You are here

Log in or register to post comments
hollowman's picture
Last seen: 1 month 3 weeks ago
Joined: May 28 2009 - 12:59pm
16/44.1 digital recording (on vinyl): source of ultrasonics

Watch the following YouTube video (it's about spectral analysis of the 1985 digitally-recorded Beach Boys album, which was released on vinyl):

The vlogger concluded that post-22khz content is "inaccuracies in vinyl" or "cartridge mis-tracking".
But I'm not sure I buy that. For one, he did not repeat the experiment with another turntable/cart. Or he didn't attempt to re-align the cart. Etc. ,etc.

What could be some reasons for the post-22k ultrasonic content shown in the video?

If anyone has ripped a digitally-recorded LP (e.g., 1980s vintage Telarc, etc) to at least 24/96k, and has Adobe Audition (or similar) music-analysis software on their PC, you can repeat YouTube vlogger's experiment. ( I would do the experiment myself, but my analog rig is in storage on the other side of the country!)


JA, in his RMAF 2018 talk ( ) reported ripping LPs with an Ayre QA-9 and Pure Vinyl. Hint, hint, wink, wink, JA!!

It's possible that beyond-22k energy (noted by vlogger) is generated by cart./stylus.
Perhaps as Peter Lederman (Soundsmith) discussed in his 2018 RMAF seminar:
(i.e., mass of stylus, moving magnet (or MC), dumps energy back to diamond tip/groove interface). And the above-22khz energy content is (are) harmonics of the music signal.

JA noted ultrasonic content of ripped LPs (e.g, Obie Clayton) in his Oct. 2000 article "What's Going on Up There?"
Similarly, Dr. Rob Robinson (Channel D) noted ultrasonics beyond 90k in LPs he ripped:

Also see Robinson's myriad RMAF "Vinyl Ripping" seminars for "live" demo of spectrogram. E.g.,:

In Dr. Robinson's 2015 RMAF seminar ...
(at time 16:30), he does note that cutter head maxes out at ~50khz. But ... he further explains that that is only a mechanical limitation. But LP still shows content out to beyond 90k!!

hollowman's picture
Last seen: 1 month 3 weeks ago
Joined: May 28 2009 - 12:59pm
Any takers on this experiment ... JA???

Unfortunately, my analog rig is over 2k miles away, boxed up.
Otherwise, I'd repeat the experiment in the OP.

What you need:

** A lossless ripped file (wav, flac, etc.) of an LP album that was recorded digitally (e.g., Telarc, etc.). The rip should've been at least 24-bit/96k. Preferably, 24/192.

** A computer with installed software like CoolEdit or Adobe Audition.


Analyze the file in software. You can use a smartphone to capture a video of your results. It's important that results be captured on video to get a "dynamic assessment".

Since I know JA has conducted experiments like this a few times in the past (see OP), I am suggesting he do the experiment and post it on the Stereophile site (and YT channel)
;-) !!!!

If we get that far ... perhaps we can analyze the output of open-reel decks. But that's a project for the future.

jgossman's picture
Last seen: 4 months 1 week ago
Joined: Aug 18 2011 - 6:21am
Stylus Resonance

I'm completely agnostic on the proposition because since my 35th birthday or there-about I have absolutely 0 hearing above 17 KHz and very little at 15KHz. There is, in fact very little musical information past 7KHz anyway. Instruments just don't play that high. However there ARE harmonics in many analog recordings well into ultrasonics and I'm not convinced they don't affect the playback of LP's. Because of this, I'm inclined to believe (as in I don't KNOW these things) 2 things. At 33/45 RPM right up until the middle or so of a 33 RPM side and full through a 45 RPM side, an LP contains all the INFORMATION needed for superior playback well into ultrasonic harmonics, discounting for misaligned cartridges, excessive low frequency "bounce" (read suspended, over damped plinths), bearing chatter in the arm, etc, etc. The reason I say all this is that the implication of the OP is that digital is showing off a shortcoming of the analog format - when it's possibly showing off a shortcoming of digital recording artifacts OR as I suggest in my Subject a stylus being underdamped by too low a tracking force OR a worn rubber suspension grommet in the cartridge (gummy-muffin, if it's an Ortofon). It seems sort of a silly thing to worry about, IMO.

commsysman's picture
Last seen: 9 months 3 weeks ago
Joined: Apr 4 2006 - 11:33am

One common source of ultrasonic oscillation is a poor gound connection where an RCA cable does
not fit tight enough on the jack it is connected to.

Check for tight fit on the outer part of the connector and try switching cables in some places.

  • X