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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
mulveling's avatar
mulveling OP
1,928 posts
 

To be clear, the wall in question here is an outside wall. There is indeed a lot of vibration energy going through the walls too, but the Auralex foam tile I’m using to couple the rack to the wall helps reject a lot of this. It’s a give-and-take between how tightly coupled the rack is for support, and how much vibration transfers from the wall. I still use a CMS Black Platinum filter for the top self which is NOT in contact with the bracing material, and I’m certain it’s doing a great job filtering out the additional wall energy. The main net result from wall contact here is it effectively damps and attenuates footfall shockwaves.

I’ll say again the Minus-K looks amazing. If I got one, I would still keep this rack bracing arrangement. Any isolation platform, whether passive or active, is going to work better on as a solid support as possible. The solution I have now, culminating in the Townshend platform, finally meets my needs for this system.

I’m not advertising this as a one-size-fits all solution or a "reference" system of any kind. It’s simply scaled down version of my main loft rig (with a lot of hand-me-down components), for enjoyment in my girlfriend’s (challenging) suburban home. I could NOT get problem free vinyl sound in this home (even tried different rooms) until I hit on this combination of isolation elements. Previous attempts experienced the whole gamut of ills, from massive acoustic feedback to the usual footfall skips. No warranty, implied or otherwise lol. 

LOVE the stories on hockey puck benefits :) Keep telling me about your rack bracing solutions too.

pindac's avatar
pindac
2,864 posts
 

Screed Flooring laid in Laboratories has additional measures put in place for certain Companies designs for how a Screed Floor is to be laid onto substrate materials. Certain Pharmaceutical and Research Companies, especially those turning over 40 Billion+ annually are taking vibration being noticeable in the Lab' seriously and are putting quite a lot of engineering research into pre-screed laying measures being in place that are serving to isolate the screed from the energies transferred through a buildings super structure. This is created by using substrate materials that are highly effective at stopping energy transferral to the Screed. 

I learnt of this as a result of having a good communication/friendship develop with a Quality Manager responsible for producing Laboratory Flooring on a project I have been involved in, when I was informed the Screed Floor was designed to be de-coupled from the structure as a means to minimise energy transferral and reduce vibration within a Lab', as well as Floor Finishing materials also being selected with this same goal in mind as well I was all ears.

I have this specialised Substrate Material at home and in use as part of a Structure on my system, it is assembled as a 500mm Deep Lamination. This has a Hard Foam Layer upon it and is topped with a 200Kg Granite Engineers Flat Plate mounted on it. 

Again not many are experiencing their Audio Equipment on this type of structure, and this has proved to be a killer to build, definitely a young mans sport, but also serves a role as a superb support for my Amplification and with another Tier Structure placed on it, works superb as a mounting location for an Idler Drive TT. 

I am sure I can go out and spend £1K+ on a version of a Support Structure for my Amp's, but I have no asurity the items utilised are able to come near the method I have evolved to having adopted, that has proved to be substantially less than the commercial route offerings.   

 

thr1961's avatar
thr1961
67 posts
 

Well, I have $20 worth of hockey pucks en route to my house. My back wall is external and load bearing, so I will be trying a variation on the bracing, getting materials as high on the wall as I can. There is a window that will limit it slightly, but I have everything I need so it's just my time!

For what it's worth, my rack is from Core Audio designs and is both insanely heavy and well built and each level is treated with dampening materials inserted in the base of each shelf. This means, of course, is that I have to take everything off the rack to get pucks underneath it, unless I can line up two trustworthy power lifters to pick up what is probably 600 pounds of gear and rack!

If steps two and three don't do it, I have the option of trying out a vibraplane. I may alsto try the Townsend, but plan to take it step by step. 

whart's avatar
whart
3,050 posts
 

I certainly don’t advocate getting all spendy on a Minus K if you can solve a footfall problem less expensively. I couldn’t for a couple reasons- one, the structure of the house- it is an 1880s landmark that was painstakingly rebuilt from the original wood (longleaf pine and shiplap) but the floors are springy and the walls could not support the weight of the table (245 lbs) even with a steel frame installed. I had a structural engineer come in to advise. Note that the room where the hi-fi is located has been modernized- downstairs is all original wainscoting, shutters, transom windows above the interior and exterior doors, elaborate door frames and pocket doors, etc.

What I did was install a subfloor beneath the front end area- made of two layers of marine ply with a barn mat on top-- thing is dead level.

The MinusK does allow you to adjust for an uneven floor but it adds another variable and to top that off, my linear tracking arm needs to see a slight tip up in the front right corner--it’s a very fine adjustment that is made by playing with the arm and watching its travel-- something a level or other measuring device would not enable me to zero in. The net result is that I can play this table without issue. Here’s what it looks like using the MinusK stand (which is also adjustable). There is an HRS platform between the Minus K and the table.

pindac's avatar
pindac
2,864 posts
 

The Plinth underneath the Racks is something that I have done.

The Racks in my set up are mounted on two Steel Sheets 1100mm x 700mm x 12mm. The two steel sheets also have their own support Structure underneath produced from Granite and Hard Foam. It is this foundation that was the game changer for me, the improvement that was noticed has been notable and will be maintained. 

The fact that Densified Wood has been offering real improvement on the top of the Rack System, leaves the question does the inclusion of Densified Wood at the Base of the System produce a further attraction to how the structure performs.

A friend and I are also seriously considering a Rack Produced from Densified Wood, but for me there is a deep ingrained sentiment attached to the Racks I am using.  

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