Powerhouse 300
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4:1 DIGITAL REVERBERATION
When live music is played in a concert hall, the sounds of the instruments and vocalists become sustained
and blend into one another. This is due to the sounds being reflected from the walls, ceiling and floor of the
hall and bouncing between these surfaces many times until the "echoes" die away. This effect is called
REVERBERATION.
Many performance venues have poor acoustics; often caused by their internal surfaces not being reflective
to sound. The performance may sound- unnatural and synthetic. Devices for creating artificial "concert hall"
reverberation have been used for many years in the forms of electro-mechanical spring or metal plate based
systems. Apart from being bulky and prone to external noise and vibration, these devices were invariably
noisy, had a poor frequency response, a very limited range of reverb sounds, and in particular an
unconvincing and unnatural sound.
High-speed computer technology has changed all that, allowing acoustic environments to be simulated with
breathtaking accuracy by digital signal processing techniques. In a DIGITAL REVERB, the sound signals
are represented as strings of digital numbers, just like in a compact disc player. A very fast arithmetic
processor continuously performs the millions of calculations every second necessary to synthesise the
many echoes found in natural reverberation. The results of these calculations are then converted back to
analogue sound.
The versatile digital reverberator built in to POWERHOUSE consoles not only provides facilities for
recreating various acoustic environments, but also has some special effects in its 127 program memory.
4:2 THE CONTROLS
1
The TYPE button, and the 8 LEDs above it, are used to select the type of acoustic environment (top
6 LEDs), or various effects (bottom 2 LEDs).
2
The BANK SELECT button. This button is used to toggle between two "banks", indicated by the two
LEDs next to it. When the right LED is lit DARK is selected for the first 6 reverb TYPES. The
selection of "DARK" brings a digital filter into operation, resulting in a more mellow sound. Selecting
DARK also selects the DELAY and SPECIAL EFFECT modes when one of the bottom two TYPE
LEDs is lit.
Selecting the left LED for BRIGHT reproduces the first 6 reverb types without the filter, and is used to
select GATED and REVERSE reverb types.
3
The TIME button, and the 8 LEDs above it, are used to select the decay time of the reverb sound,
the delay time in DELAY mode, or the type of effect in SPECIAL EFFECT mode.
4
The O/LOAD LED indicator gives an impression of the input level and warns of any possible
overload condition.
5
The ON/OFF button allows the reverb to be in-circuit or bypassed. When depressed, the reverb is
in-circuit (ON), and the adjacent LED will light.
Summary of Contents for Powerhouse 300
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