Apple Soundtrack Pro 2 - Manual (Page 496)

496 Appendix C Working with Professional Video and Audio Equipment
Now, both audio signals are in phase, but the noise is inverted, causing the noise to be
canceled. At the same time, the original signal gets a little stronger because it is sent
on two wires and combined. This helps compensate for the reduction in signal strength
that occurs naturally on a long cable run.
Any noise introduced into the cable across its long run is almost completely eliminated
by this process.
Note: Unbalanced cables have no way of eliminating noise and are therefore not as
robust for long-distance cable runs, microphone signals, and other professional
applications.
Tips for Choosing Speakers and an Amplifier
Professional audio engineers have to be able to trust the sound coming from their
speakers. When you mix your audio, you need audio monitors that can handle the full
range of audio intensities and frequencies. Ideally, your monitors will have a flat
frequency response from 20 Hz to 20,000 Hz (or 20 kHz). This means that they neither
attenuate nor amplify any frequencies. Flat frequency response is important for critical
listening because the speakers themselves are not “coloring” the sound.
In addition to the speaker quality itself, additional factors affect your audio monitoring
environment:
 Size and materials of the room
 Placement of the speakers within the room, such as distance from walls and angle of
speakers
 Listener position between speakers
Combined signals
(noise eliminated)