analog timestretching

[Rene Schmitz]

At 21:19 17.01.1998 -0800, you wrote:
>> "barberpole":
>> No, 'cos in germany the barbers don't have these rotating poles.
>> But there is a word which is topic related: "Zeitdehner" for timestretcher,
>> I've seen this term in anglo-american literature of the 70's, it reffered to
>> a device that has 4 rotating tapeheads 90deg apart, that scans a piece of
>> tape which moves by.
>> This one could do pitchshifting, in the early days of electronic
>> manipulated-tape music.
>>
>
>this sounds very interesting!  I haven't seen or heard one of these
>before.  It seems that in its basic configuration it would do
>timestretching, you'd have to somehow alter the speed of the tape in some
>proportion to the speed of the 4-rotating tapeheads to get pitchshifting,
>and have these things absolutely synchronized. (come to think of it
>maybe I have these things backwards, I have to think about this
>some more) I wonder what external mechanisms can be designed to do
>the speed synchronization?  What are some
>references that mention this technique?
>
>--Harvey
>
The thing is from a book called "electronic music - systems, techniques, and
controls"
by allen strange 
ISBN 0-697-03612-X

I have the second printing from 1972 (this book is older than me!)
so I doubt if its still available, but maybe in some library.

It covers the whole tape techniques of early musique concrete etc.
and the more modern CV-techniques.

It mentions about the timestretcher, that if the heads are moving the same
direction
than the tape the pitch goes down, in the opposite direction it goes up.
It does not say a word, about the technical details, of this intresting thing.


Rene

=(uzs159 at uni-bonn.de)========================
             ,          : 
|") [" |\ | ["          :   This space 
|"\ [_ | \| [_          :   intentionally   
                        :   left blank
                        :
=(http://www.uni-bonn.de/~uzs159)============