit nicely and got the approval from the boss for it since it looks like it is almost sitting on top of the credenza where my other equipment sits (on top of Sympoium roller blocks). I guess I was solving multiple problems like @mijostyn was talking about.

@sokogear Yep, a suspension alone (whether SOTA, Townshend or other) is not enough to guarantee immunity to footfalls. A large enough displacement will still excite the suspension, which in turn can excite the arm + cartridge resonance, which will certainly flap the woofers and other nasty stuff. My room here is also a suspended wood floor over a crawl space. We appear to have very similar use cases :) It was a combination of rack bracing, hockey puck feet, and Townshend platform that got my setup "effectively" impervious to footfalls. The newly braced rack reduces maximum displacement enough that the Townshend successfully mops up the remainder. They really have to work in tandem (a wall shelf would be very similar in function to my rack bracing). And the acoustic feedback is also now also solved well enough -- yep they’re inter-related to some degree.

@mulveling, I am not sure why you had so much trouble with the Sota. Did yours have the magnetic thrust bearing? Eclipse drive? I did have an issue with feedback at a very low frequency with the Cosmos. It turned out to be the three chambers acting like a Helmholtz resonator. Putting a skirt around the plinth closing off the cavity below the turntable fixed that problem. Otherwise, I have been totally pleased with the table. I also have an ultimately stable cabinet on a concrete slab. The subwoofers remain fixed with the above test regardless of anything else going on including the 10 year old. As for sound quality, it has none. Turntables are not supposed to sound. Any differences are usually easily proven to be from tonearms, cartridges and adjustment.

@mijostyn This is the older series Nova V (originally a Star III), not VI. No eclipse, no magnetic thrust. I was pretty bummed because VI was announced not long after I got the V rebuild done. And the VI upgrades indeed appear to be quite substantial. So now I have this V that’s still really nice but kind of a bummer when I think about it.

Sure, I didn’t give the Nova V a fair shake in this room, and I’m starting to suspect its suspension needs adjustment. If the tension & leveling on the 4 springs isn’t EXACTLY right you get all this jumpy side-to-side movement on excitation, which is really bad. Though I’m sure it would work well enough now with the braced rack. However I’ve already gone through a number of cartridges / arms / phono stages in this room and feel I’ve got a good handle on what each part contributes sonically -- previously went through the motions with these same parts in the main loft rig, too. The SOTA sounds really good but I’m simply preferring the Innovation Compact these days.

I had a Silent Running Audio Ohio Class isolation platform built for my Linn LP12. It made a very positive effect in reducing the noise floor and adding focus.

Very highly recommended.

@ghdprentice My friend has his HR-X on an SRA and it worked wonders for him. But he’s got an extremely rigid massive rack on concrete slab. Totally different use case to this room. I can pretty much guarantee any HRS / SRA / CMS platforms will not "move the ball forward" for the significant issues posed in this room. They have to help absorb a relatively large displacement. And that requires movement (a suspension). Unfortunately I don’t see those 3-layer vibrasystems rubber feet doing the trick here, either.

slaw's avatar
slaw
21,396 posts
 

Long time fan of springs.......done right. Have several Townshend products and a Rock 7.

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