Pitch shift after gain change

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audibell
Posts: 7
Joined: Mon Apr 25, 2005 4:27 am
Location: New Orleans

Pitch shift after gain change

Post by audibell »

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Hi Mr Chris: this is a strange occurence which is a bit of a nuisance.
I transfer a 16bit/48k 60 minute file from DAT via spdif out to Echo MIA spdif in and record conventionally to a 16/48 wav file. Latest drivers from Echo.
Sometimes the overall gain of the file is a bit low so I increase by 2 or 3 dB and let GW crunch away +/- 5mins (P IV, 1megRAM, 2ndary NTFS HD)
Occasionally, I find the pitch is lowered from 1.000 (unity) to 0.94. With the speed control on the device app I can return it where it ought to be by increasing to 1.06. I know the pitch is lowered by a semi-tone or more by comparing it to my piano. I leave the deivce app at 1.000 and use the Pitch shifter to make the appropriate (to my ears) adjustment.
Then, after I have pitch shifted the whole file by the appropriate amount, 1.06, and saved it, I come to find out when I next open the file that it's too high by - 1.06!! Now it's a semitone or more higher. So my only option is to re-record the DAT signal all over again, and re-save it to another close name. But this is a nuisance because it's not consistent and 600meg files all overtheplace etc etc. What am I failing to do in the Volume change section, please?
I don't resample until I have completely finished tweaking the file. I favor a minimalist approach, I record without compression, I don't use reverb or EQ (I move the mics) and all I need to do is remove clapping, fade in either ends and adjust the gain, usually upwards a bit.
This doesn't happen all the time. I have tried rebooting and re-opening but it doesn't always clear the problem My PC is audio only, no concurrent processes, no print drivers, no system sounds, screensavers etc. Needless to say this doesn't happen in CoolEdit; I like GW's interface and would commit if this gremlin would stay away.

GoldWave Inc.
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Re: Pitch shift after gain change

Post by GoldWave Inc. »

I do not know of any way the pitch could be affected by a simple volume change. The problem is most likely caused by a glitch in the DirectX sound driver for the card. Whether it is on the playback side, the recording side, or both may take some work to figure out. Immediately after recording a file, save it and see if it plays at the correct pitch in other software that does not use the DirectX driver. If it sounds correct in other software, but not when played in GoldWave, then it is only on the playback side and you can ignore the problem (don't try to correct it) until Echo has a better DirectX driver.

Chris

gordonh
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Joined: Wed May 11, 2005 12:25 am
Location: Geelong, Australia

Pitch Shift after gain change

Post by gordonh »

I just wonder if this isn't related to a confusion between 48k and 44.1k sample rates somewhere along the way. I had an instance recently where I did some work for someone and then found the final product was pitch shifted down by about a semitone - and the reason was that the original files were recorded at 48k, but I was not aware of that, and when I loaded them into Logic to work on them (at 44.1k), it simply shifted the pitch down and showed the files as being longer than expected.

GoldWave Inc.
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Re: Pitch Shift after gain change

Post by GoldWave Inc. »

You can use the Effect | Resample command to convert a 48kHz file to 44.1kHz.

Some defective DirectX sound drivers record at the wrong rate, such as recording at 48kHz when 44.1kHz should be used. Update the driver to correct that problem.

Chris

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