jpetersen
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How to drop rate from 88k2 to 44k1 and so slow to half-speed (RESOLVED)
I know this is in Craig's book and it has been discussed before, but I just cannot find it. I have some 40 year old reel-to-reel tapes to digitize. They were recorded at 1 3/8 ips but my machine only manages 3 3/4, so I recorded at 88k2, intending to drop to 44k1, thereby also stretching and slowing down the recording to the original speed. I remember this is done with the loop generator (doubleclick on clip), but I cannot remember what next. All the BPM, key and other controls are greyed out, and the stretch menu on/off pops up a message box saying this editing operation is not allowed. Help!
post edited by jpetersen - 2017/10/02 21:14:10
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randyman
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Re: How to drop rate from 88k2 to 44k1 and so slow to half-speed
2017/09/30 19:05:21
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Have you looked around for a 1-3/8 ips machine? It could be a lot simpler and easier to get it done - especially there is a lot of it to do. (just thinking out loud here) Are these two track? or more? (I recall doing 8 tracks at that speed back then..) That being said, I agree there should be a way to digitally do it. Keep looking. If you know it's in Craig's book, it seems like that would be a cheap investment to get it done. Good luck 
A rack of noisemakers is not a definitive substitute for creativity. (though it does seem to help) what I spend my lunch time doing: (don't laugh - its just for fun!) www.soundclick.com/rnewburn
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scook
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Re: How to drop rate from 88k2 to 44k1 and so slow to half-speed
2017/09/30 19:34:27
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Could be done by changing the file header to 44.1 using sox or the like. The command in this case would be sox -r 44.1k infile.wav outfile.wavThen import the new wave into a new project set at 44.1.
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THambrecht
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Re: How to drop rate from 88k2 to 44k1 and so slow to half-speed
2017/10/01 11:49:14
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This is an absolute NoGo.
If you slow down to half speed you will lose all high frequencies over 8kHz.
Because your tape machine does NOT play at double speed 15kHz as 30kHz !!. Your tape machine will not play frequencies over 16 to 18 kHz - and then you halve this to an upper limit of 8 kHz.
If you don't want to buy a machine:
Record with 96kHz or 88kHz. Then slow down the files with Steinberg Wavelab. There is a test version that will work 14 or 30 days. WaveLab makes the best results by slowing down tapes.
We digitize tapes, vinyl, dat, md ... in broadcast and studio quality for publishers, public institutions and individuals.4 x Intel Quad-CPU, 4GHz Sonar Platinum (Windows 10 - 64Bit) and 14 computers for recording tapes, vinyl ...
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Anderton
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Re: How to drop rate from 88k2 to 44k1 and so slow to half-speed
2017/10/02 15:22:30
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jpetersen
I know this is in Craig's book and it has been discussed before, but I just cannot find it.
I have some 40 year old reel-to-reel tapes to digitize.
They were recorded at 1 3/8 ips but my machine only manages 3 3/4, so I recorded at 88k2, intending to drop to 44k1, thereby also stretching and slowing down the recording to the original speed.
I remember this is done with the loop generator (doubleclick on clip), but I cannot remember what next.
All the BPM, key and other controls are greyed out, and the stretch menu on/off pops up a message box saying this editing operation is not allowed.
Help!
You do not want to use DSP to do this, the following will do the job. 1. Slip-edit (not slip-stretrch) the end of the clip so it's twice as long, then bounce the clip to itself. 2. Open the clip in the Loop Construction View. 3. Choose Clip > Stretch On/Off and set the Threshold to 0 (i.e., no transient markers). 4. Change the pitch semitone parameter to -12. The file will now play at half speed. Bounce the clip to itself...done. This is the same result as slowing down tape by half-speed. Note: In Step 3, you do NOT want Loop On/Off enabled. This is not about looping. Also Threshold must be set to 0.
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jpetersen
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Re: How to drop rate from 88k2 to 44k1 and so slow to half-speed
2017/10/02 21:13:31
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Funny, two threads with exactly the same issue!
@Craig: at step 3 I get a message box saying "editing operation is not allowed."
@randyman: It was recorded on a 1/4" mono domestic BSR radiogram. I did buy another machine which turned out to have other issues and is unusable.
@THambrecht: As I said, I recorded at 88k2. I doubt the material contains more than 8kHz even if I did play it back on a 1 3/8" capable machine. It's just speech. I have Wavelab but cannot figure out how to do it.
@scook: Yes, that's the way I went. I downloaded the WAV file specification and wrote a little program which changes the nSamplesPerSec tag from 88200 to 44100.
And whaddaya know? It works! Problem solved!
Many thanks to all for your help, much appreciated.
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Anderton
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Re: How to drop rate from 88k2 to 44k1 and so slow to half-speed
2017/10/02 21:23:30
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jpetersen
@Craig: at step 3 I get a message box saying "editing operation is not allowed."
Could be that the file is too long for the LCV to handle.
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jpetersen
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Re: How to drop rate from 88k2 to 44k1 and so slow to half-speed
2017/10/02 21:53:47
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jpetersen
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Re: How to drop rate from 88k2 to 44k1 and so slow to half-speed
2017/10/16 23:04:58
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THambrecht
This is an absolute NoGo.
If you slow down to half speed you will lose all high frequencies over 8kHz.
Because your tape machine does NOT play at double speed 15kHz as 30kHz !!. Your tape machine will not play frequencies over 16 to 18 kHz - and then you halve this to an upper limit of 8 kHz.
Well, I just wanted to report that you were right. Even though it was just speech, the results were disappointing. Not only that, there is a high-pitched digital fizzing from the interface which I is inaudible normally but comes into audio range by slowing the speed by half. So much for recording at 88k2.
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