Guitar Amp 4 - ENSONIQ DP/4+ Reference Manual

GUITAR AMP 4

Guitar Amp 4 is designed to recreate the warm sound and "touch" of vintage class "A" tube
guitar amplifiers. This is done by carefully emulating their distortion characteristics. The
waveshaping table used in creating this guitar amp simulation is a symmetrical table. A
symmetrical table produces odd harmonics (no even harmonics). The Amp Tube Bias parameter
is very important to this algorithm as it is used to dynamically alter the symmetry, thus
producing even harmonics.
We recommend following this algorithm with any of the speaker algorithms.
01 — Mix
02 — Volume
See the descriptions under the Mix and Volume Parameters, in the beginning of this section.
03 — Amp Preamp Gain
Adjusts the amount of boost or cut applied to the incoming signal. We recommend a gain of 20
dB, since these emulations were optimized for distortion there. Lower preamp gains will result
in less distortion, while higher preamp gains will yield more distortion. For low preamp gain, it
may be desirable to use low tube bias values.
04 — Output Level
This parameter controls the output level of the main amp before the output EQ.
05 — Amp Level Detect Attack
Controls the time it takes for the incoming signal to get to the Amp Tube Bias. Generally the
attack should be short.
06 — Amp Level Detect Release
Sets the amount of time after the incoming signal has ceased for the amp level to shut down.
Generally these times are longer than the attack times.
07 — Amp Tube Bias
For preamp gains approximately 00 dB, this dynamic parameter controls the emphasis of even to
odd harmonics which determines the tone of the amp; mid values emphasize even harmonics
and offer a warmer ("glowing tube") sound, while the highest values may sound like tubes going
bad. Tube bias and preamp gain are independent parameters. For low preamp gain, it may be
desirable to use low tube bias values, because this more closely imitates the operation of a real
amplifier.
08 — Pre-EQ InputLevel Trim
Controls the input level to the pre-amp EQ to eliminate the possibility of clipping boosted
signals.
09 — Pre-EQHighPass Cutoff
Filters out the low frequencies before the preamp. The higher the value, the less low frequencies
pass through.
10 — Pre-EQ Fc
This parameter determines the center frequency of the parametric filter before the preamp.
Higher values have a brighter sound.
ENSONIQ DP/4+ Reference Manual
Section 2 — Algorithms
Range: -48 to +48 dB
Range: 00 to 99
Range: 50µs to 100ms
Range: 1ms to 10.0s
Range: 00 to 99
Range: -18 to +06 dB
Range: 4 to 1000 Hz
Range: 5 to 9999 Hz
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