turntables; high level anti-resonance----active (Herzan) platforms, Minus K, air bladder (Stacore) platforms, or others?
- Thread starter Mike Lavigne
- Start date
I've been running my Stacore under my direct rim drive tt for nigh on 3 years now. It combines mass loading (93kg), pneumatic isolation, rollerball isolation, and some secret sauce CLD goodness (slate mixed w something special). I initially installed it directly on my floor, an existing 150 yr old flexy 50'x35' span timber floor w new ply top layer nailed/glued on. It proved to be a huge advantage in my analog reinstall.
I've then progressed to plonk the Stacore on a 50kg single tier inert slate stand (a sturdy wall shelf was my first choice, but the ergonomics didn't permit this).
So, I've been able to compare three methods of isolation for my tt (in addition to my original data points where Symposium Acoustics stand beat my previous rigid stand, and Stacore on the floor beat my Symposium stand).
That is, tt on Stacore correctly inflated, deflated, and tt purely on inert slate stand. The latter A/B is not one I want to go thru again, necessitating moving the whole tt, and super heavy Stacore.
So, it's not really close. The tt purely on a 50kg inert slate stand sounds perfectly fine, but a certain hardness to the sound. My guess is the tt would sound better back on the Symposium. The tt on deflated Stacore sounds better, reasonably subtle uptick, but a more resolute sound emerges...the Stacore rollerballs likely are helping, as Rollerblocks did in my Symposium. The Stacore fully operational ie inflated, now the magic is happening again...resolute and detailed, instrumental lines way easier to appreciate, bass much better defined. Upon the slate stand, and last degree of improvement kicks in, although this is more to do with further isolation/distance from my floor-firing subs.
I've then progressed to plonk the Stacore on a 50kg single tier inert slate stand (a sturdy wall shelf was my first choice, but the ergonomics didn't permit this).
So, I've been able to compare three methods of isolation for my tt (in addition to my original data points where Symposium Acoustics stand beat my previous rigid stand, and Stacore on the floor beat my Symposium stand).
That is, tt on Stacore correctly inflated, deflated, and tt purely on inert slate stand. The latter A/B is not one I want to go thru again, necessitating moving the whole tt, and super heavy Stacore.
So, it's not really close. The tt purely on a 50kg inert slate stand sounds perfectly fine, but a certain hardness to the sound. My guess is the tt would sound better back on the Symposium. The tt on deflated Stacore sounds better, reasonably subtle uptick, but a more resolute sound emerges...the Stacore rollerballs likely are helping, as Rollerblocks did in my Symposium. The Stacore fully operational ie inflated, now the magic is happening again...resolute and detailed, instrumental lines way easier to appreciate, bass much better defined. Upon the slate stand, and last degree of improvement kicks in, although this is more to do with further isolation/distance from my floor-firing subs.
As I often say, something can be true or false depending on the frequencies being addressed. I can assure you active tables can cancel intrinsic vibrations - for example they cancel the intrinsic vibrations induced by the scanning and focusing mechanical systems in atomic force microscopes where we do not address micro-vibrations but nano-vibrations. The rotational speed of a turntable is around half an hertz, well bellow the range of action of the the active suspension, but probably the motor generates other frequencies.
IMHO there are too many uncontrolled particular conditions that can affect the performance of isolation devices and we can't have firm rules on their application. I got the TechDas custom rack with the AF1p, but otherwise would love to try an active table under it.
Can we know what toneram you will be using with the AF0?
David, i'll only comment that my comment is not in any way a criticism of the AS-2000. there are good reasons for a separate plinth and motor box in a string drive design. it isolates the motor from the plinth. it's a valid approach.That's actually untrue Mike. Going in I knew very well that the Herzan is a bad idea for any turntable, I explained discussed the reasons why in several threads here, long before the AS2000. Christian already had a negative data point with his AF1 and a Herzan, exactly the same outcome as with AS2000. Another invalid data point?
What the heck is "self noise" anyway? You haven't even seen an AS2000 how did you evaluate did come up with this evaluation?
david
self noise relates to resonance sensed from gear sitting on an active device. if the sensors detect resonance inherent in that piece of gear then the active device will attenuate it, but since it will not go away a loop is created which increases the noise, not reducing it. most tt's will generate self noise as that is a method to drain off resonance from the plinth/platter. but some turntables don't generate self noise. some is inherent in a design approach but with some designs it's not clear what might happen.
i have no illusions you will agree.
I'm following this thread with interest. There seems to be a lot of talk about "self-noise" that's theoretical, not empirical. I've found that a very useful way to assess whether there's any noise that can be pernicious, regardless of source, is the simple use of a stethoscope. Folks, we're spending 10K and up for a cartridge and sometimes even more for cables! Surely anybody who calls themselves an audiophile can spend 50 bucks to buy a stethoscope on Ebay. Listen to your turntable base or shelf with the motor on or off and you'll know right away if you have noise generated by the gear of interest. You may not hear noise that's -150dB, but you'll not have any difficulty hearing noise that has more likely will an audible effect (<-60dB easily, probably even up to -90dB in some instances). But be careful what you wish for! Don't be surprised if you hear noise from your hallowed turntable base from your refrigerator compressor in the next room, or from your air conditioning unit. This is such a simple test that there's really no excuse for not performing it. Once you hear noise, you can then take any number of approaches to ameliorate it. I've found that mass (1" stainless steel plates) combined with constrained layer damping (neoprene, thin O-rings, other?) on study shelving is quite effective in many instances, and quite inexpensive compared to 10K+ active devices. My point is, a stethoscope provides real concrete evidence of noise that can be effectively documented. You can always remedy what you think is a genuine noise issue by throwing a lot of money at a solution (of which there are many), but doesn't it make far more sense to document it empirically first so you can then document its effective removal in an objective manner?
As far as stethoscopes, the common "old school" scopes have 2 heads (actually 2 surfaces- one each side of a single head; flat or a concave shallow bowl) that is sensitive to higher and lower frequencies respectively. The newer electronic stethoscopes (~$200) are remarkable and often contain dsp software for filtering or tuning of certain frequencies, Some even provide graphic output mapping to a smart phone so you can actually see what you are hearing!
As far as stethoscopes, the common "old school" scopes have 2 heads (actually 2 surfaces- one each side of a single head; flat or a concave shallow bowl) that is sensitive to higher and lower frequencies respectively. The newer electronic stethoscopes (~$200) are remarkable and often contain dsp software for filtering or tuning of certain frequencies, Some even provide graphic output mapping to a smart phone so you can actually see what you are hearing!
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I would also ask myself if the elimination of noise increases the perception of realism or natural sound from one’s audio system. Sometimes removing noise also removes musical information that contributes greatly to the perception of convincing sound.
sometimes liveliness in the room or vibrations in gear help rather than hurt the perception of sound quality. Sometimes absorption and dampening are detrimental to sound quality.
I think it’s a balancing act, a matter of fine-tuning. And people will have different opinions and different preferences about which is better.
sometimes liveliness in the room or vibrations in gear help rather than hurt the perception of sound quality. Sometimes absorption and dampening are detrimental to sound quality.
I think it’s a balancing act, a matter of fine-tuning. And people will have different opinions and different preferences about which is better.
Marty...what, simple objective evidence...this crowd 
IMHO, Marty is spot-on...
...on the other hand, you have to have some real residual hearing to make this simple observation; if not, well, your ego can be quite helpful validating your decisions
vbv,
a
IMHO, Marty is spot-on...
...on the other hand, you have to have some real residual hearing to make this simple observation; if not, well, your ego can be quite helpful validating your decisions
vbv,
a
Marty,
Unless we know exactly what we are wanting and/or are an expert in turntable development the stethoscope is excellent for medical use but IMHO can be improper and misleading for turntable optimization. First, most of them have a very poor bandwidth and high resonant modes, being extremely non linear. Second, motor and bearing energy must drain to somewhere - if you just listen to the stethoscope in the plinth you risk you are just modifying the noise spectra or even worst reflecting the noise back to the motor, where it will drain it to the plater through the belt.
IMHO a good sensor, such as inexpensive MEMS accelerometer is needed to perform such tests. See https://www.analog.com/en/analog-dialogue/articles/mems-accelerometers-as-acoustic-pickups.html# Unfortunately, vinyl and electromechanical aspects are not currently my main interest in audio - considerable progress has been made in this field since the last ast time I looked at it, looking for information about the accelerometers glued to the Krell Master Reference Subwoofer cones.
Sometime ago I helped a friend to set up a subwoofer. I carried a calibrated microphone , a Behring ECM8000 and a portable running REW. A local expert was using an hand held Iphone with a spectral analysis app - our measurements showed more than 7 dB difference in some frequencies.
If I do remember correctly, the TechDAS Custom Rack for AF1P is an
Artesania Exoteric Rack with a customized Krion platform on top.
The Accurion i4L active table has nearly the same size, than the standard Glass- or Krion turntable Top Platform.
I am using the Accurion active table between the Artesania Rack as such and the Artesania Top Platform with success.
Hi Marty,
Won't every motor and spindle in a bearing and moving or rotating mechanism generate some noise at some level? Is your point that yes, turntables will generate self-noise, but if the noise level is below a certain threshold, then we don't have to worry about it?
Hi Mike,
I think you are suggesting that if a turntable does not generate self-noise, then it is a candidate for active isolation. Do you have a self-noise level threshold in mind?
Won't every motor and spindle in a bearing and moving or rotating mechanism generate some noise at some level? Is your point that yes, turntables will generate self-noise, but if the noise level is below a certain threshold, then we don't have to worry about it?
Hi Mike,
I think you are suggesting that if a turntable does not generate self-noise, then it is a candidate for active isolation. Do you have a self-noise level threshold in mind?
The custom TechDas platform is not Krion - it looks to be more inert than the Artesania Krion platforms - according to Artesania it is a "Special Acrylic Damping made by special acrylic
crystal with an excellent absorption capability for any vibrations developed by Tech Das under
Mr. Nishikawa engineering especifications " It is much thicker and larger than the standard Krion ones coming with the rack. I should have weighted it on a precision scale to calculate the density before putting the turntable on it! Anyway it is also much more inert that the glass platforms. Curiously tapping on it with the finger knuckles makes a sound very similar to the Taiko Audio Daiza.
My floor is extremely firm - it is wood over a ground floor including layers of cement, sand and gravel - it is why I am staying with the TechDas rack as it is.
As I said this is an very interesting topic, everyone can have his own opinion. ddk and Nishikawa san are not big fans of active isolation. I discussed with Nishikawa san during the development phase of AF0 whether he would include active isolation in the design, He said no for the reasons I have listed before.
In order for active isolation to work, I think there are some requirements. First, the turntable should be a good quality one in terms of everything being relatively balanced and smooth, so intrinsic vibration is kept to minimum. In particular, the dynamic balance of the platter has to be close to perfect. Most platters are fairly heavy component, small degree of throbbing requires a lot of force to counteract. The counteracting force in most active isolation system is limited.
Some forms of suspension will help. If the turntable has rigid mounting, the vibration of the turntable is directly coupled to the active platform. The main purpose of active isolation is isolation, i.e. to avoid vibration of the environment to feedback into the turntable and is not to eliminate the intrinsic vibration. So Air Force One is a good candidate for active isolation.
I am keeping my current original version SAT arm for AF0. TechDAS is developing a high tech tonearm, I shall wait and see what comes up later.
Francisco and Ron,
I'll respectfully have to agree to disagree. In my view, any noise you can hear with a stethoscope = bad. No noise= good. To say some noise is good or that it needs to be there so it can "drain" properly is like saying, well, second order harmonic distortion from tubes is a good thing because it makes music sound better. Distortion is distortion and noise is noise IMHO.
I'll also have to respectfully disagree that "most" stethoscopes are "non-linear" and have "high resonant modes". (Where is that coming from?) It is true that the flat and concave surfaces have specific and limited bandwidth tuning intentionally since they are designed to auscultate specific contractile and blood flow turbulence events and anomalies like pulsations, murmurs, valve sounds and bruits. Fortunately, as an ophthalmologist, I didn't have to use them for cardiac evaluation (except for carotid bruits) since in general, I always sucked at it because I always found the typical hospital environment too damn noisy to make anything other than crude assessments! However, I've found that a stethoscope has given me very useful information for turntable suspensions as well as general gear isolation for over 40 years in the quietude of my room, but of course, YMMV.
I'll respectfully have to agree to disagree. In my view, any noise you can hear with a stethoscope = bad. No noise= good. To say some noise is good or that it needs to be there so it can "drain" properly is like saying, well, second order harmonic distortion from tubes is a good thing because it makes music sound better. Distortion is distortion and noise is noise IMHO.
I'll also have to respectfully disagree that "most" stethoscopes are "non-linear" and have "high resonant modes". (Where is that coming from?) It is true that the flat and concave surfaces have specific and limited bandwidth tuning intentionally since they are designed to auscultate specific contractile and blood flow turbulence events and anomalies like pulsations, murmurs, valve sounds and bruits. Fortunately, as an ophthalmologist, I didn't have to use them for cardiac evaluation (except for carotid bruits) since in general, I always sucked at it because I always found the typical hospital environment too damn noisy to make anything other than crude assessments! However, I've found that a stethoscope has given me very useful information for turntable suspensions as well as general gear isolation for over 40 years in the quietude of my room, but of course, YMMV.
Spot on, in my opinion. I have been using a stethoscope to tune my turntable for over a decade. And I also don’t know either where this <<"non-linear" and "high resonant modes">> is coming from. Noise, by definition, is always unwanted signal; though admittedly the proper removal of it can sometimes be very challenging.
Marty,
It seems I was not able to make me understood. I was no way telling that noise is a good thing in general. I was pointing specific cases where listening to noise with a stethoscope and minimizing it can be misleading. It seems me you miss the point that there is always noise in a system and the noise energy should be dissipated somewhere where it does not affect sound reproduction . This is particularly important in audio, where often poorly understood tapping and tactile tests lead to false conclusions.
Medical stethoscopes are a very well studied device since long. They were perfected to complement the ear morphology and their applications and their frequency response is well studied and published in many works - the subject become actual again due to the development of the electronic stethoscopes that you referred - it even became a fashionable subject for biomedical engineering student projects. IMHO their response is inadequate to audio and can lead to misleading conclusions - would we use an audio measuring tool with 20 dB errors? IMHO this is particularly important in a subjective hobby where differences are often minimal and our own biases can be determinant and measurements can induce strong biases.
Again, please note that I am no way commenting on your particular use and practice. I am just addressing the technical intrinsic problems and limitations of using a stethoscope in this hobby.
Just google "stethoscope" "frequency response". Hundreds of measurements available on the net. And they usually show good quality stethoscopes from known brands, not the $20 stethoscopes.
Stethoscopes are developed for specif frequency bands and weights to optimize their use in medical applications.
Yeah "where is this coming from" does not literally mean what you wrote is false - rather, it is irrelevant, because we are not aiming to take accurate measurements with such a device, rather a rough close-up of mechanical noise seeping into the equipment, similar to a basic microscope. I don't think it's hard to understand the basic concept and fundamental issue.
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