Doepfer A-110 Standard VCO - Manual (Page 10)

A-110 VCO System A - 100 doepfer
10
Fig. 9: exponential FM using the A-110
With FM in the audio range, the ear doesn’t resolve
these octave transitions, but hears the whole sound as
a very full and rather weird composite, with the middle
frequency clearly at odds with the carrier frequency.
Whenever you change pitch using exponential FM, the
inevitable side effect of the change will be an unplan-
ned and un-musical change in the relative pitch of the
components of the sound!
In circumstances where this pitch-shift is not wanted,
you need to use an A-111 High-End VCO instead of
the A-110, because it has the benefit of linear FM,
and can thus avoid this problem.
Tone colour changes using VCO SYNC
Very interesting sounds can be created by syncing
together two VCOs (see p.7), using sub-audio fre-
quency modulation (eg. with an LFO) on the slave
VCO, and a mixer to add to the excitement by subtly
varying the level of each VCO (see Fig. 10).
Try different settings for the slave and master VCO, as
well as varying the FM amount. You’ll be amazed at
the complexity and amount of variation over time of the
overtones created.
Fig. 10: Tone colour changes using VCO SYNC
+ 1
0
- 1
LFO
VCO MIXER VCO
SYNC
CV 2