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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
8,208 posts
 

When you stack springs you create lateral instability, bad news for turntables. The Sota turntable was special because it was the first turntable to hang from it's springs instead of sitting on them like the AR XA or the LP12. This is also the method copied by SME, Avid and the Basis Inspiration. Hanging the turntable is a much more stable system. Only a suspension tuned to less than 3 Hz will isolate a turntable from environmental rumble. Sota also uses a magnetic thrust bearing. It is compressed by the weight of the platter to a very high frequency and damped by very thick bearing oil. As @mulveling suggested it is not in any way a suspension that will isolate the turntable from anything as it does not include the tonearm and cartridge as well as the frequency is too high. This is the argument against using such a bearing as it detaches the platter from the tonearm in the vertical direction. Functionally it does not due to compression and the oil. 

 

tonywinga's avatar
tonywinga
844 posts
 

My Sota Nova VI has the magnetic bearing.  Much quieter than my previous Sota Star V.  I thought the Star was quiet and what I was hearing was groove noise because the noise seem to vary from record to record but that noise is gone with the Nova.  Further, I have the Eclipse Motor and Roadrunner speed control system.  It works really well but I wasn’t too sure until I figured out how to use it.  One button turns the motor on/off and also toggles the speed between 33 and 45 rpm.  I had to learn to hold the button down for a count of 2 when starting the motor.  Otherwise, the speed wants to toggle to 45 rpm.  The button has to be held down for the count of 2 when turning the motor off.  I knew that and once I realized the same holds true for turning the motor on everything was fine.

I have a set of Sota cones as well as the Sota rubber feet for the turntable.  I experimented with both.  For me the sound is better with the rubber feet.

robob's avatar
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robob
197 posts
 

"Then we have the unknowns:

  • Just how rigid is that rack of yours?
  • What is the structure of your floor -- this matters more than what’s on its surface. If your floor is not rigid enough, then it won’t be enough for your rack to be rigid. That’s where the wall bracing comes into play.
  • Close proximity between the table and 1 or more speakers, ESPECIALLY a port, can be problematic. Applies doubly for a subwoofer. I don’t have a subwoofer to contend with in any of my systems. Do you have a high pass filter on the main speakers, or are they run full range? If filtered, that could at least protect your mains from certain kinds of dangerous feedback issues (woofer flapping, amp clipping), though the subwoofer will have to be robust enough to deal with it."

Sorry if I was not clear. Floor is padded carpet over concrete so footfalls are not an issue. The turntable beng close to a speaker is the worry.  The l&r speakers run full range.

Stil waiting on Tri to ship my arm. Table has been sitting at the dealer for weeks.

Y’all take care,

Robert

cd318
2,636 posts
 

This is an interesting subject and quite a difficult one to draw any generalisations in.

For what it's worth, back in the 1990s I experimented with various wall racks for my turntables and found that none of them really helped to the degree I had hoped.

The wall in question was a solid brick dividing wall and various mounting methods were tried.

Unfortunately, because I live near a fairly busy main road, these wall mounts only served to magnify and transfer the tiny movements of the wall itself to the turntable and eventually the stylus itself.

This proved especially damaging when using a turntable which featured a sprung suspension which can only cater for vertical deflections in a certain frequency band.

Anything below or above this band caused readily heard problems which were made worse by wall mounting.

 

Ultimately, I think whilst nothing beats a solid concrete floor, or a sold brick wall, and even if the equipment itself has some form of isolation built in,  the quietness of its location is the main factor. 

If your home is subjected to regular outside vibrations, the best you can do is to ameliorate some of these, but I don't know any way of eliminating them completely.

pindac's avatar
pindac
2,419 posts
 

@cd318 My evolving experiences with trialing methods to mechanically isolate my system and especially the Source of the system has always been in a environment where Concrete Floors and Brick Walls has be present.

I have never been exposed to very busy Transport that is in close proximity.

The methods I use today are different to the ones I used in the past at different homes. Is the earlier methods inferior to today's used methods?, or is the different homes/environments requiring a different approach to the methodology used for a support structure and the materials used?

I have stated in the past, experiences have shown to me there is not a ubiquitous solution for all environments, and then there impact on the sound from using materials, the produced sonic is one that can be altered/tuned, and when confident with toying with structures, the sonic can be produced to be close to the preference of the end user. This extended practice will equate to differences for selections of materials and how they are configured within a structure. 

I agree that the ambient environment being quiet, as a result of not being a hive of activities is a valuable asset. Also the quietness of the room dedicated to the audio experience is critical, this is where Room Acoustics comes into play and working with the space to minimise the impact of the sound produced on the sound being produced. All of the interfaces that are present whilst using Audio Equipment have a importance, probably all are equal.

Well thought out Electrical Interfaces can be extremely valuable at producing a detailing that is detectable/perceivable within the produced sound.

Good choices for materials and the positioning within the Room, will manage  unwanted sound, which can generate new sound or colour produced sound.

 The choice adopted for mechanical interfaces are broad, and some of the requirements that are working are shared within this Thread.

The best is to be had, if all three of the above are given considerations. 

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