Turntable Speed Precision

[TBone]

Wow, today's technology ... do we really need an apt to hear timing issues?

Making a perfect Turntables / drive system is a compromised affair; belters have long been scrutinized for their "inherited" timing issues, conversely the so-called DD advantage has always been "superior" timing ... that ... despite the fact that many DD turntables I've witnessed reproduce a piano as if it required tuning.

To my ears, "measuring" proper timing is as easy as comparing better digital to better vinyl. When I listen to an excellent analog based system, with any drive, timing issues have rarely become the sonic showstopper that others often suggest.

tb1

 

[Bill Hart]

Do not, under any circumstances, listen to the Speaker's Corner reissue of 'Can't Buy a Thrill.' On 'Fire in the Hole,' the tape slips and you think your TT has gone haywire. Sort of a well-known novelty. I forgot about it when I listened to it last week and freaked.

 

[TBone]

Do not, under any circumstances, listen to the Speaker's Corner reissue of 'Can't Buy a Thrill.' On 'Fire in the Hole,' the tape slips and you think your TT has gone haywire. Sort of a well-known novelty. I forgot about it when I listened to it last week and freaked.

Funny, in my travels, Steely Dan has often been used to demo the advantages of DD.

tb1

 

[catastrofe]

I did not see your question until today. I will try to be more specific.

All measurements should be made in the same conditions to eliminate outside variable influence. If they are not, one must use a validated test method that quantifies and accounts for those factors. If you do not, the tool is a nice estimator of performance, but really doesn't mean much, especially when measuring at the low end of its sensitivity.

To demonstrate this, simply have your Apple device play the program's test tone from its own speakers and record that. You will see that the recorded wave form is pretty messy and not at all one frequency. In fact, the level of variation is exactly what the best turntables produce themselves. We know that the DAC that drives the apple speaker is doing the best it can to command exactly 3150Hz, but in fact, the mic is measuring something on the same scale as good turn tables put out. Thus, if you believe you have a measurement that is in this range take it with a serious grain of salt since the apple hardware/software's own accuracy is at its measurement limits of a good turntable's output with a tone record. See the attached pictures of a representative recording.

The Platterspeed app is great to make sure your system, as quantified by your phone/iPad, is not changing or for comparing two side by side turntables, in identical conditions. Be careful beyond that when making calls about superiority when the measurement is at the same scale as the iPad's measurement of its own 3150Hz test tone.

Jonathan,

Respectfully, I believe you're incorrect regarding your iPhone example. The test tone in the application is a recording of a 3150hz test track (from an album), not a signal generator. It therefore contains any variation associated with the vinyl or the turntable used to record the track. There's a message to this effect in the popup that opens when you launch the test tone. That's why you see variability using the internal tone. . .it's not an indicator of the variability of the testing mechanism.

So the question remains in my mind, why this method is more or less accurate than a stobe/disc, or say, the Kuzma Strobi.

Best,

Bob

 

[Bill Hart]

Jonathan,

Respectfully, I believe you're incorrect regarding your iPhone example. The test tone in the application is a recording of a 3150hz test track (from an album), not a signal generator. It therefore contains any variation associated with the vinyl or the turntable used to record the track. There's a message to this effect in the popup that opens when you launch the test tone. That's why you see variability using the internal tone. . .it's not an indicator of the variability of the testing mechanism.

So the question remains in my mind, why this method is more or less accurate than a stobe/disc, or say, the Kuzma Strobi.

Best,

Bob

Bob, if I understood Jonathan's point (and perhaps I didn't), it was that the app showed variability even using the iPad's own test tone.

 

[catastrofe]

Bob, if I understood Jonathan's point (and perhaps I didn't), it was that the app showed variability even using the iPad's own test tone.

But his example is flawed, because the test tone in the app is not a pure 3150hz tone, it's recorded from an album track. Since it's recorded from an album, it includes whatever anomalies are being introduced by the playback system.

If the tone was from a signal generator, he would be correct.

 

[Bill Hart]

But his example is flawed, because the test tone in the app is not a pure 3150hz tone, it's recorded from an album track. Since it's recorded from an album, it includes whatever anomalies are being introduced by the playback system.

If the tone was from a signal generator, he would be correct.

Gotcha- now re-reading you post, you made that clear.

 

[garylkoh]

That's right. When you tap the button to play the test tone, a pop up says

"This demo starts playback of a recorded real 3150Hz track. It automatically stops after 30 seconds........ Note: the fluctuation is due to wow and flutter of the real turntable."

Measuring the test tone from the app gives you a picture of the turntable that Dr Feickert recorded the 3150Hz tone off. When measuring the tone from a signal generator, it gives me an absolutely flat plot with no variation off the 3150Hz centerline..... unless you're swinging the phone around.

I'm using an Android phone to do this measurement.

 

[Johnny Vinyl]

I'm using an Android phone to do this measurement.

What APP are you using Gary? I thought Platter Speed (?) was an iPhone add only.

 

[Soundproof]

Do not, under any circumstances, listen to the Speaker's Corner reissue of 'Can't Buy a Thrill.' On 'Fire in the Hole,' the tape slips and you think your TT has gone haywire. Sort of a well-known novelty. I forgot about it when I listened to it last week and freaked.

I freaked when I heard that the first time. How did that get through so-called quality control?

 

[garylkoh]

What APP are you using Gary? I thought Platter Speed (?) was an iPhone add only.

Nope, Platter Speed also works on Android.

On Android, it even has a DIN IEC 386 function - measures wow on a turntable (I guess so that you can tell if your turntable is up to spec).

I find it interesting, as even different treatments on the belt of my Roksan affect speed stability.

 

[Johnny Vinyl]

Nope, Platter Speed also works on Android.

On Android, it even has a DIN IEC 386 function - measures wow on a turntable (I guess so that you can tell if your turntable is up to spec).

I find it interesting, as even different treatments on the belt of my Roksan affect speed stability.

Found the dev site and am installing it now.

Very weird though.... when I typed it into the Play store it came up empty. Oh well.

EDIT: I guess I better buy a Test record that has that 3150Hz tone. Duh!

 

[garylkoh]

Found the dev site and am installing it now.

Very weird though.... when I typed it into the Play store it came up empty. Oh well.

EDIT: I guess I better buy a Test record that has that 3150Hz tone. Duh!

You don't already have this??
http://www.needledoctor.com/Ultimate-Analogue-Test-LP

 

[Johnny Vinyl]

You don't already have this??
http://www.needledoctor.com/Ultimate-Analogue-Test-LP

So many of those around that I never knew which one to buy. I'll get it now though! Thx!

 

[garylkoh]

The Ultimate Analogue has the 3150Hz track.

This is the one I use most often, but that doesn't have the necessary 3150Hz tone for Platterspeed: http://www.musicdirect.com/p-7165-hifi-news-test-lp-producers-cut.aspx

Dr Feikert makes one that works with the free Platterspeed app: http://shop.adjustplus.biz/product_info.php?cPath=22&products_id=45