Strobe disc for 432 hz tuning?

innuendo1231

innuendo1231

New Member
Hello Community!
A fairly controversial topic I know, but let's forget about that part for now.
I like to tune all the music listen to to 432 hz. In the digital world I achieve that by either playing them back at 98,18% speed (not using pitch changers, as that's a very lossy algorithm) or by *setting* their sampling rate to 43298 and then resample them to 44100 with izotope src.

So I thought I should try to tune a turntable to this kinda thing too.
One concern was the imperfect RIAA equalization. To hear how bad it would be, I played around in a sound editor and a RIAA vst plugin. I took a song and edited it in two different ways for comparison:

1.) Apply riaa -> apply inverze riaa -> set sanpling rate to 43298 -> resample to 44100.

2.) Apply riaa -> set sampling rate to 43298 -> resample to 44100 -> apply inverze riaa.

I have to say that I heard no audible difference between the two in terms of equalization, listening with a sennheiser hd555 headphone.
I suppose offsetting the spectrum by 8 hz doesn't hurt the riaa process much.


What I couldn't find is a way to create a custom strobe disc that is aiming for this kind of tuning.
The rpm should be 32.72727..... instead of 33.3333......
 
Register to hide this ad
Well, where are you located? Because in a 50 Hz country you'd need to live with a little deviation, as the custom strobe disc would theoretically have to sport 183 1/3 marks (instead of 180), while in a 60 Hz country your custom disc would need 220 marks (instead of 216).

Greetings from Munich!

Manfred / lini

P.S.: The 50 Hz disc with 183 marks would put the standard pitch at not quite 432.8 Hz (provided I've calculated correctly...).
 
Last edited:
Tom: Oh, I'm not aware I actually told, how I've arrived at the numbers of marks mentioned above. But anyone, who had a bit of junior high school maths, should be able to figure that out anyway, I'd hope... Might just take a while, though, due to the lack of practice. That's why I generally prefer to still calculate at least some stuff myself (instead of using convenient online calculators...), so I don't lose practice completely. What I've already forgotten seems bad enough...

Greetings from Munich!

Manfred / lini
 
innuendo1231 said:
Hello Community!
A fairly controversial topic I know, but let's forget about that part for now.
I like to tune all the music listen to to 432 hz. In the digital world I achieve that by either playing them back at 98,18% speed (not using pitch changers, as that's a very lossy algorithm) or by *setting* their sampling rate to 43298 and then resample them to 44100 with izotope src.

So I thought I should try to tune a turntable to this kinda thing too.
One concern was the imperfect RIAA equalization. To hear how bad it would be, I played around in a sound editor and a RIAA vst plugin. I took a song and edited it in two different ways for comparison:

1.) Apply riaa -> apply inverze riaa -> set sanpling rate to 43298 -> resample to 44100.

2.) Apply riaa -> set sampling rate to 43298 -> resample to 44100 -> apply inverze riaa.

I have to say that I heard no audible difference between the two in terms of equalization, listening with a sennheiser hd555 headphone.
I suppose offsetting the spectrum by 8 hz doesn't hurt the riaa process much.


What I couldn't find is a way to create a custom strobe disc that is aiming for this kind of tuning.
The rpm should be 32.72727..... instead of 33.3333......
Click to expand...
The difference between doing this in the digital domain and analogue is that digitally one can change the pitch but retain the tempo. The same pitch change done in analogue will slow the tempo intolerably - well at least to me!
 
Wayner: There's a certain debate about which should be the correct standard pitch. Apparently the OP prefers 432 instead of 440 Hz and would like to tune his turntable accordingly, which is why he'd need one with a custom number of marks.

Greetings from Munich!

Manfred / lini

P.S.: Personally I wouldn't do that, 'cause not every orchestra sticks to the regular standard pitch of 440 Hz, so one would first have to determine the actual pitch, before one could really precisely aim for 432, if one actually would like to...
 
Why not get a non contact laser tach and read the rpm's directly from the platter?
They're inexpensive.
 
lini said:
Wayner: There's a certain debate about which should be the correct standard pitch. Apparently the OP prefers 432 instead of 440 Hz and would like to tune his turntable accordingly, which is why he'd need one with a custom number of marks.

Greetings from Munich!

Manfred / lini

P.S.: Personally I wouldn't do that, 'cause not every orchestra sticks to the regular standard pitch of 440 Hz, so one would first have to determine the actual pitch, before one could really precisely aim for 432, if one actually would like to...
Click to expand...

Ok, I'm still stupid. So he wants the table to run slower? If the record was cut at 33 1/3rpm, why would I (or anyone else) care about 432hz. The end game is the pitch of the music recorded, and many old records are more then likely off pitch as they did not have the technologies as they do today. It also doesn't consider the drag caused by a stylus in the groove, which could be significant with lower torque motors.....
 
Heyraz: Hm, the tachometer seems like a good idea. I'll look a used one up.

Fiddlefye: I don't think 1.82 % of tempo change is that much audible. The artefacts that speed-retaining pitch modifiers introduce are very much audible on the other hand. All they do is succesively delete small frictions or put in small iterpolated "spacers" to change the tempo.
 
innuendo1231 said:
Heyraz: Hm, the tachometer seems like a good idea. I'll look a used one up.

Fiddlefye: I don't think 1.82 % of tempo change is that much audible. The artefacts that speed-retaining pitch modifiers introduce are very much audible on the other hand. All they do is succesively delete small frictions or put in small iterpolated "spacers" to change the tempo.
Click to expand...

Tempo change means pitch change and I suspect there are musicians that will be able to tell when something is out of tune.
 
You can't just turn the turntable speed know until it sound right to your ear? I suspect you don't have a frequency counter, but for ten dollars a musical instrument tuners can be set that low. You don't have an LP with A tuning note?

Otherwise just print out the correct strobe pattern on a piece of paper.
Screen Shot 2019-02-04 at 8.38.09 AM.png
 
Last edited:
WaynerN said:
Tempo change means pitch change and I suspect there are musicians that will be able to tell when something is out of tune.
Click to expand...
The nomenclature is a bit different in most digital software. What they call tempo change is an algorithm that changes length but retains original pitch/tone (very lossy). What they call pitch change is an algorithm that changes pitch/tone but retains length (same, very lossy). The only lossless way (okay, relatively lossless, as there is sampling rate conversion) is not to use any of these conplex algorithms, but to simply change the playback rate. That's pretty much the same as spinning the TT slower or faster.
Of course they can hear a change in tune, I can hear it too, that's the whole point :)
 
innuendo1231 said:
Fiddlefye: I don't think 1.82 % of tempo change is that much audible.
Click to expand...

How quickly we all forget that damned near all of our cherished "vintage" gear was built with +/- 20% (at best +/-10%) components the whole way down the "food chain". I have "heard" wow and flutter, but I can probably guess that that it was far beyond 1-2%.
 
innuendo1231 said:
The nomenclature is a bit different in most digital software. What they call tempo change is an algorithm that changes length but retains original pitch/tone (very lossy). What they call pitch change is an algorithm that changes pitch/tone but retains length (same, very lossy). The only lossless way (okay, relatively lossless, as there is sampling rate conversion) is not to use any of these conplex algorithms, but to simply change the playback rate. That's pretty much the same as spinning the TT slower or faster.
Of course they can hear a change in tune, I can hear it too, that's the whole point :)
Click to expand...

Sorry, my comment was directed towards vinyl, not digital......
 
innuendo1231 said:
Heyraz: Hm, the tachometer seems like a good idea. I'll look a used one up.

Fiddlefye: I don't think 1.82 % of tempo change is that much audible. The artefacts that speed-retaining pitch modifiers introduce are very much audible on the other hand. All they do is succesively delete small frictions or put in small iterpolated "spacers" to change the tempo.
Click to expand...
Absolutely I would hear that much change in tempo. Have done.
 
I'm baffled by this thread. The OP wants a strobe disc to show when the platter rotation is 1.8% too slow because that gives him a clearly audible pitch change which he wants. He doesn't care about the inevitable tempo change.
Presumably he has a turntable with a pitch control on it, or how would he change the rotation speed? If the pitch change is clearly audible, why not set it by ear?
 
Sure sure, it would be possible to set by ear, but using a tachometer seems easier and more exact. It could also help with the regular 33,3 setting. And my TT doesn't have a speed dialer, only a hidden screw at the bottom. I'm not sure about my next TT though... There has to be a way to do it on a rega planar 3 too, non? That's what I'm planning on.
 
You must log in or register to reply here.
Back
Top Bottom