View Single Post
Old 11-07-2016, 08:26 PM
Musicat Musicat is offline
Charter Member
Join Date: Oct 1999
Location: Sturgeon Bay, WI USA
Posts: 20,033
Originally Posted by terentii View Post
Was this the case in 1959, though?
I can't provide experience from that era. My example was from ca. 1973.

But multi-track recording was being experimented with in the 1950's and it doesn't seem a stretch for someone with some engineering chops to make such a multi-speed device then. Les Paul used many tracks, although his early recordings were not multi- in the sense used later, but sound-on-sound, where previous recordings were added to new takes, building up layers. Even Patti Page had a hit record in 1958, Everybody loves a Lover, where she sang a duet with herself.

Besides, for chipmunks, all you need is a recorder with 2 speeds, something almost every recorder had, home or studio.

Originally Posted by Jinx View Post
How could the average person do this in 1959 or even now? I don't see typical recording devices coming with potentiometers (pots) to tweak playing speed. How could this be "induced" into a device of the 50s or even today? Could you place a potentiometer in-line with the current to change resistance and therefore vary rpms?
That's not the way it is usually done. First, most recorders had 2 or 3 speeds built-in. If that was not sufficiently flexible, consider what I did in my own lab, ca. 1974 (presumably I could have done it in 1958):

I bought a used 100 watt mono power amp, and an audio frequency generator. I rewired a Pioneer open reel RT 1011 recorder, severing the power lines to the synchronous capstan motor (synchronous means the speed is controlled by the frequency, usually 60 hz powerline in the USA). I powered the capstan motor from the power amp, driven by the audio generator. It worked perfectly.

I could control the capstan, and therefore the tape speed by changing the audio generator's output. 60 hz was standard, but I could go from about 40 to 120 hz with the attendant pitch/speed variation of the tape. And I could double or halve the speed with the built-in speed change (7.5ips to 15ips or 3.75ips, for example).

(The 40-120 range was limited since the capstan motor wasn't designed to be much different from 60.)

Now, it's much easier. You can change the pitch without altering the speed, or vice-versa, with a free program for your PC.