Tools One
Tools One is an extremely useful "effect" for various applications.
The level faders allow you to adjust the level of the left and right channel respectively. You can [Shift]-drag to make detailed settings. [Ctrl]-clicking a fader resets it to 0 dB (no level adjustment). Normally, adjusting one fader automatically moves the other as well, but you can make separate adjustments for the channels by pressing [Alt] and dragging.
The two Phase switches let you invert the phase of the left or right channel (or both).
The Algorithm buttons let you adjust the stereo sound image. When none of the buttons are activated, the stereo image will be preserved as is. MS process mode can be used in one of two ways:
To transform an incoming "regular" stereo signal so that it resembles a signal recorded according to the M-S (middle/side) principle. This technique is often used in broadcasting to record the direct signal source (usually a voice) using one microphone, and the ambience using a second microphone positioned at a 90_ angle.
To transform an incoming MS signal into a "regular" stereo signal (to simulate an "XY" recording technique, where neither microphone is placed directly in front of the signal source).
Channel Swap, finally, means that the left channel is assigned to the right side and the right channel to the left side.