.NOISE REDUCTION


Compression tends to amplify the noise in a source, because when the signal is below threshold, the compressor raises the again. A possible antidote for noise is gentle low level expansion, especially at selective frequencies. Tape hiss, preamp hiss, noisy guitar and synth amplifiers can be perceived as problems or just "part of the sound." But when you think the noise is a problem, don't be overzealous in its removal. I often refer to the sound of poorly-applied noise reduction as "losing the baby with the bathwater." The key to good-sounding noise reduction is not to remove all the noise, but to accept a small improvement as a victory. Remember that louder signals mask the hiss, and also remember that the general public does not zero in on the noise as a problem. They're paying attention to the music, and you should, too!

1 to 4 dB of reduction in a narrow band centered around 3-5 kHz can be very effective and if done right, invisible to the ear. Do this with the Finalizer's multiband expansion. Start by finding a threshold, with initially a high expansion ratio, fast attack and release time. Zero in on a threshold that is just above the noise level. You'll hear ugly "chatter" and bouncing of the noise floor. Now, reduce the ratio to very small, below 1:2, perhaps even 1:1.1, and slow the attack and release until there is little or no
perceived modulation of the noise floor. The attack will usually have to be much faster than the release so that fast crescendos will not be affected. This gives gentle, almost imperceptible noise reduction. Use the Finalizer's compare button to see how successful you've been. Hiss can be dramatically reduced, but make sure you haven't damaged the music along with it. The thresholds in the other two bands may have to be set very high (expansion off). The Finalizer's look-ahead delay actually allows the Expander to open before it's hit by the signal, thereby conserving transients.


Know Your Limits

Noise reduction through simple expansion has its limits. If you're not satisfied, you may have to put the recording through specialized dedicated noise-reduction units, which employ algorithms that took years to perfect. In Noise-Reduction, you do get what you pay for, and if it's inexpensive, it's either ineffective, or probably no good.


Quelle: Bob Katz