MM vs MI vs MC

[USER]

For comparison:

View attachment 125667

That dip at around 5200Hz seems to be in all the CBS records then.

I just measured it again with my second CBS record:

Every record has its issues. Here a dip past 14kHz. I should measure the SAS/S again to see how similarly it affected. Still, these measurements are consistent in telling a good story.


A question: do you know why your 2nd and 3rd harmonic lines go past 10k and mine don't? Is it related to a scaling setting?

Also, how did you get the margin of error figure on yours? That's cool.

 

[JP]

That's a @scott wurcer question.

The +/- is a tweak I did. It's basically the delta/2. I want make it find the median and do a true +/- from that, or minimally from 0. If I do that I'll add it to the script that is distributed.

 

[eliash]

That dip at around 5100Hz seems to be in all the CBS records then.

I just measured it again with my second CBS record:

View attachment 125670
Every record has its issues. Here a dip past 14kHz. I should measure the SAS/S again to see how it is affected. Still, these measurements are consistent in telling a good story.


A question: do you know why your 2nd and 3rd harmonic lines go past 10k and mine don't? Is it related to a scaling setting?

Also, how did you get the margin of error figure on yours? That's cool.

Regarding the HF dip, already the late 1960s dhfi2 test record manual stated: Above 14KHz, resonances between record mass (!), effective stylus mass and cart compliance are possible...when measuring the Nagaoka MP-500 (#475), a similar dip is visible around 16KHZ...eventually the record pressings come from different sources...

...eventually try with a record clamp or weight and check for differences.
For example, my SME TT´s record clamp has a significant impact on external induced mechanical noise (e.g. knocking on various parts of the TT and self resonance from the speakers at high volume level, though at low frequencies)

 

[scott wurcer]

That's a @scott wurcer question.

This issue is due to harmonics that exceed fs/2 being excluded. If you sample a 20KHz sweep at 96kHz the plots will extend to 48kHz so the seconds should fully extend and the thirds should go out to 16kHz. If you submit a 44.1kHz file you see the plots you have.

EDIT - Note that the harmonics are displayed below their respective fundamentals, this is the only thing that made sense to me so the frequency axis is only for the fundamental which I think is standard for this kind of plot.

 

[scott wurcer]

Regarding the HF dip, already the late 1960s dhfi2 test record manual stated: Above 14KHz, resonances between record mass (!), effective stylus mass and cart compliance are possible...when measuring the Nagaoka MP-500 (#475), a similar dip is visible around 16KHZ...eventually the record pressings come from different sources...

Spinning test LP's at 1/10 speed will reveal many evils (at least they move down into the audible region). Even doing 33/45 on the same test track helps to separate LP vs tone arm/cart issues.

 

[JP]

Yes I do the same for square waves to differentiate the cutter ringing from playback.

 

[scott wurcer]

Yes I do the same for square waves to differentiate the cutter ringing from playback.

Folks should also realize the CBS Labs disks were made with GR and B&K generators with chain drives connected to chart recorders. Notice the "start your engines" instructions on some of them. The sweep oscillators in most cases had to switch ranges to go the full 10 octaves (hence some glitches). These were never intended for scrutiny at this resolution.

 

[Helicopter]

I wonder what kind of ASR test record we could produce with a budget of $2-3k for fixed costs plus whatever for the actual records.

I am thinking RIAA and non RIAA sweeps, pink noise, etc. We wouldn't need any of the stuff you use for setup, and wouldn't need torture tests, since there is nothing wrong with the tracks for those purposes on existing records.

 

[JP]

Almost no one will take that job on.

 

[Helicopter]

Too bad the $20 custom lathe cut records only go to like 5kHz, and probably badly where they do go.

 

[JP]

I work with a number of mastering/cutting engineers. I’ve found exactly one who was willing to take a look at the project. Even at that I think there’s a high likelihood he changes his mind once he gets in to the weeds. This is a project you do because of passion - no way it makes any business sense.

 

[scott wurcer]

I am thinking RIAA and non RIAA sweeps, pink noise, etc. We wouldn't need any of the stuff you use for setup, and wouldn't need torture tests, since there is nothing wrong with the tracks for those purposes on existing records.

We've been there, this subject is good for threads that span years. BTW the CH 7"/45 test LP is about as good as it gets albeit limited tracks. Their pink noise is as accurate as any I have seen.

 

[JP]

CH 7"/45 test LP

Which one is that?

 

[scott wurcer]

Which one is that?

CH Precision in Switzerland gave one out with their $30,000 pre-amp. Jan got me one, not sure they are still available.

 

[JP]

Oh right I remember now. Looked for it back then and couldn't find one. I don't think I know Jan well enough to ask that favor.

 

[scott wurcer]

Oh right I remember now. Looked for it back then and couldn't find one. I don't think I know Jan well enough to ask that favor.

PM me I'll send it to you.

 

[eliash]

Yes I do the same for square waves to differentiate the cutter ringing from playback.

That´s interesting,
when you detected some cutter ringing, was it long enough to get an idea about its frequency?

 

[USER]

In case anyone is interested in me following up on my Clearaudio Concept turntable and its failing W&F measurements by Miller Audio research, I purchased the Tacet Vinyl: Check test LP and made some recordings. @JPJ was very kind to run the recordings through his scripts and these are the results. Again: thank you!

A couple of thoughts:
1. The Tacet disc is off center and quite wobbly. I DO NOT recommend it.
2. Regardless, the measurements are much better and closer to spec than what M.A.R. found, despite the issues brought upon by the record itself. That's really all I can say without another test record. While nothing extraordinary here, this comes as a relief! So whatever issue they found was either limited to their test turntable or has been corrected in the years since.

 

[MakeMineVinyl]

I have found that generally its pretty hard for any good turntable to have enough wow or flutter to be audibly distracting. Tape is another matter, and a lot of older analog tape masters have obvious wow and / or flutter.

 

[eliash]

In case anyone is interested in me following up on my Clearaudio Concept turntable and its failing W&F measurements by Miller Audio research, I purchased the Tacet Vinyl: Check test LP and made some recordings. @JPJ was very kind to run the recordings through his scripts and these are the results. Again: thank you!

View attachment 129917
View attachment 129918
A couple of thoughts:
1. The Tacet disc is off center and quite wobbly. I DO NOT recommend it.
2. Regardless, the measurements are much better and closer to spec than what M.A.R. found, despite the issues brought upon by the record itself. That's really all I can say without another test record. While nothing extraordinary here, this comes as a relief! So whatever issue they found was either limited to their test turntable or has been corrected in the years since.

Quite interesting, looks like the Clearaudio is a belt drive as well. In the waveform diagram one can see a beating (superposition) of the record and the belt influences at 6s, when the beating is minimum (both cancel each other) and later around 18s looks like the maximum (both add up). It looks similar to my SME, but with higher beating frequency, so the belt loop seems to be larger (belt longer) as in my case. Anyway, almost full cancellation means both effects do have the same magnitude...and also no worry...