Digidesign Control 24 ユーザーズマニュアル

About Signal Levels

Rule #1 in adjusting input gain is to never clip 
the signal in Pro Tools. It is OK to occasionally 
trigger the red peak indicator on a track’s meter, 
but clipping causes digital distortion that can 
render your track unusable.

Within the preamp circuit, however, there is a 
balance for optimal gain structure and signal in-
tegrity that varies greatly, depending on the dy-
namic range of a given signal. This balance is 
highly subjective, and can vary depending on 
program material, microphones used, or an en-
gineer’s preference. 

The general guidelines—other than to avoid 
clipping within Pro Tools—are to keep levels 
low enough to avoid clipping (and associated 
distortion artifacts), yet high enough to stay 
clear of the noise floor (which is very low with 
these mic preamps!).

There are no absolute rules or strict formulae for 
attaining optimal levels. Depending on the sig-
nal character and sonic context, there are occa-
sions where this balance ratio can shift signifi-
cantly in either direction.

There are times when you want to avoid one ex-
treme more than the other, and certain soni-
cally-pleasing textural results can be achieved 
through the use of atypical gain structure.

For example, some engineers find certain distor-
tion characteristics to be texturally pleasing, 
and might even route an already-recorded signal 
back through a microphone preamp a second 
time to achieve a certain effect. While this prac-
tice is not necessarily recommended, it is never-
theless cited as an example of the subjectivity of 
preamp levels, and the use of preamps for pur-
poses other than merely raising a microphone 
signal to recordable level. 

You will have to experiment to find the optimal 
gain structure for various contexts, and to be 
able to estimate settings based on source and 
microphone placement and types.