AW: AW: AW: DJ techniques in live looping (Re: video on loop turntablism) - also for Jeff Larson!

["Rainer Thelonius Balthasar Straschill" <rs@moinlabs.de>]

> I'm not sure I understand, are you talking about rapid jumps 
> backward and forward, like for example retriggering from the 
> previous subcycle rather than from the beginning of the loop?

No - retriggering would be the DJ moving the needle to a different 
position.
As long as the needle remains on the vinyl, you're not jumping, you're just
moving very fast.

> In both cases though the jumps are instant, if you wanted the 
> sound of a record rapidly changing position we would have to 
> do that with some very large rate shifts up or down that stop 
> when we reach the desired location.  That could probably be 
> done in a script but it would be nicer with a built-in function like:
> 
>     # move to the specified frame by applying a 10x rate 
> shift returning
>     # to the previous rate when we reach the target frame
>     Scratch newFrame 10.0
> 
> Is this closer to what you want?

Exactly. The way I understand this in theory, what a DJ does when he
scratches (i.e. his hand remains in contact with the record, he is not
spinning it) is to move forward and backward in a region of about 1/3 of a
revolution, which would correspond (if I'm not miscalculating here) to
roughly 100ms for an LP.
For making the following description easier with the numbers, I assume that
our "scratch time window" is 128ms long.

I'm sticking with that one-dimensional ribbon controller concept in the
following attempt to a description.

Assume the player doesn't have his hands on the controller, so the loop is
playing along at its set rate and in its set direction (for simplicty, I'm
from now on assuming it's rateshift 0 and forward).

Now, when at at time he puts his hand in the center of the controller (64),
loop playback would pause. 

Now, if the player only moves to the side one controller step, we're not 
any
wiser, because we do not get the speed of his movement, so we need at least
two suceeding movements. Say, he moves from 64 to 60 in the course of 1ms.
That means (with the scratch time windows of 128ms), we move along 4ms in
reverse direction in 1ms. That means Mobius would need to set Rate to 24 
and
Reverse, then pause again.

Does this make sense?