ACIDPower!

Addendum

Tempo influences the pitch shifting of loops in a project. One very important tool for recognizing this distortion appears in ACID in the Track Header area on the left side of the tracks. As the tempo slider is dragged left and right to decrease and increase the tempo, the Multipurpose slider is replaced by a bar with a percentage on it (see the figure below). This represents the speed difference between the project's tempo and the loop's original tempo. Different loops in a project are effected to different degrees, so if you are trying to prevent distortion to a particularly important loop in a project, you should try to select a tempo that minimizes distortion to that loop. Click and hold the Multipurpose slider to view the time distortion information.

Keep in mind that the total distortion of the loop is caused not only by tempo or time stretching, but is also caused more directly by pitch shifting. As you know, ACID automatically adjusts loops with key information to match the project's key. The purpose of this is to keep all of the many loops in a project in tune, despite the disparate keys they were originally recorded in. The result of this, of course, is that the pitch of a loop as played in ACID is different from the source pitch of the recording. This always results in some loss of fidelity. Often, this distortion is unnoticeable, but as a loop's pitch is bent more and more, the distortion eventually becomes more and more apparent, and is eventually unacceptable.

So the key to keeping the fidelity of a loop used in ACID as high as possible is to change it's pitch as little as possible. Since a project is a mix of many different loops in many different keys, it is impossible to find a project key that is able to minimize distortion for all loops. Instead you should pick a project key that minimizes the distortion of the most important loops in your project. Often, this will be vocal tracks or solo instrument tracks. In other words, if you are using a vocal loop that was recorded in D, the project key should also be set to D.

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