TTM 57SL
FOR
SERATO SCRATCH LIVE •
OPERATOR’S MANUAL
2.1
12
CALIBRATING
SCRATCH LIVE
Since Scratch Live is controlled by an analog
signal, there is no guarantee of what state that
signal will be in by the time the software gets to
interpret it. Therefore, Scratch Live needs to be
able to handle a wide range of signals, and be
configurable to use them optimally. Calibrating
is just configuring the software to your situation.
Calibration is equally important for both vinyl
and CD users of Scratch Live.
There are two parts to the Scratch Live control
signal: The directional tone, and the noise map.
Listening to the control vinyl, the directional tone
is the 1 kHz tone. The noise map sounds like
random noise over the top of the tone.
The directional tone provides the current
speed and direction of the record, while the
noise map tells the software precisely where on
the record the needle is currently.
THE NOISE THRESHOLD
A threshold is a lower limit, below which a
process will not occur. In the case of Scratch
Live, the noise threshold is the limit below which
the input signal will not be interpreted as control
signal; in other words if it’s below the threshold,
it is considered noise and ignored.
This setting is necessary because a stylus is
very sensitive, and will inevitably pick up noise
from the environment as well as the signal on the
record, especially in the noisy environment of a
live show.
HOW TO CALIBRATE SCRATCH LIVE
With music playing in the background (from
any source), put your needle on record with the
turntable
stopped
. If you are using CD players,
the same rules apply. Have the CD deck paused
or stopped while calibrating. Ensure the input
level in Scratch Live is set correctly to accept
a LINE level signal.
SEE “PGM INPUTS 1-4” ON
PAGE 7.
In the Setup screen, click and hold the
Estimate
button until the slider stops moving.
Moving the threshold slider to the left will
make Scratch Live more sensitive to slow
record movement, but also more sensitive to
background noise.
Repeat the process for each deck.
Things to remember:
• Your needle must be on the record.
• Your turntable (or CD player) must be
stationary.
• The background music playing must be at a
similar level to which you will play your set at.
• Calibrate Scratch Live every time you play.
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 grounded. 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.
the ScopeS
The scopes on the Setup screen display the
input signal as a phase diagram. The key factors
to look at on the scope display are crisp clean
lines, round shape, and the tracking percentage
in the lower right corner.
Start both turntables or CD players. You will
see green rings appear in the scope view,
as
shown above.
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 close to 85% when your system is
calibrated properly.
CALIBRATION TROUBLESHOOTING
After calibration, the number in the upper right
corner of the scope view should say 0.0 while
the needle is on the record and the turntable is
stopped.
If that number is fluctuating then manually
move the Estimate slider to the right until that
number is stable at 0.0. If you’ve moved the
slider all the way to -24 and its still fluctuating
then you have a grounding or interference
problem somewhere in the chain.
If so, the first thing to check is that the
grounding wire coming from your turntable is
connected to a TTM 57SL grounding post.
Next, make sure that your mixer isn’t sitting
next to a power source such as a power strip or
power box and that your RCA cables aren’t lying
across other power conducting cables.
If you are still experiencing issues, you might
have to adjust the placement of your setup. For
example, make sure bass bins aren’t directly
under the turntables.
If you have trouble getting the rings circular,
you probably need to clean or change your
needles.
If the image appears as a line, then you have a
missing channel. Check your RCA connections
and needles.
SEE “SCOPE READING AND FIXES”
ON PAGE 52.
