Block Diagram - Korg SDD-3000 Owner's Manual

samples that are stored before the sound is 'read' out again. This is shown on the LED Display and can be varied using
the UP & DOWN buttons. The basic delay time can then be varied by changing the sample rate. This is how the
Modulation Section changes the delay time.
The Modulation section in the SDD3000 includes a low frequency oscillator (LFD) with two waveforms, a Random
Voltage source and an Envelope Follower. Additional control sources may be connected using the Delay Mod CV
input. All of these modulation possibilities allow a great many effects to be produced.
Effect Balance
The balance control allows the output signal mix to be adjusted from direct (unprocessed signal only, to delayed signal
only, or anywhere in between. It is basically used to control how prominent the effect will be. At short delay times
(under about 50 milliseconds), mixing the direct and delayed signals will create a series of many narrow peaks and
valleys in the frequency response through a process of phase cancellation. This series of peaks and valleys can create
flanging effects (under about 20 milliseconds), chorusing or doubling effects (20 - 50 milliseconds), or a 'fixed
equalizer' effect when no modulation is used. These peaks and valleys are most apparent when the LEVEL BALANCE
control is set around 5.
Regeneration
Regeneration or feedback is probably the most mysterious sounding part of a delay line, but it's actually fairly simple.
All it involves is taking part of the signal coming out of the delay line and feeding it back into the input to go through
the delay line again. At longer delays, adding FEEDBACK simply in creases the number of repeats or echoes from 1
(with FEEDBACK = 0), to 2 or more (FEEDBACK = 1-2), to 'runaway' oscillation (FEEDBACK over about 7).
In fact, the HOLD button is just a special kind of Feedback which will 'recycle' the sound indefinitely. without loosing
audio quality. Even without HOLD, however, the SDD-3000 will maintain excellent signal quality after a large number
of repeats. At shorter delays, the 'repeats' from feedback are so close together that you really can't hear them as repeats.
Instead, they emphasize the 'peaks and valleys' character of the delayed signal and make it more resonant, or 'peakier',
very much like a filter (in fact, a delay line used this way is a filter, although a very special kind). The peaks and
valleys produced by a delay line occur at harmonic frequencies, just like the overtone series of a musical note, with the
'fundamental' peak being determined by the actual delay time setting. Normally, this isn't particularly audible, but when
feedback is added, it becomes much more pronounced and can be used to make cymbals and other rich but unpitched
sounds take on a definite pitched character. There are far more peaks arid valleys in the upper part of the frequency
response than in the lower part, just as overtones are packed more and more closely as you go up in the harmonic series.
Adding FEEDBACK with short delays normally emphasizes higher frequencies more than lower ones, and this results
in sounds that seem harder, more metallic, brittle and/or spacey. However, the Korg Digital Delay provides a pair of
switcheable HIGH and LOW filters which can be used to tailor the response of the Feedback. They can be used to
produce emphasized chorus and doubling effects that are warm and rounded, flanges that are exceptionally metallic or
unearthly, 'natural' echoes where the highs die out first and the lows linger, and a wide variety of other pleasing sounds
and unique special effects.

BLOCK DIAGRAM

Click here to have a full view of the block diagram.