Re: (idm) lock grooves

From Andrew Duke Cognition
Sent Tue, Jan 5th 1999, 15:41

Hmmm....  Irene:  ever peel an orange or an apple with
a knife and try to peel the whole thing so that the peel is
a continuous strip and all in one piece?  ok, when you play
the usual forward playing record, the needle starts in on
the outside of the record and continues in a continuous groove
until the end of the track.  This groove runs around the record
and takes the needle toward the center of the record.
a lock groove, however, does not take the needle further
toward the center of the record because instead of it
continuing to flow (like the orange/apple peel example above)
and move on, it is a loop of *one time* around the record.
there are two ways you can do a lock groove;
#1:  have the song play for awhile and then end in a lock
groove
#2 just have a one revolution (i.e one time around the turntable)
groove (damn, this would be easier to draw on paper)

so anway, the lock groove works like this: instead of
playing one revolution of the record and the continuing
on with the groove, the groove is locked so it's end is
joined to its beginning. like a dog trying to catch its tail,
it goes around and around.  a lock groove will play
until infinity (or the power or your needle goes out ;)
whereas the regular groove in a record moves the needle
forward until it gets to the run off matrix (the part that
surrounds the label) at the end of that side of the record.
ever wonder why the needle doesn't run onto the label
and try to play the paper?  it's because there's a crude locked
groove at the end of every side of a record.  occasionally,
though, this will be pressed badly, and that's why sometimes
your needle jumps onto the label and tries to play the paper
label.  hope this makes sense.  andrew :)

Irene McC wrote:

> On 4 Jan 99,  Joanisse, Robert wrote:
>
> > how to use a razor to cut up
> > the last groove on a record into a lock groove.
>
> Never having seen a lock groove, could somebody please explain
> how these work?  Does the needed somehow return back to the
> beginning and repeat play until you physically move it off?
>
> I
> *