M-Audio Torq 2.0 [167/171] Stereo separation

Appendix B: Torq Vinyl Control System

162

Torq 2.0 User Guide

Another technique that can be used by digital DJ's is Relative tracking mode in the software. When using Rel-

ative mode, Torq ignores the position of the needle on the record. When you load up a new track onto a Deck,

you can place the needle anywhere on the record and the music will start from the beginning once you start

the record. By putting the needle in a different place, it keeps you from burning the same area of the record

over and over again, thus extending life

Lastly, Torq has a Lead-In preference that offsets the start of the music relative to the start of the control vinyl.

If you've burned the beginning of the vinyl, increment the Lead-In by one. This will add a rotation to the re-

cord before music starts. Once the new area is burned, increment the Lead-In again. Each increment will make

the music start further into the record.

Ground Hum

One factor that can inhibit the functionality of the vinyl tracking is a ground loop. A ground loop manifests

itself as a low hum or buzz in the audio system, a noise that never stops even when the record is not playing.

As explained earlier, Torq listens to the pitch of the pilot tone to determine speed and direction. Torq can be-

come confused if there is a ground hum mixed in with the pilot signal. Torq might “lock” to the ground hum

instead of the pilot tone causing the playback speed to be incorrect. It could also contaminate the position

stamps making them impossible to read (position stamps are scattered throughout the audio spectrum). If you

listen to the record directly (such as by clicking the Line In button in Torq), you should be able to hear if a

ground loop is present. If so, you'll need to change the wiring of your system, possibly plugging the turnta-

ble(s) into different power outlets or by changing the location of the turntables. Once the ground hum is

gone, tracking will be improved.

Stereo Separation

The vinyl tracking system relies on two channels of audio signals (left and right) played back from the control

vinyl. Torq will judge the phase-offset and other aspects of the signals to determine direction and position. If

the left and right channels are not separate when they enter the computer, Torq will not be able to perform

any phase-offset calculations and the system will fail.

There are two main causes of poor stereo separation: wiring and stylus. The first problem will occur if there is

a short or other problem with the wiring/connections of the turntable to the computer. If there is a short in

the turntable that causes left and right channels to mix together (even partially), Torq won't work properly.

Similarly, if the stylus/cartridge is worn to the point where signals on the left are bleeding through into the

right (or vice versa), the vinyl control system will also fail. This problem can be difficult to diagnose-a turn-

table test record is recommended. The test record will play sounds isolated to one channel or the other. If you

hear the sound out of both channels when it should be out of only one, then you've got a stereo separation

problem. Try a new stylus/cartridge. If that doesn't fix the problem, have the turntable checked by a profes-

sional.

Poor Frequency Response

Torq's position stamps are scattered throughout the audio frequency spectrum. Some digits will be in the low

(bass) frequencies while others will be in the high (treble) frequencies. In order for Torq to read all the digits

in a position stamp, you will need a stylus/cartridge that outputs this wide spectrum of audio frequencies. If

you have a worn out needle, the high-frequency signals might not be reproduced properly, making it difficult

for Torq to read the position stamps. If you find that scratching works but needle drops don't, you may have

a worn needle.