# Difference between revisions of "ER-301/Manual Loops"

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## Applications

No one really knows. The leading theory at the moment is that this is just another (interesting) way to scrub through a sample.

## Description

This special-purpose sample playback unit will loop a CV-selected portion of its attached sample. The loop start point and length are both adjustable under CV control. Furthermore, setting the loop length parameter to a negative value means that the playback direction is reversed.

## Parameters

### sync

 Control Type Has Sub-chain? Sub-chain Parameters Behavior Threshold yes threshold (-1 to 1) trigger

A pulse to this parameter will reset the play head to the beginning of the loop. Use this behavior to synchronize loop playback with other material.

### V/oct

 Control Type Has Sub-chain? Sub-chain Parameters Fader Scale Pitch yes transpose (-3600¢ to 3600¢) logarithmic ratio

This parameter is used to transpose the pitch of the sample up or down according to an incoming modulation value (typically one of the calibrated inputs from the ABCD matrix). Its effect multiplies the speed parameter like this:

$\displaystyle \text{Playback Speed} = (\text{base speed}) * 2 ^{\text{V/oct}}$

For example, if the speed parameter is equal to 0.5x and this V/oct parameter is set to 2400¢, then the resulting sample playback will be 2x (i.e. 2400¢ = 2 octaves which is 4x and the base speed was 0.5x for a total of 2x). The V/oct parameter is identical to the pitch (or exponential FM) control on a VCO.

### speed

 Control Type Has Sub-chain? Sub-chain Parameters Fader Scale Gain/Bias yes gain (-10 to 10) bias (-3 to 3) linear

The speed parameter controls the base speed of sample playback. It is called the base speed because the final playback speed will be affected by the V/oct parameter described above. It is similar to the linear FM control on a VCO. If the V/oct parameter is zero then the sample playback speed is exactly equal to the value of this parameter. See the V/oct parameter for a complete description of the calculation of sample playback speed.

### start

 Control Type Has Sub-chain? Sub-chain Parameters Fader Scale Gain/Bias yes gain (-10 to 10) bias (0 to 1) linear, proportional to entire sample

The value of this parameter determines the starting position of the loop. The entire sample is mapped to the interval [0,1] such that 0 is the beginning and 1 is the end.

### len

 Control Type Has Sub-chain? Sub-chain Parameters Fader Scale Gain/Bias yes gain (-10 to 10) bias (-1 to 1) linear, proportional to max.len parameter

This parameter sets the length of the loop as a proportion of either the entire sample length, or, the value of the max.len parameter, whichever is smaller. For example, if the sample is 60s long but the max.len parameter is set to 12s, then a value of 0.25 would set the loop length to 3s (= 0.25 x 12s). A negative length causes the loop to play in reverse.

### max.len

 Control Type Has Sub-chain? Fader Range Fader Scale Simple Fader no 0s to 36s seconds

This parameter is used to set the range of the len parameter to the desired scale of loop lengths (in seconds). In other words, it sets the actual loop length (in seconds) used when the len parameter (above) is set to one. See the len parameter description for more details.

### fade

 Control Type Has Sub-chain? Fader Range Fader Scale Simple Fader no 0 to 250ms linear time

The output might jump discontinuously when the play head loops at the beginning (ending) of the sample, or, when a trigger resets the play head position. When this happens, a fade is used smooth over the discontinuity in the output thus suppressing pops. This parameter sets the length of the fade used.

 If you are using a single cycle wave sample to recreate a wavetable oscillator then it is recommended that you set this parameter to zero.