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On a Technics 1210 Mk2 turntable there is +/- 8% pitch control.

Let’s say I have a track in Camelot key 11A at 130bpm. If I was to move the pitch from 0 to +1, how does this affect the change in key? Does this transpose up to 12A?

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  • What are 11A and 12A?
    – phoog
    Nov 8 '21 at 20:15
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    @phoog 11A and 12A correspond to F# minor and C# minor, respectively. See What is the difference between the Circle of Fifths and the Camelot Wheel?.
    – Aaron
    Nov 8 '21 at 20:27
  • @aaron This link is a treasure! And I'm not only talking about the op or the accepted answer ;)
    – Tom
    Nov 8 '21 at 22:39
  • When I was 11, I used to play lps (33rpm) at 16rpm, to learn guitar solos. It took everything down an octave, pretty well, so no re-tuning. Seems like it's a direct relationship - speed against pitch.
    – Tim
    Nov 9 '21 at 9:35
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    You're asking if speeding up the record by 1% will transpose the pitch by 7 semitones. You should really try to get an idea how big 7 semitones is, that's an important thing to understand. You would need to increase the playback speed by 50% (and thus get a 195 bpm) to get the change you're talking about. Nov 9 '21 at 10:20
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If you increase the speed by 1% then all of the frequencies played back increase by 1%. If there's an instrument tuned to A=440 Hz, it will sound like it has been tuned to A=444.4 Hz. This is only about 17 cents sharp, so still rather closer to A than to B flat. If you turn it up to 8% over the standard speed, the pitch will be about 133 cents sharp, so somewhat higher than B flat, but still closer to that than to B natural.

Pitch and frequency have a logarithmic relationship, so the proportional increase in frequency results in a linear increase in pitch, which means that pitch relationships in any key change will be preserved.

Thanks to Aaron's comment, I can also add that in order to go up or down by s fifth, which is one step on that circle, you have to increase or decrease the speed by just under 1.5 times, which will change your BPM from 130 to 195 or to 86⅔.

The upshot of this is that if you're using the turntable to make small adjustments in the tempo of a song, I suspect that the change in tempo is more important to you than the change in pitch. If you make larger adjustments, the problem will be less the change in pitch than the change in tone quality. Sped-up songs will start to sound a bit thin and slowed-down songs will sound thick and droopy.

As to the Camelot wheel, a gradual increase in pitch corresponds to moving 5 steps counterclockwise. As you increase the speed of the turntable, you get farther from 11A and closer to 6A until you arrive at 6A. Then you start moving toward 1A. If you start at 1A and increase the pitch, you wrap around to 8A, then 3A, then 10A, and so on. It's topologically confusing, but the point of the wheel is to express that 11A and 12A are close musically even though they aren't close in pitch. This is similar to how a shade of red and a shade of green might complement each other better than two shades of red even though the shades of red are closer to each other.

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    @user1079505 thanks. Something seemed wrong there but I was cooking dinner so I didn't manage to check my arithmetic.
    – phoog
    Nov 8 '21 at 21:12
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    About tone quality: Changing speed messes with the RIAA curve. So if you play too fast you loose bass, if you play too slow you gain a lot of bass.
    – Lazy
    Nov 8 '21 at 22:04
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With equal temperment one semitone is the factor 2^(1/12). Thus to get from a factor f to a change in pitch you need to take log(f, 2^(1/12)) (which is the log to the base 2^(1/12), which is also log(f)/log(2^(1/12)) = 12 log(f)/log(2)).

So 1% (f=1.01) results in about 17 cent, 3% in about one quartertone, 6% in about one semitone and 8% in abut 1 semitone and 33 cent.

I dont know what 11A and 12A are supposed to be, so I hope that this is helpful enough.

EDIT: From what I’ve gathered that Camelot thing is simply a labelled circle of fifths. So no, 1% won’t take you from 11A=F# minor to 12A=C# minor. But about 6% up will take you from 11A to G minor=6A.

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