A Few Turntable Measurements using the RPM Android App

Very nice write up. Enjoyed reading how you used the meter. I’ll try one for IOS to see how it, works

I’ve played around a bit with the IOS app. Interesting new use for the phone.

I found that changing the oil in my spindle bearing and cleaning the belt on my Basis TT improved wow & flutter by 0.04%. :)

The Wow XXL does have adjustable speed, but it is not well documented.  There are 2 tiny buttons on the back of the table.  Each push of a button will either slightly raise or lower the speed.   I don't recall which button raises or lowers, so you will have to experiment.  This won't change variations, but at least will allow the RMP to get closer 33.33. 

Dear @kevemaher  : Good that you shared those measurements that speaks by it self what I knew of the Denon quality.

 

I still own two Acoustic Signature old top of the line TT's alog Denon, Technics, Luxman and the like. Inside the external PS in my TT's I can fine tunning its speed and you can do it with your table too:

 

"" The Wow XL is driven by an ultra-precise synchronous motor that employs a 20MHz microprocessor that provides “perfect” speed stability and fine-tuning. Two small recessed buttons on the back of the ’table allow ±0.1% speed adjustments, so you can dial-in the speed during initial setup. I checked the speed after I set up everything, and it was spot on. I checked it three weeks later, and things were still spinning correctly. It’s safe to assume that once you initially set the speed, you can leave it be without worrying—it’s always good to check speed if you move the ’table, though. The motor is extremely quiet, too. Fitting the belt was easy, and once the motor was turned on any twists were straightened out after a few revolutions. Two stainless-steel buttons are located to the left of the platter, an on/off button and a 33/45 button to easily switch speeds. Turn the turntable on, and a red LED blinks above the speed button until the precise speed is reached.  ""

 

 

Regards and enjoy the MUSIC NOT DISTORTIONS,

R.

I have to say that the RPM app should be bought before you spend a lot on a strobe. I have the manual Clearaudio Device - its' good but the App is just so consistent and sensitive. I used a spray can lid to place my phone on when i use the app (for decks without a weight with a flat top). Slightly off-topic but i very much doubt that the phone weight will skew the reading once the deck is up to speed what say you guys

 

My concern is that the weight of a cell phone placed eccentrically on the platter will per se skew the reading, especially for wow and flutter. Furthermore, is there independent evidence that the rpm readout is accurate? I thought there was some doubt about that. Repeatable, perhaps, but accurate to for example +/- 0.1 rpm? Or even +/-1.0 rpm? I dunno.

I can’t see how a small off center mass would alter the wow and flutter.... if the platter is level. But like "animal" above I also use a small plastic bowl over the spindle so the phone can be centered.

The app I’m using is called RPM speed and wow. Fun stuff. I used it to gauge how well my fishing weight platter mod worked. I glued four four oz lead fishing weights around the perimeter of the platter. I was careful to balance it by teetering it on a marble. Then I used the app to see the change. Went from 0.18 to 0.14 with the extra pound. Platter went from a massive 2.4 up to an incredibly heavy 3.4  pounds!  🙄  The table is a Music Hall 2.3, so fun to mod, and it needs it.

 Just did another platter comparison.  This time between an acrylic one which weighs about 2.4 and my modded steel 3.4 pound platter.  The sigma for the acrylic was 0.14 and the steel was 0.11.  Science!!  

I think I'll be returning the acrylic one.  Not enough room to add the weights and doesn't seem any quieter.  Looks cool though.  

How much weight can I add to the platter before the motor blows up and belts snap?  

I should point out that the RPM app has not been independently verified for rpm accuracy. As I reported above, the repeatability is good.

The WOW 2 sigma reported by the app has also not been verified. In particular, the method of calculating the WOW has not been described. For example, is it the standard way of measuring? Is it weighted?

I can say that this app is good for comparing turntables and modifications to tables. The absolute accuracy of the reported rpm and wow is unknown. I would find it difficult to compare findings from this app to manufacturer's published measurements.

@ossicle2brain One way to find out how much weight is too much is to add weight to the table, then measure the RPM and WOW with the app. Continue to add weight until the speed changes or the WOW increases. This will probably happen before anything breaks.

But be aware. Too much additional weight may cause long term damage to the motor moving parts due to the increased load. It is very difficult to estimate that without long term measurements or manufacturer's recommendations.

Gosh. My iPhone weighs nothing compared to some record clamps I’ve used. And I’ll bet NASA wished they had accelerometers as accurate when they put men on the moon. :)

Its just a fun app to play with. :)

 

..and then there is flutter.  Which I guess is just faster wow.  Maybe the DD turntables have more of that?  How do you measure that one and maybe it's more important then wow?

Great.  Now with an app we can be even more OCD about listening to music. I mean audiophilia.  Whatever.  

Measured my AudioGrail Garrard 401 with SPH grease bearing, PAC platter, Artisan Fidelity idler using RPM Speed and Wow app. Table was running for at least 4 hours.

Wow 2Sigma = 0.08%

@duckmanst3 Hi, I'm not questioning the accuracy of the hardware, although that would be nice to know. I'm concerned about the logic and math used to make the calculation. That info has not been published and probably won't be because (I bet) the person who created this app was doing it for fun, not for the rigor needed to develop a product for sale.

Yeah, using a phone for this measurement has little to no affect on the performance of the table.

Some belt driven tables take a long time to get to speed and settle, longer if weight is added. If he app starts before the TT has a settled speed, the measurement result will be invalid.

It cost so little to try. Give it a spin. :)

https://drive.google.com/file/d/1f5dal0O-pXY6Gk-0PMd5HyMvyHk5XyyO/view?usp=drivesdk
 

Duckman, I am talking about the weight of the phone being unevenly distributed on the platter. That’s not the same as a record weight that fits over the spindle, or as a peripheral ring. In a high quality TT the platter has been dynamically balanced. The phone would destroy that balance. Does it matter? I neither know nor care.

It’s obvious you don’t care :)

Here’s a simple test of your theory. Center the phone as well as you can using simple measurements and run the test. Then move the phone obviously off center by about 25mm and rerun the test. I did and saw no difference in results for speed or wow/flutter out to 2 decimal places. 

About platter balancing, I consider my Basis platter well made but I see no indication of it being dynamically balanced other than simply being machined accurately. 

Good.

@kevemaher  You said some belt drives need a long time to settle.  Is that because of the "rubber banding effect" of the belt stretching on start up?  

@ossicle2brain My Acoustic Sounds WOW XXL table is an excellent case. From a cold start, it needs a push on the platter rim to begin spinning.  One never knows when it is up to speed. There is no feedback. The REW app provides some idea. The app has a delay prior to beginning measurement. The WOW barely gets to speed before the measurement starts.

The motor used in the WOW has minimal torque, just the opposite to that of the Technics SL-1200  or the Denon DP-57L or DP-88.. I cannot think of a reason why AS decided to do this. I can't see an engineering reason.

There is a common rationale associated with the combination of a high mass platter with a low torque belt drive. The idea is that speed stability comes from rotational inertia, not motor torque. The Walker Proscenium, all Nottingham tables, and many tables of Germanic origin are examples of this approach.

What Lew said. Low torque motors transmit minimal vibration and noise to the platter (and all parts of the table) Some belt drives use tooth floss for example to further reduce transmission of motor artifacts while relying on inertial mass to keep the platter spinning accurately. 

I cannot think of a reason why AS decided to do this. I can’t see an engineering reason.

This is one of the eternal arguments among vinylphiles. In belt drive world, we have the light platter/high torque motor crowd vs the heavy platter/low torque motor acolytes. Then we have the idler/DD aficionados who jeer (privately) at both. Modern methods of speed control have leveled the playing field somewhat. My dirty little secret is that I finally couldn’t stand the ritual of having to push start my otherwise perfectly good Nottingham TT and so was driven to experiment with idler and direct drive. (On one occasion I nearly knocked the Nottingham off its wall shelf with my overzealous push start.)

@lewm I have not been able to find specs on the Nottingham or the Walker tables. It is quite difficult to make comparisons on table performance without basic speed and vibration specs. I will never buy a table again without seeing these specs.

One's ears are far less sensitive than the equipment used to measure table speed and vibration performance.

As is often the case, measurement is the issue. RPM is a continuous quantity only in the abstract. In all practical applications, it is an average. Maybe over a fraction of a millisecond, but that still is a far cry from continuous.

So the major issue, variations on the 10 - 20 KHz level, may be averaged out and not be addressed at all. Unless the specs indicate the time span over which the average is taken, the results don't mean much. As one of the greats from the glory days of audio once told me, "The best audio analyzer available is hardwired to your brain." (Jonas Miller)

I like the Nottingham sound too, which is why I built my air bearing with a 45Kg platter and a 1.8 watt motor.

@terry9 Like with many quantities, the speed aspects of turntable rpm can be described as a mean surrounded by skirts on either side. I say this with trepidation, because the turntable noise is not a stochastic (random) phenomenon. It can have resonances, for example. However, narrowing the width of the frequency spread and diminishing the signal from resonant sources is a worthy goal.

Some say that a turntable that has poor rpm control cannot bring out all the nuance that a high end cartridge can pick up from an LP. This reason alone is why some people are interested in the stability of the RPM. The human ear is not a good instrument to evaluate rpm. One may prefer one or an other method of rpm control because the sound of one is more pleasing than the other. Comparisons based solely on listening is obviously important. This type of comparison is not quantifiable by nature. Specs are there to provide a guide to potential users.

Engineers develop a product based on numerical specifications that the company's sales and marketing generates. Engineers use test instrumentation to measure and compare design approaches. Without a formal methodology and explicit specifications, engineers do not know what nor how to build a product. And importantly, when to stop engineering and consider the problem solved.

Measuring performance parameters of instruments is crucial to product development.

Any company that does not report these values via a spec sheet is denying the customer one way to evaluate and compare different instruments. Some customers need to see these specs because they provide a baseline for the performance of the instrument.

Not publishing a spec prevents that from happening. Often known code words or phrases are used to appeal to the emotions of particular enthusiasts. These are not specs. Perhaps some don't care. I do.

Replace the belt on the wow and measure again. Let us know what happens.

Hmmm terry, 45 kg is ...... like only 99 pounds, not even a hundred.  Watt?  1.8?  

 

Wow.  So on my Music Hall with the I think like a DC synch 4 watt motor I can do a 90 kg platter.   That's a lot of 4 oz fishing weights I have to glue on. I better get going to the bait and tackle store to improve my stereo. 

@mijostyn The belt is brand new. Just put it on about a month ago. The old belt had stretched. The measurements I reported using the RPM app were done with the new belt.

 I was shocked by the poorer performance of the WOW. Acoustic Signature does not publish specs for speed stability, wow, flutter and rumble.

Seems that AS relies on the marketing of their special spindle material, the huge platter and the brass inserts to impress buyers. Must be good performance with all those buzz words, right. A simple measurement shows the difficulty of relying on bling rather than real measured performance. I was fooled. I bought it. One of my biggest audio gear mistakes. Won't happen again.

I believe in these RPM apps!  Perhaps that is because my 42 year old direct drive Denon DP-30L measured so well. Spot on RPM and decent wow. Thanks for the tip!

@brev Yah, it is fun making these measurements. I wish that the developer would publish his/her methodology. For example, what algorithm is used for the WOW calculation? Is it one of the standards?

I don't think we'll find out any time soon. Apps are usually closely guarded secrets.

But he/she could indicate which standard he/she is following, if any. Without this knowledge, it is impossible to compare RPM results to manufacturers' published performance.But relative performance between tables is valid.

Dear @kevemaher  : As you I bougth my units at blind on specs and were ( two units ) coming from an audiophile that I respect, so second hand at very good price: 2 top of the line ( in those times. ) TTs with 3 outboard motors and one motyor controler that I had to modify to choose between one TT or the other and till today I have not a single issue with those AS and the " belts " I use are simple silk thread amnd yes I have to push-start. In reality a critical issue with my model TTs was that came with no kind of damping footers so what I did it is to put 3 AT-616 pneumatic Audio Technica footers and a top these footers goes a centered an inverted aluminum tip-toes that for me makes very good job.

 

Here you can read some real time measurements in one of AS today model:

 

https://www.acoustic-signature.com/files/downloads/tests/2021-08-stereoplay-double-x-neo-ta-500-neo-mcx1-en.pdf

 

R.

@rauliruegas Hi, Thanks for the link. Surprisingly, the wow and flutter reported for the Double X by the author of the article you referenced is the same as the wow value I reported above for the AS WOW XXL using the RPM app. This result is encouraging, but not enough for me to trust completely, because the method of analyzing the data may be different.

There is no denying that the Double X measured wow value is 5x higher than the 0.02% I measured for the DP-57L table using the RPM app. Even more damning, the Double X it is worse than the wow reported for the Micro Seiki DD-40, an "entry level"  turntable.

The rumble spectrum is also quite informative. Although I can't make a 1:1 comparison with my (unpublished) results because gain and reference voltages may differ, I can say that the rise in noise from the 500 Hz baseline to the peak at 10Hz is about 60 dB for the Double X table in the article. I'm using the blue curve. This may be an incorrect trace, but there is no legend to indicate what the conditions were for each curve. My results indicate only a 30 dB rise for the DD-40. This is a 30 dB (30X) difference!!! Perhaps the region around the Double X was particularly high in vibration on the day of measurement. Or the line filtering in the Double X power supply is poor design or faulty.

One can also see the on the same chart a 50ish Hz peak.frequency. It rises 60dB above the baseline. The source is not identified, but is probably the AC line frequency. My measurements used a rumble track on the Hi-Fi News test record. The AC peak for the DD-40 is not visible, buried in the noise, which is already lower than the Double X.

It is very obvious now why Acoustic Signature does not publish these specifications. It could be very difficult to explain why a 70s "entry level" table beats their Double X for wow, flutter and rumble.

With all this now under our belt, can one say which table sounds better?

No.

But if one had to pick a table based on these results, the choice is clear.

I am also boggled to read that the reviewer summarized that the Double X performance as "high end".

How low do wow, flutter, and rumble have to be before they become inaudible in a "typical" listening situation? If the value is higher than that of every measurement result shown here, then the better performance of the DD-40 and DP-57L is not really needed. The Double X performance will be indistinguishable from those tables. But I think the answer is that since the manufacturer cannot control the conditions that a buyer will use its product, the manufacturer must strive to equal or beat the performance of the other "high end" tables.

If none of those publish these specs either, then my entire discussion is meaningless, since there's no way to determine from measurements which table is "better". Listening is always a very good method, but is usually highly compromised in any showroom environment. Perhaps listing is the only spec to test for. But how many people purchase a table without extensive listening to it prior to that purchase? I'd wager most do.

@kevemaher  

With all due respect, keve, I think that you are putting the cart before the horse. Before one aggregates observations, one must make observations. The difficulty with making speed observations is that for practical purposes they must be averages: distance travelled divided by elapsed time. This is not an instantaneous quantity.

Even aggregating a finite number of observations implies discrete, not continuous. That means sampling frequency.

This is not a moot point because modern controllers tend to correct speed at about 10KHz. If it were easy, they would correct more frequently. I doubt that an app is better; in any case, it's important to quantify the limitations of the observations; in this case the granularity  imposed by sampling frequency.

Then one could aggregate the data into moments, from which the central moments of mean, standard deviation, skewness, kurtosis, etc. could be calculated, although perhaps a spectral or Fourier analysis would be more revealing.

There is no problem with the data arising from a process which is not perfectly random - it is data. The point at which randomness enters the picture is in identifying which inferences are valid, and which are not.

Yes, I think that speed stability is a problem. The question then is, "Which frequency?" I strongly suspect that most of the audible differences between turntables arise from small speed variations in the lower kilohertz range, which we hear as  brilliance or sibilance. It is obvious to suspect speed instability of causing this - but at greater frequencies than are usually measured. For example, bearing noise affecting speed.

By way of evidence, a common criticism of Nottingham turntables (high mass, low torque) is that they are 'dark', that is, without brilliance. I prefer the term 'smooth'. Also, that is how the bearing noise from my 1.8W motor manifests itself. Yes, it's repeatable.

As you point out, "Measuring performance parameters of instruments is crucial to product development." But unfortunately, associating numbers to phenomena is one of the most difficult human activities - doing it right, that is. It is therefore of cardinal importance to report the limitations of the measurement before reporting the results of the analysis. In my opinion.

@terry9 There is a well-defined method for measuring wow and flutter and rumble, which only differ in frequency and source, but not in nature. This method turns out to be quite complicated. Whether the RPM app developer used this method or not is not disclosed. This makes comparison between published results and the RPM app results dubious. I do think that comparisons between tables using the same app (and phone) are valid qualitatively. That's why I feel sanguine about the comparisons I've made and reported.

If a manufacturer clearly states the method used (there are standards), then it can be used as a valid comparison between this table an others measured using the same method. It happened that I did measure the same wow 2 sigma as the spec sheet for the DP-57L and the DD-40. This may be coincidence. If a manufacturer does not provide a spec based on a standard protocol, then no valid conclusion can be made, obviously.

I find it difficult to believe that a manufacturer would not measure their product according to the well-accepted protocol. Engineering must have used some quantifiable method to characterize their creation. Engineers need a goal to reach. They need a goal that tells them that they've reached the goal and can freeze the design, stop development and move on to the next problem.Sales and marketing can decline to publish the results for a variety of reasons. Whatever the reasons, I feel a bit queasy without reported specs. I made this mistake with the WOW XXL. I will never do it again.

The test only goes to 200Hz. Any software and hardware (computer with A/D if chosen to do digitally) will have plenty of bandwidth (sample rate) to provide accurate results. The actual test uses a different frequency (3kHz or 3.15kHz), This frequency is detected, not speed. This makes the measurement more accurate because integration (averaging) times can be very short.

Implementation of the standardized protocol with all due attention to the accuracy of the test gear can accurately reproduce kHz frequencies. But only the errors that show up below 200Hz will be used to develop the result. If your hypothesis is correct, there is no method known today to capture errors from frequencies higher than 200Hz.The spec would have to change.

I have been in Engineering my entire career developing products for medical research, defense and communication at the highest level. What I've stated above is a part of how the development process works. Specs are designed so that they are measurable. If it is found that a method does not capture all the errors known, then the spec method is changed. Development cannot proceed without a measurable goal. In fact, turntable engineers may have an in-house spec to reach, knowing that meeting the in-house spec will guarantee that the industry standard method will produce the desired performance.

I don't presume to be an expert in measurement methods for characterizing turntables. I'm learning. Meanwhile, I call on my work patterns to inform me how I would proceed if developing a table. Differences in my approach to turntable engineers approaches may differ in details, but are the same in nature.

I do agree that some things are difficult to quantify. Turntable performance is not one of them. Whether one prefers this or that table is an emotional decision, a valid concern.Wow, flutter, and rumble measurements are quantifiable and repeatable (and agreed on).

@kevemaher I agree that wow, flutter, and rumble measurements are quantifiable and repeatable and agreed upon. I think, however, that this is not the whole story and that a 50KHz sampling rate would give us the data needed for a more robust analysis.

Thanks for the discussion, @kevemaher .

@kevemaher 

I was never an AS fan. I do not care for units that go out of their way to look flashy without obvious benefit. Having said that there are four sources of noise when playing vinyl, the turntable, the record, the environment and lastly electronic. I assume you used the same record for all measurements. The environment is basically the same for each table and to my knowledge none of them have isolating suspensions. Electric noise would also be the same for each table. The conclusion you came to is correct. The AS has a Rumble issue. Rumble is a problem if you can hear it or if it affects the performance of speakers particularly subwoofers. I also think it is a significant marker of overall quality. It is also possible this turntable was damaged.

I had an 80s era MS turntable which was wonderful. Its only failure was lack of a suspension. The apartment building I lived in had the worst environmental rumble problem I have ever lived in. The AC compressors were clearly audible in spite of concrete floors, all 19 stories. Because of this I returned to the Linn LP12 which was much quieter as long as you tip - toed around it.

Measuring is always the best way to confirm anything. You also discover that “ears” have limited sensitivity when dealing with certain things as it sounds you only identified the problem by measuring.  Measuring is also a great way to train your ears. If you really want to have fun get yourself a Dayton Omnimic V2. They are about $300 and worth every cent. You need a PC. The program is free but you need to have a serial # to access it. In the process you download the calibration file for your microphone. You will find it essential for possitioning loudspeakers, adjusting room treatments and writing target curves if you ever get into digital signal processing.

Speaking of environmental noise coming through. What about using those rare earth magnets to levitate the turntable.  Maybe use rubber bands to keep it in place.  I just might try it.  Sounds like a fun experiment.  

@mijostyn I use REW for room characterization. It is freeware. The functions appear similar.

Dear @kevemaher  :  As you said almost no manufacturer disclose the the whole measurements process they used including the different standards they used.

Here some examples:

 

http://www.thevintageknob.org/technics-SP-10MK3.html

 

http://www.thevintageknob.org/denon-DP-100M.html

On specs this Denon TT is the only that shows Measured spec on speed fluctuations: 0.06%

http://www.thevintageknob.org/micro_seiki-DD-100.html

 

http://www.thevintageknob.org/yamaha-GT-2000.html

 

http://www.thevintageknob.org/sony-TTS-8000.html

 

http://www.thevintageknob.org/sony-TTS-8000.html

 

http://www.thevintageknob.org/garrard-401.html

 

Your AS 60db is prety " decent " for a BD design and is really close to the DD MS unit. Btw, @mijostyn  my vintage AS TTs never showed that rumble you mentioned is reflected in the subs not only that I do not noted by " eyes " but neither with my fingers against the Denon DP 80 and the Technics SP 10MK2.

I think that the OP really puts the " finger " where it hurts when posted:

 

"" How low do wow, flutter, and rumble have to be before they become inaudible in a "typical" listening situation? ""

 

That is in true the real issue for us MUSIC lovers and audiophiles and for what I know I think that no one measured till today with the same standards/process.

 

I remember that in cartridges the separation spec that normally is measured over the frequency range but manufacturers only gives the measure at 1khz and main reason ( I think all we know it. ) is that at both/near frequency ranges the " figure is way lower over the " figure " showed by the manufacturer that today I think no one gives as in the past when the cartridges came with athe measured diagram of frequency response and separation from 20hz to 20khz and with the test record used, at what temperature, VTF and the like and speed velocity of the diagram.

In those " gold " times audiophiles were way better infortmed to decide what to buy and in those times and talking of cartridge separation specs with severaltests and measures was accepted that the minum separation spec must be 20db with no " difference " if that figure goes to 30db because separation is not linear/flat.

Lyra Atlas Lambda SL shows 35db on that spec but Allaerts Formula 1 is 70db at 100hz and 20khz and " only " 60db at 1khz but neither manufacturer disclose the measurement process about.

 

R.

 

 

Dear @kevemaher @terry9  and friends  : This is a learning TT reviews for measurements that came from 1985:

 

Audio-1985-02.pdf (worldradiohistory.com)    page 58.

 

and this another one:

 

Audio-1985-04.pdf (worldradiohistory.com)  page 62.

 

R.

 

@terry9 Thank you very much! And thank you for joining in. I'm having fun learning how other real users think about audio and audio gear. I can't get that here in this countryside location.

Thanks to everyone else also.

@rauliruegas Thanks for the links. Great reading material. Seems like companies use whatever measurement protocol they feel is appropriate. This is very similar to the "alphabet soup" of specs that exist in the Optics and Electronics engineering world.

 

I thought about starting a new thread, but the conversation on this one is a good intro into my next question.

 

"How does one choose between belt drive (including string, fishing line etc...), direct drive and idler drive?"

 

There seems to be two crowds, direct drive vs all the others. I've had both. I had a bad experience with the AS table, but that could be an isolated problem. I really don't have a preference.

Very curious to hear ideas!

@kevemaher  : In this forum there are 5-6 threads dedicated to your same question and the issue is not exactly the drive TT design because the kind of drive is only one TT characteristic and yes very important but there are other very important characteristics too like: platter build material or blend materials well damped, well dampend isolated arm board, excellent damped suspension, silent bearing, tec, etc,.

At the end no matters the drive design the TT must be inert with out any kind of " sound " by it self . It has to be speed accurated and with good speed stability. 

I that scnario any of those 3 drive designs can make the job. Design , materials and quality level excecution is more or less the name of the game.

 

Please do a fast search in Agon forum to find out those TT threads.

 

R.

Dear @mijostyn  : This is the one for you and  for the OP because this is not DD but BD design:

 

Audio-1986-06.pdf (worldradiohistory.com)  page 98.

 

R.

Dear @kevemaher  : Do you want to know what other audiophiles think on turntable different Drive Designs?

Well in at least 2 of the 5+ analog threads this gentleman: @mikelavigne  participated and he owns those 3 today top TT's you ask about. This gentleman builded his home system through many years and I know that first than all he is a MUSIC lover.

Before the TT's he owns today he owned at least other 2 top TT's in those learning years: the Goldmund Reference and latter on the Rockport Sirius 3. I followed his audio history for to many years and here his today system:

 

Mike Lavigne's System | Virtual Listening Room (audiogon.com)

 

R.

@rauliruegas 

I read that review back in the day and It's positivity over vacuum clamping remained lodged in my neurons. The comments about the turntable sounding "dull" only for everyone to decide that the reference system was too bright is a characteristic that is legion in high fidelity systems. There is a tendency for us to prefer brighter reproduction, brighter is better. There are many problems that will cause high frequency aberrations. In this review it is the high frequency resonance of underdamped records. But this problem also occurs with digital sources.  It manifests itself as sibilance and poor imaging. Sibilance is obvious but the effect on imaging is more insidious. I "look" for it by listening to cymbals. The entire frequency palate should emanate directly from the cymbal. The cymbal should be in focus. Instead the cymbal will have a glow of high frequency. At its worst you can not define the cymbal at all. It is smeared across the stage. The usual cause of this is poor room control with omnidirectional loudspeakers. With a system that seems to sound dull listen carefully to the cymbals. If the cymbal is sharply defined and all the high frequencies are present and sibilance is totally absent you listening to an accurate system in a well managed room.....with vacuum clamping:-)