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Time stretching/pitch shifting without DSP, possible or not?
bennetng
post Sep 18 2012, 10:47
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I mean time stretching without changing pitch and pitch shifting without changing speed.

I ask this because my friend recently purchased a turntable (Stanton ST150) and it has time stretch function.

http://www.stantondj.com/pdf/products/turn...t150_manual.pdf

The manual says

QUOTE
Note: This turntable has separate analog and digital circuits. If you are
looking for a purely analog signal, use the Phono output. For access to
the Key correction feature use the Line output or S/P DIF output.


QUOTE
Note: Key lock and Digital output
processing is only available when the LINE
output is used.


So from my common sense and English level (not my native language), the line out is in fact converted from digital. But my friend insisted on thinking that the processing is done in analog domain and said if EQ can be done in analog domain, why time stretching/ pitch shifting can't?

What is your opinion?
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John_Siau
post Sep 18 2012, 19:36
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I seem to recall that there were analog frequency-shift devices that were built with "Bucket Brigade Devices" (BBDs). A BBD device passes a charge down a long string of switched capacitors, and can be used as an analog audio delay line. These BBD frequency-shift devices were sampled analog systems, and not digital.

The BBD would be loaded with a short segment of audio, and then played back at at different shift rate. The segments of audio were simply spliced together by repeating or omitting chopped segments. These systems could frequency shift, but could not time stretch.

In many cases, time stretching was accomplished by using a tape recorder, and the frequency-shift device was used to restore a normal pitch.


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John Siau
Vice President
Benchmark Media Systems, Inc.
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Posts in this topic
- bennetng   Time stretching/pitch shifting without DSP   Sep 18 2012, 10:47
- - dumdidum   this is def done digitally. the point is, many DJ...   Sep 18 2012, 11:01
- - bennetng   QUOTE but people are still fully convinced that th...   Sep 18 2012, 14:14
|- - dumdidum   QUOTE (bennetng @ Sep 18 2012, 15:14) QUO...   Sep 18 2012, 15:52
|- - greynol   QUOTE (bennetng @ Sep 18 2012, 06:14) QUO...   Sep 18 2012, 18:15
|- - bennetng   QUOTE (greynol @ Sep 19 2012, 01:15) QUOT...   Sep 18 2012, 18:26
|- - greynol   QUOTE (bennetng @ Sep 18 2012, 10:26) Ple...   Sep 18 2012, 18:37
- - mzil   It is possible to do analog pitch shifting althoug...   Sep 18 2012, 16:43
|- - pdq   QUOTE (mzil @ Sep 18 2012, 11:43) It is p...   Sep 18 2012, 17:26
||- - benski   QUOTE (pdq @ Sep 18 2012, 12:26) QUOTE (m...   Sep 18 2012, 17:49
||- - pdq   QUOTE (benski @ Sep 18 2012, 12:49) There...   Sep 18 2012, 17:56
|- - Arnold B. Krueger   QUOTE (mzil @ Sep 18 2012, 11:43) It is p...   Sep 20 2012, 19:11
- - bennetng   So are there any dedicated analog machines doing t...   Sep 18 2012, 17:06
- - dumdidum   QUOTE (pdq @ Sep 18 2012, 18:26) QUOTE (m...   Sep 18 2012, 17:42
|- - benski   QUOTE (dumdidum @ Sep 18 2012, 12:42) QUO...   Sep 18 2012, 17:50
|- - mzil   QUOTE (benski @ Sep 18 2012, 12:50) QUOTE...   Sep 18 2012, 18:57
- - John_Siau   I seem to recall that there were analog frequency-...   Sep 18 2012, 19:36
- - mzil   A 1968 example of the tape based "Electro Rat...   Sep 18 2012, 19:44
- - John_Siau   Here is a link to an old BBD data sheet from 1975....   Sep 18 2012, 19:47
- - bennetng   Thanks for the explanations. Then I guess the anal...   Sep 18 2012, 19:59
- - krabapple   On a two recent remixes by Steve Wilson (one the 1...   Sep 19 2012, 17:30
|- - bennetng   Most samplers/romplers support this kind of pitch ...   Sep 19 2012, 17:55
|- - mzil   QUOTE (krabapple @ Sep 19 2012, 12:30) It...   Sep 19 2012, 18:30
- - greynol   I don't think pitch correction which also chan...   Sep 19 2012, 18:46
|- - krabapple   QUOTE (greynol @ Sep 19 2012, 13:46) I do...   Sep 19 2012, 20:40
- - greynol   From what I understand of Wilson, he's not exa...   Sep 19 2012, 21:46
|- - krabapple   QUOTE (greynol @ Sep 19 2012, 16:46) From...   Sep 20 2012, 00:03
- - krabapple   so, just for giggles, using Audition 1.0 's ...   Sep 27 2012, 00:09


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