You will now need to adjust the volume level of each track. If you were prudent, you recorded your tracks at a sufficiently low volume so that such adjustments will be necessary. There are several considerations here. First, any volume increases have got to watch out carefully for "clipping," an excessive volume level that truncates the tops of the waveforms and causes very annoying distortion. Second, we must make sure that we do not ruin the fundamental dynamics of the piece. An intentionally quiet passage should not be brought up to the level of a loud passage, simply because we can do it. And, we should preserve the dynamic range of different tracks within an LP: if a ballad on an LP is mixed at a lower volume than a rock piece on the same LP, that distinction should be preserved. Cool Edit/Adobe Audition provide some great tools for giving us total control over the volume, and we will explore these now.
On the menu bar, if you open effects/amplitude, you will see several options, of which three will concern us here: "amplify," "hard limiting," and "normalize." A fourth option, "channel mixer," will mainly pertain to our discussion of mono recordings.
1--Here is the "amplify" control box:
Note that there are separate controls for each channel so that the volumes can be controlled independently of each other (unless the "Lock Left/Right" option is checked. Also note that the amplitude of a waveform can be reduced as well as increased. You may notice after you record a record that one channel is at a consistently lower level than the other channel. If you can't perceive any reason for this discrepancy, you can assume that either the vinyl is somewhat defectively recorded, or your equipment is giving a slightly louder signal from one channel than from the other. In either case, you can rectify the situation here by amplifying one channel only.
2--If we go to effects/amplify/normalize, we get the normalize control box:
Cool-Edit Pro Normalize Control Box
Now when we choose the "normalize" effect, the software looks for the loudest point of the waveform, and then raises (or lowers) the amplitude of the entire waveform until the volume reaches a particular percentage of the clipping point. Every point in the waveform is amplified equally, so that the original dynamics of the piece are preserved. The default figure of 98% is a typical percentage figure for normalization. Note that the process discussed next, "hard limiting," actually has the effect of compressing the waveform, so that softer passages will effectively be amplified more than the loudest passages. This can greatly increase the apparent loudness, although the peak amplitudes may not be any greater than with "normalization."
3--If we go to effects/amplitude/hard limiting, we are presented with the hard limiting control box, which looks like this:
Cool-Edit Hard Limiting Control Box
"Hard Limiting" differs from straight amplification in that when the peak volumes approach the "clipping" distortion level, the "hard limiting" software begins to attenuate the waveform drastically. This can greatly reduce the danger of amplifying beyond the point of clipping. Note that this control box does not have separate controls for the left and right channels (though offers to gather clipping statistics for both channels separately). That's quite all right. If we want to "hard limit" just one channel, we can use our keyboard up-down arrows to select one channel or the other before we execute the "hard limiting" operation. I have found that the default "Limit Max Amplitude to -.1dB" setting is just about right, so I never mess with it. The same goes for the "Look Ahead Time" setting of 7 and the "Release Time" setting of 100. The "Boost Input" box is the figure that you will adjust to a desired decibel level of gain. Remember that with hard limiting you are not only increasing the loudness but also to a greater or lesser extent altering the dynamics of the piece, so use it with caution.