Manual-5
Calibrating Scratch
LIVE
The SL 1 interprets the signal on record and communicates with
the software. The signal needs to be clear for Scratch
LIVE
to
perform well. This section describes how to calibrate Scratch
LIVE
to optimize reading the control signal from your turntables or
CD players.
For best results, re-calibrate Scratch
LIVE
each time you move
or make changes to your DJ equipment. To calibrate Scratch
LIVE
, go to the
setup
screen by pressing the button at the top of
the main screen, to the right of the Scratch
LIVE
logo.
Audio input level
By default Scratch
LIVE
is set to accept
phono
level inputs. If you
wish to use CD players, switch to
line
level input. This preference
is stored when you exit Scratch
LIVE
.
Audio output
By default the output of Scratch
LIVE
is
stereo
. You can also
select
mono
output. This setting is saved when you exit Scratch
LIVE
.
Signal threshold
The first step is to set signal threshold. There is always a certain
amount of background noise, particularly when using turntables
in a club environment. With a normal turntable setup, this back-
ground noise is transmitted through the body of the turntable
and platter to the stylus, and can cause stylus feedback. In Scratch
LIVE
, this can cause errors on the reading of the position and
velocity of the control record, resulting in a garbled digital noise
and/or poor tracking.
Place the needle on the record
with the record stopped
.
Click the
estimate
button to measure the background noise and
estimate the appropriate threshold. Moving the threshold slider
to the left will make Scratch
LIVE
more sensitive to slow record
movement, but also more sensitive to background noise.
Tip: If the slider jumps to the far right, then you have a
problem with noise in your turntables/CD players/mixer.
Check all your connections and make sure your equipment is
well earthed. In some situations you will not be able to improve
the signal quality, and you will have to play on regardless.
In this situation, stick to rel mode. (See page Manual-11 for
details)
Scope view
Once you have set the threshold, start both turntables. You will
see green rings appear in the scope view, as shown below.
For optimal performance the inner ring should be as close
to circular as possible. Use the scope zoom slider (
1x
to
16x
) to
zoom in or out as necessary. Use the scope
L/R balance
and
P/A
balance
controls to adjust the shape of the inner ring.
The number in the top left corner of the scope view gives the
current absolute position within the control record or CD. The
number in the top right corner is the current speed in RPM. In
the bottom left is the current threshold setting, and the number
in the bottom right shows the percentage of readable signal – this
number should be at least 85% when your system is calibrated
properly.
Tip: If you have trouble getting the rings circular, you
probably need to clean or change your needles. If the image ap-
pears as a line, then one of the channels of the turntable is not
working. See examples of potential problems and fixes on pages
Manual-23-24.
