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):
What Underperformed:
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.
It is my use of the AT-616 footers as demo' items to show others the benefits of suspending their own speakers that has been instrumental in convincing the speaker owners there is more to be attained from the set up for owned speakers. This has extended across Speakers with a Box/Cabinet Design and ESL's. The 616's are Holy Grails to find readily available in reasonably good condition and in quantity's to suit a Speaker Support. Townsend Designs and Gaia Designs are alternatives adopted and used in conjunction with a Sub Plinth, by individuals who have felt the need to maintain the good impressions made. I will state again, the best impact I have had as a footer under a TT and CDT > Valve DAC is when using Solid Tech 'Feet of Silence'. There are footers that are a close mimic to these as method top create a suspension footer and are much more affordable. I encourage others to investigate the alternate options readily available. |
@boothroyd Yes, a good observation -- I used to be optimistic the CMB itself could help provide isolation. However, my observations across the range (Innovation Compact, Wood, Master) are that it does not provide effective isolation. I think the issue is that there’s only compliance in exactly direction: straight up & down. It’s still a rigid bearing in every other sense. Even where there is compliance, it doesn’t exactly operate like a mass-on-spring. The CMB’s function is to reduce bearing rumble and eliminate the ball & thrust plate wear, which it does brilliantly: these are exceptionally quiet tables, and they easily take on massive platters with 5+ pounds of clamping. If it were compliant in directions other than straight up & down, it would be a poor turntable bearing because this would elicit a wobbly instability (ala the MagLev turntable’s platter). |
@mulveling Excellent post. Thanks for taking the time. |
Good post and I see that many of you are astute and have a good understanding of vibrations and their effects on our stereo gear. I want to add a few remarks to help everyone understand how best to isolate their gear. Springs isolate and rubbers dampen. A spring/mass system has a dynamic response curve that can be expressed as a ratio of input vs output across a frequency range. Beyond the natural frequency of the spring/mass system the response ratio becomes less than one. That means the vibrations going into the spring/mass system are reduced coming out. I isolate my gear with spring rates that achieve a Natural Frequency of 3 Hz, or there abouts in order to isolate my gear at all higher frequencies. It is easy enough knowing the mass of a stereo component to calculate the spring rate required to achieve a system natural frequency of 3 Hz. I have never seen a Townsend speaker platform in person but I'm sure that is what it does. Rubbers dampen. I know, we often see the term "rubber isolators" but that is not entirely accurate. Dampers reduce vibrations- especially important around the natural frequency of spring mass systems since the system can go out of control at its resonance point. But dampers also cause phase shift. This phase shift property of rubber is why we hear tonal variations or colorations. Sometimes these colorations are helpful and sometimes they are undesired. Nevertheless, all of the spring/mass systems of our stereo gear need dampening. The problem for me is I am not smart enough to determine the best dampening materials or amounts to use beforehand with calculations. I have to use the trial and error method or what we call experimentation. In most cases I found that isolating each of my stereo components with springs and then utilizing the factory supplied feet for dampening is sufficient. So I have each component on a wooden or delrin board supported by springs. In the case of my Sota turntable, I have it standing on a carbon fiber board supported by Isoacoustics Orea feet. After much experimentation with various materials I found this was the best solution. Yes, I was surprised by how much even my Sota is affected by the base it stands on. It has never been susceptible to footfalls or woofer pumping, but the tone changes based on the stand it is placed on. Since the Sota turntable suspension has a natural frequency of 3 Hz it cannot be placed on a spring isolation platform. A double spring/mass system would be a total disaster. I built my own speaker isolation platforms a few years ago using springs and butcher blocks. I got 48 lb/in springs from McMaster Carr and four per speaker got me a natural frequency of 3.1 Hz for the speakers I had back then. I was amazed at the difference in the sound on my suspended floor that isolating the speakers made. Eventually, I bought the Isoacoustic Gaia footers to try on my speakers. The speakers sounded better with the Gaia footers although they did not isolate the speakers from the floor as perfectly as my spring platforms. Why? The Gaia footers add dampening and this made the tonal balance of my speakers more pleasant. I moved my spring platforms to my home theater subwoofers. They make the bass deep, clear and crisp. To sum up, it takes a combination of isolation and dampening to find the optimum sound. I do it by putting each of my components on a spring loaded platform for the isolation part and then dampen the component at the base- in my case typically the feet supplied by the manufacturer. But experimentation with other dampening materials for each component may yield a better solution. PS. I'm amazed at the number of expensive high end turntables that lack any sort of isolation, or just a minimal amount of isolation requiring the consumer to spend yet even more money on a highly engineered isolation platform. If your turntable lacks a spring isolation system then build platform yourself and save yourself some money. You can find natural frequency calculators online for spring/mass systems. |
@tonywinga Another great post. Thank you. Regarding your statement, "A double spring/mass system would be a total disaster.". Since products like Oreos are damped isolation devices as you stated, would a set of those beneath a good platform which supports a spring type suspension turntable be detrimental? |
I’ll defer to @tonywinga for better explanation since he knows far more about this topic. But yes, I was aware one should never stack springs -- since their resonant frequencies can interact in very detrimental ways (huge displacement amplitudes when excited) -- I believe this has to do with the constructive & destructive interference nature of waves. My old dealer actually warned me of this when I first got into vinyl. So you should never, for example, put a SOTA turntable atop Townshend springs. I don’t believe stacking "squishy" damping interfaces like Orea feet suffers the same problem. Or at least, not severely enough to be of concern in typical use cases. I also don’t believe combining springs with damping devices is a problem -- in fact that’s a great approach! The main issue would be loss of stability when over-stacking -- don’t risk that expensive turntable toppling over! Technically, my turntable's full vertical support stack is: @tonywinga I would like to better understand the actual differences between damping devices and mass-on-spring systems. Doesn’t a spring system act "kind of" like damping above its resonant frequency? Or is there something else going on? And don’t damping interfaces also have resonant frequency? Thanks!! |
Just like in life- too much of a good thing can be a bad thing. Too much dampening can deaden the sound. That is especially true when working on room reflections. Too many reflections muddy the sound but too few makes the sound dead/dull. If you look at a chart of a spring mass system, the response ratio is about one below the natural frequency, then wants to shoot to infinity (constrained by physical limitations and dampening) at the resonance point (the natural frequency) and then falls below one and lower as the frequency input goes well above the natural frequency. So the spring mass system is absorbing the energy that is being put into it via airborne or mechanical vibrations through the floor. Think of a car. A car’s suspension system is simply springs. The shock absorbers are pistonic dampeners that keep the car from bouncing at its natural frequency while driving down the road. If you have ever driven over an old bouncy suspension bridge at just the right speed the spring action of the bridge can interact with the car’s suspension and make for quite an exciting ride because the car’s suspension will interact with the bridge. You might wonder why then if speakers are sitting on springs for isolation from the floor shouldn’t they start bouncing around and dancing across the floor like an out of balanced washing machine on spin cycle? They don’t because the spring suspension system is tuned for a natural frequency around 3 Hz and speakers are not typically able to go that low. Also, the mechanical energy output of the speakers is still way below that crazy washing machine on spin cycle. One more thing before you I start to annoy you all. A turntable tonearm is also a damped spring/mass system. The stylus in mounted to a cantilever which is mounted to a spring in the phono cartridge. The cartridge also has a dampener- typically a tiny o-ring. Phono cartridges have a compliance figure- that is the spring rate. The tonearm has an effective mass. It is not the same as the total mass of the tonearm and counter weight because the tonearm is mounted on a pivot. Knowing the compliance of the phono cartridge and the effective mass of the tonearm (always provided in the manufacturers specifications) one can calculate the natural frequency of a phone cartridge and tonearm system. Why is that so important? The goal here is to have a system natural frequency around 10 Hz. That’s because if the record has a warp- that is at 0.5 Hz (33.33 rpm) or 0.75 Hz (45 RPM) we don’t want the tonearm to have a resonance response near that frequency. And on the other side- the music frequency response starts at 20 Hz so we do not want the tonearm to respond at that frequency either. With the wrong set-up the tonearm will fly right off the record. Been there, done that. |
@mulveling One very important material that is being overlooked in your list of Materials, is the B25 Panzerholz (Densified Wood), it is the most upper layer of the Tiers produced and is the one used to support all of the critical mechanical components required for the TT to function. It is for the best, to not overlook the magic that this material brings, when used for the role to connect all the critical mechanical operating parts together. I would even encourage as an investigation that Densified Wood to be used as a exchange material for the Base of the Sota TT. The Link will give an indicator as to the values offered from a Phenolic Impregnated Densified Wood. https://www.lessloss.com/page.html?id=80
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The 1.5" thick brown wood layer in these Clearaudio Innovation and Ovation tables is panzerholz :) I’ve been admiring the Taiko audio panzerholz platforms. And I’ve definitely wondered if a nice slab of panzerholz atop the Townshend platform might be a good idea. @tonywinga Yes, I was aware the tonearm mass + cartridge compliance forms its own spring system, which can be difficult to deal with. Even when you’re right in the "ideal" 8 - 12Hz range, what they don’t tell you is that footfalls (etc) can very easily excite this resonance until you’ve properly addressed structural issues and isolation in a setup. I could observe this excitation very plainly -- by both sight and sound. Finally now with rack bracing, the Townshend, and (to a lesser degree) hockey pucks, this excitation no longer occurs :) Probably the worst case of feedback I’ve ever observed, even worse than this small room setup (before current solution), was with one of those Clearaudio full-magnetic bearing tonearms ("Concept", "Clarify", and "Verify") on a Clearaudio table, on a suspended wood floor, near the speakers. The magnetic arms act like their own spring system, and good god their interaction with other non-ideal system factors is just pure nightmare fuel! The hybrid-bearing "Magnify" arm (rigid in one direction, magnetic in the other) was a LOT better in this regard, at least. It looks like Clearaudio has either discontinued or de-emphasized these models in their line -- no surprise to me!! |
@mulveling This conversation for myself is now heating up, P'holz gets me all fired up. More importantly, I retired from building a system many years ago, and took on the task of working with interfaces that the system is dependent on, Electrical, Mechanical and Acoustic have all been thrashed out. This Subject under discussion on P'holz, is where I am now at with a New Material being utilised for Mechanical Interfaces and it is superseding all other choices for materials that are in use. The Taiko Sub Plinths are very good in my view, as they are P'holz, but are even better for one other thing, they really show how much money can be saved when sourcing the Panzerholz Material B25 Cross Grain Structure oneself. If a Fibonacci Arch is routed into the acquired board of P'holz, then the Taiko is almost mimicked. By acquiring the P'holz oneself, they can be assured the Spec' for the material is the one that is most desirable, as tests available to be seen to confirm this. How the P'holz is acquired and how much is to be paid is for oneself to decide on, getting the Spec' correct is very important. As a guideline my last purchase of the same P'holz as above was for a Board of a dimension 2mtrs x 1mtr ( 6' 8" x 3'3") which cost £850. This could be cut to produce 10 Boards @ 500mm x 400mm ( 20" x 16"), coming in at £85 per Board that can be used as a TT's Plinth, Plinth/Chassis or Sub Plinth. I have been using two Tiers of P'holz as a Sub Plinth, seated on and separated by AT-616 Footers. Depending on the weight of the Audio Device, I have a selection of footers to be used to separate the device from the Top Tier. This support method has been taken to other homes as well and loaned for demonstrations, it is a unanimous agreement that betterment is to be had when utilised. Usually the assessment is that unidentified smearing is discovered as having been removed, as it is replaced by new insights to detail being presented, that is a very attractive outcome as the initial observation. The Sub Plinth Assembly has been used under a variety of different Drive TT's, where it really shone in a unexpected way, was when it elevated a Garrard 401 to new heights. The method has also undoubtedly honed the presentation for the better from other TT's. A few who have been present during Dem's and have an interest in P'holz are now using P'holz as Sub Plinths in their own systems. There has been similar outcomes, but not as noticeable when used with CDP's and CDT's > DAC's, the biggest audible tidy up being when Valves are present in the Digital Device. A Valve Power Amp' that had been Imported and demo'd at a local HiFi Group event was considered to be mediocre, but OK for the retail price. When put on the P'holz Sub Plinth Assembly the Amp' become much more gathered in the lower registers and was quite unrecognisable, as the Mid's and Highs were very present as a result. I will suggest two uses for P'holz in your system, one will be easy to accept, the other a little more difficult, but very doable. The idea of the extra tier added to the Townshend Sub Plinth, is the easiest to accept and will in my view be very valuable as a addition. If the material used as the additional tier is a Phenolic Resin Impregnated Densified Wood, that is produced with a Cross Grain Structure for the laminations, a compression to 50% of the original thickness is also desirable, there are other Brands of Phenolic Resin Impregnated Densified Woods that achieve this, but P'holz B25 is meeting this Spec'. Note: It is not just the Densified Wood Material that brings on the magic, it is also the footers used as separators. The P'holz can be tweaked to a much more personal taste through trials on different footers. As stated in a earlier post, I have found the Solid Tech 'Feet of Silence' to be ideal for my unique preferences, there are much cheaper variants of these that are worthwhile trying out. Another friend has settled on 'Sorbo Hemispheres' as their choice for a Footer, and another is using Knock Off 'Stillpoint Ultra 6's'. Trials will bring one to their own selections to suit their preferences. If the added tier is produced, I feel that there will be a giant step taken for your TT, to become a rival to the advanced in design sibling the 'Wood'. The next suggestion, and maybe not too easy to digest, but one I can't but help feel will transform the good impression further is to investigate the TT's Sidebar Tonearm Support. I have been involved in experiments where the P'holz has been produced as a Headshell and a mount for a TA, (not a design that resembles a conventional Base Plate) Each has been A/B compared to previously used methods and each new method for a mechanical interface, has added something very special to the sonic. Note: These changes are small, but are wanted to be maintained as they add to the attraction of the listening experience. If the Sidebar can be swapped out for the B25 material, I do believe there will be a WTF moment from the impression being made. Additionally, if this route is taken and a machining service is utilised to help produce the items, do ask for any waste materials to be turned into Cone Footers, this will not be regretted.
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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.
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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. |
"Then we have the unknowns:
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 |
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. |
@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. |
Thanks again, @tonywinga and @mulveling |
Hi @mulveling Would you mind telling me what size your Seismic Isolation Platform is? I have an Ovation but am thinking about getting an Innovation Wood, but I don't know what the footprint of the Innovation spiked feet is. Clearaudio only says what one needs for the the overall space (i.e. 19" x 19") but that includes the plinth, arm board, everything, so I don't really know the minimum size I need for a platform to set it on. |
@dwette My platform is the standard Size 3 (the largest):
It's a little tight in the 16" dimension, but works. I inquired about a custom sizing but since it would be extra cost and wait time I just went for the standard 3. The way I have it configured in pic does a reasonable job centering the mass, so that only a little bit of leveling adjustment was necessary. |
@mulveling Thanks so much for the quick response. I assume, there is more flexibility in the 20" dimension? I have a 16.25" x 19.5" platform now, and I could probably get a HRS E1X 19″ X 17″ on loan from my dealer to try. IOW: are the three feet equidistant, such that 16" x 16" might work (barely)? Actually, if you can measure the distance between the feet that would be perfect. :)
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@dwette its footprint is an equilateral triangle where the sides are just under 15" each (including the steel pad spike cups). So the "height" of the triangle would be just under 13". So, 16" x 16" should work. It is indeed a 12" Universal. I had it leftover from my Master Innovation, since I prefer FR64fx, FR64S, and/or Graham Phantom Supreme there. It looks cool on the Innovation Compact, but I’m not sure if there is a real performance advantage over the 9" version. |
@mulveling This is great information. I really appreciate it. I may come into a windfall and am considering an Innovation Wood Black/Piano Black with black 12" Universal. I already have a Lyra Atlas Lambda SL, so that should be a killer combo. You helped me establish that I can actually site the beast, so I am in your debt, so to speak. Thank you.
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@dwette Lovely! My experience is that this Universal 12" arm seems to do best on cartridges with a dynamic, vivid sound with good treble energy (or even a bit extra). My Koetsus are a no-go on it, but it does excellent with Ortofon A90, Shelter Harmony, and even Benz Wood SM. The Lyra might just be an amazing match! I’ve come to appreciate the Innovation tables more with time, and of course as I provide better structural isolation. Started with an Innovation Wood 10 years ago, and am sorry I sold it. They all have an exceptionally quiet noise floor and very clean sound to go with the great looks. |
@mulveling Thanks for the feedback. I already know the Lyra I have is an excellent match for my 9" Universal so I expect the same or better with the 12" :) |
@mulveling I have sent to you a 'PM'. |
@thr1961 This thread has motivated you to investigate options on methods that can be used for mounting your very expensive recent purchase. My experience is that the presentation and level of perception of the presence of the produced micro-detail, micro-dynamic and coherence of produced frequencies, is able to be controlled to a particular level of performance through creating a mounting for the TT, that assists with removing the environmental impact on the TT. When the TT is able to work free from being effected by ambient energy transferral, a Magic is discovered, and a condition is created that is not wanted to be undone. I encourage further investigation, and suggest the Townshend Platform is another step, may be rested at for a period, but not the final step! |
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@mulveling thanks for all your prior help answering questions. I ended up getting the Innovation as I hoped to. I bought the Piano Black version, with the 12" Universal arm. I kept the 9" Universal from my Ovation and bought a Lyra Atlas Mono for it. I also got a HRS R3X isolation base configured specifically at the factory for the Innovation. This is all a massive upgrade from my Ovation on an isoAcoustics Delos, especially in terms of lowered noise floor, bass response and accuracy/stability of soundstage.
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