dsp clock rate
control
PHASE/POLARITY
When discussing the impact of feedback, there
is often a distinction between positive and
negative feedback, but this distinction only
makes sense for memoryless devices. When
there is any delay involved, various spectral
parts of the signal are shifted in phase differ-
ently; hence the whole is no longer in phase
with the original, and its inverse is no longer
anti-phase. Deva features manual phase
switches (which actually change the polarity)
feedback effect. Neither option is truly posi-
tive or negative feedback; thus, cancellation
and reinforcement of certain frequencies may
be unpredictable.
TILT FILTER
The treb/bass-
tion for timbre control using only one potenti-
ometer (and CV input). The middle position of
the slider suggests a neutral setting; however,
-
tenuates at both ends of the signal spectrum
while adding analog warmth.
Setting the slider above the middle causes the
sound thinner. For example, with a delay ef-
fect, this results in brighter echoes (note: the
A similar effect is obtained by feeding a posi-
tive voltage (up to +5V) to the CV input.
Setting the slider below the middle causes the
thus introducing darker coloration to the sig-
nal returned to Timiszoara. For example, with
a delay effect, this results in darker echos.
A similar effect is obtained by providing a neg-
ative voltage (down to -5V).
DSP CLOCK CONTROL
By default, the Spin FV-1 chip at the heart of
Timiszoara operates with a system clock of
32768Hz that determines both the sampling
rate of the signals (and bandwidth of 16kHz),
the computing speed, and the algorithms’
timing. Since the internal memory is precise-
ly 32768 words, this results in a maximum of
1 second of total delay.
Deva offers manual and voltage-controlled
over- and underclocking of the DSP chip from
2x down to 1/16 of the normal speed. With
the miniature switch in the variable posi-
tion, setting the central clock rate slider at
maximum changes the clock to over 64kHz,
signaled by the LED turning red. A CV of 5V
plugged into the jack above it achieves a sim-
ilar effect. Setting the slider at the minimum
position changes the sampling frequency to
2kHz, shown by a green LED. Using a negative
CV has a similar effect.
It is important to remember that while the
sampling and processing rate of the signal
changes with the clock, the bandwidth of the
do not change. Therefore, with low-frequency
sampling, aliasing artifacts are very audible.
For example, at the lowest speed, the effective
bandwidth is only 1kHz, so all spectral com-
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