FeedbackDelay = function(audiolet, maximumDelayTime, delayTime, feedback,
                             mix) {
    AudioletNode.call(this, audiolet, 4, 1);
    this.linkNumberOfOutputChannels(0, 0);
    this.maximumDelayTime = maximumDelayTime;
    this.delayTime = new AudioletParameter(this, 1, delayTime || 1);
    this.feedback = new AudioletParameter(this, 2, feedback || 0.5);
    this.mix = new AudioletParameter(this, 3, mix || 1);
    var bufferSize = maximumDelayTime * this.audiolet.device.sampleRate;
    this.buffers = [];
    this.readWriteIndex = 0;
}
Delay line with feedback

**Inputs**

- Audio
- Delay Time
- Feedback
- Mix

**Outputs**

- Delayed audio

**Parameters**

- delayTime The delay time in seconds.  Linked to input 1.
- feedback The amount of feedback.  Linked to input 2.
- mix The amount of delay to mix into the dry signal.  Linked to input 3.

@constructor
@extends AudioletNode
@param {Audiolet} audiolet The audiolet object.
@param {Number} maximumDelayTime The largest allowable delay time.
@param {Number} delayTime The initial delay time.
@param {Number} feedabck The initial feedback amount.
@param {Number} mix The initial mix amount.