ULTRACOUSTIC ACX450/ACX900/ACX1800
4. SOUND PROCESSING
The ULTRACOUSTIC offers many options for sound processing. The ACX1800 includes, for example, an FBQ equalizer, a multi- effects unit and a compressor. The various processing options are explained in this chapter.
4.1 FBQ equalizer
A graphic equalizer with FBQ spectrum analyzer is available for sound adjustment and correction. If the sliding controllers are in neutral position (0), the signal is not modified.
sTo boost the frequency range, move the respective sliding controller up.
sTo dampen the range, move the sliding controller down.
sPress the FBQ switch 
to activate the FBQ display.
FBQ function: Each controller is equipped with a LED indicating the level of the associated frequency range of the controller by means of its brightness. This assists you in identifying the controller that must be used to edit the sound. If the sound is for example too dull or too droning, one of the LEDs is probably very bright, indicating the sliding controller that should be moved down to reduce the bass level. On the other hand, you can quickly identify frequency ranges whose level is too low (LED barely lit) to increase it.
+To emphasize certain frequency ranges, it might not be necessary to raise these, but to lower the levels of the other frequencies by moving the respective sliding controllers down. This approach prevents excessively high internal signal levels, thus retaining valuable dynamic reserves (“headroom”).
4.2 Digital effects processor
One of the key features of your ULTRACOUSTIC are the two
sTo switch effects on or off, press the IN/OUT switch 
at the ULTRACOUSTIC or at the foot switch.
sTurn the FX SELECT controller 
to select a program. The effects are described in the following overview:
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| Chamber | Decay | ||
| Room | Decay | ||
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| Hall | Decay | ||
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| Concert | Decay | ||
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| Chorus | Depth | |
| Flanger | Depth | ||
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| Phaser | Speed | ||
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| Tremolo | Speed | |
| Chorus / Delay 400 ms | Delay Level | ||
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| Flanger / Delay 400 ms | Delay Level | ||
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| Chorus / Delay 300 ms | Delay Level | ||
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| Flanger / Delay 300 ms | Delay Level | |
| Delay 80 ms | Feedback | ||
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| Delay 300 ms | Feedback | |
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| Delay 400 ms | Feedback | ||
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| Delay 500 ms | Feedback | |
Table 4.1: Effects programs
sUse the FX LEVEL controller 
to make the effect audible.
sEdit the effect using the PARAMETER controller 
(only in ACX1800).
The reverb presets are effects that imitate the reverberation of various large rooms. Use the PARAMETER controller to adjust the reverberation time (decay).
1CHAMBER simulates the typical characteristics of a studio. This effect is useful in cases where you need unobtrusive reverb to liven up the signal.
2ROOM: Reverberation typical for rooms of medium size, with clearly audible reverb from walls.
3HALL: Simulation of a lively large hall with considerable echo.
4CONCERT simulates the prolonged reverb in a large concert hall.
This group includes four modulation effects that are generated in different ways. For each effect, you can adjust the depth and speed of the modulation.
5CHORUS give guitar signals more depth and width. This is achieved by means of a modulated delay of the input signal.
6FLANGER: Popular guitar effect achieved by constant modulation of the tone pitch.
7PHASER: The phase effect is similar to the flange, but somewhat subtler. It is achieved by superimposing a
8TREMOLO: Intensive variation of the volume at a preset rate.
This group includes a number of dual effects where for example a chorus or flanger effect is combined with a delay. In the ACX1800, you can adjust the volume of the delay effect.
9CHORUS/DELAY with a delay of 400 ms.
10FLANGER/DELAY with a long delay (400 ms)
11CHORUS/DELAY with a short delay (300 ms).
12FLANGER/DELAY with a delay of 300 ms.
In this group you find delay effects with different delay times. The “Feedback” parameter determines the number of repeats.
13Short DELAY of 80 milliseconds (ms).
14Medium DELAY of 300 ms.
15DELAY of 400 ms.
16Long DELAY of 500 ms.
8 | 4. SOUND PROCESSING |