Pitch correction

B

Batoun

New member
Hello

I am transferring some old recordings from tapes to CDs. Due to the age of the tapes and differences between playback speed of different tape players the ENTIRE output is either lower or higher than it should be (for example, an all A notes become almost A flat or A sharp, and so on).

Can someone suggest what's the BEST way to correct this? I am not trying to change pitch of just a few out-of-tune notes rather I need to shift the pitch level of the whole recording.

Thanks!!!
 
Are you recording this to your computer via recording software ? If so, depending on the software you may have a pitch shifter plug-in that will allow you to do just that.
 
I used to do this:

It's probably not the best way to do it, but it gets the job done.

In SoundForge, you can change the sample rate of a wave file without resampling. What this does is change the rate at which the samples are played back. Decreasing the sample rate lowers the pitch/speed, increasing raises pitch/speed (just like adjusting the speed on a tape deck). Once you've found the pitch/speed you want, then resample back to 44.1 (or whatever the 'correct' sample rate is)

The problem is that there's no slider or 'friendly' user interface, you have to enter numbers.

Here's an example of how I did it:

I receive a tape recording that's a bit flat. A is closer to Ab.

I record the song into my computer and save as a wave file (44.1kHz sample rate).

Load the wav into Soundforge.

Increase the sample rate (without resampling) until the song is in tune. (You may get a number something like 45800 Hz)

Then resample back to 44.1kHz.

This works with a SbLive, however I couldn't do this with my Delta because the Delta didn't support playback of 'non-standard' sample rates.
 
If you're feeling brainy (and brave) you could try and figure out how far the originals are out, then record at a different sampling rate, then convert that rate back to 44100 Hz. Bit of maths involved though.
 
Good point.

But if you're taking stuff off old tapes chances are it's not 'perfectly' out of tune. In my case, I had to do it by ear. (ie. 44100 is flat, let's try 44600.... still flat... how about 45600.... oh too much.... 45120.. Got it!)
 
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