Subject:safe at any speed?

Posted by: bunyabunya

Date:6/14/2004 11:16:06 AM

Just for fun I played a 1 7/8 ips open reel tape at 7 ips, which makes a normally boring monotone administrator type person sound like a very irritated alien chipmunk. Then put that track into Sound Forge, and found that a -23 pitch shift returned it to what appears to be a perfectly normal quality voice that is to my ears just fine.

Am I missing something here? Does this mean I can safely speed thru all these hundreds of reels of voices recorded at 1 7/8 ips at four times the speed?

Subject:RE: safe at any speed?

Reply by: Sonic

Date:6/14/2004 12:46:11 PM

For voice, it's probably fine. Just be aware that every time you increase the input speed, you also shift the frequency range prior to the A/D, which means stuff shifted above Nyquist (half the sampling frequency) will be lost in the A/D process.

Again, for voice, you probably aren't losing much audible content at standard sample rates, but if you keep speeding up the tape, it will eventually become noticeable around sibilants, plosives, room noise, etc.

J.