Creative 1212M, 1820M owner manual VCA Out, Chorus, Compressor

5 - Effects

Core Effects Descriptions

Chorus

An audio delay in the range of 15-20 milliseconds is too short to be an echo, but is perceived by the ear as a distinctly separate sound. If we now vary the delay time in this range, an effect called chorus is created, which gives the illusion of multiple sound sources. A slight amount of feedback serves to increase the effect. A very slow LFO rate is usually best for a realistic effect, but a faster LFO rate can also be useful with minimal LFO depth (.2). Since this is a stereo chorus, an LFO phase parameter is included which can be used to widen the stereo image.

Parameter	Description
Delay	Sets the length of the delay. Range: 0ms to 20ms.
Feedback	Sets the amount of delayed signal that will be recirculated through
	the delay line. Range: 0% to 100%
LFO Rate	Sets the frequency of the low frequency oscillator.
	Range: .01Hz to 10Hz
LFO Depth	Sets how much the LFO affects the delay time. Increases the
	animation and amount of the chorus effect. Range: 0% to 100%
LFO Waveform	Selectable between Sine or Triangle wave.
LFO L/R Phase	Controls the stereo width by adjusting the phase difference of the LFO
	waveform between left and right channels. Range: -180° to +180°

Compressor

In its simplest form, an audio compressor is just an automatic gain control. When the volume gets too loud, the compressor automatically turns it down. Compressors are useful in musical applications because they allow you to record a “hotter” signal without overloading the recording device.

Since the compressor turns down the gain of the signal, you might wonder how can it make the signal level stronger. A Post Gain control allows you to boost the output gain of the compressor in order to make up for the gain reduction. The overall level is higher and only turned down when the signal level gets too loud. This level is called the Threshold, which just happens to be the most important control on the compressor.

Signal path = Stereo

In

Delay

VCA Out

Level

Control

Threshold	Post Gain
Ratio	Attack Release

E-MU Digital Audio System 65