I think my Voyager has a problem with the filter tracking: if I force the filter to oscillate and set the keyboard control to 100%, an octave on the keyboard causes an interval of major sixth in pitch, and to hear an octave interval I have to do a 11th on the keyboard, i.e., apparently the filter is not tracking enough.
I disabled all modulations, both on the panel and in the edit menu.
I asked to the local (Italy) distributor for information, and they say that in their opinion this is normal, but they will do further investigation.
This is my first real synth, so it is possible that I am wrong, but all I know from the analog synths theory tells that the synth has a problem since the filter should track as the VCOs, which are fine.
Do you think I have to send the Voyager back for repair/tuning?
Thanks,
Many thanks for the information, the idea of returning the Voyager for repair made me uncomfortable.
I sent an email asking for the calibration procedure; I wonder what the reason is for the under-tracking.
This has been something of a topic of conversation lately. I checked out a Voyager yesterday and thought that it too was not calibrated properly… until I remembered to set the filter envelope “amount to filter” parameter to zero, which is the 12:00 position for that knob. Remember that the amount to filter is bipolar; you can use the envelope to apply negative or positive modulation to the filter. You can listen to be sure this amount is at zero; as you turn the amount to filter knob counterclockwise the pitch of the self-oscillating filter should fall; if you turn the knob clockwise the pitch will rise. There should be a tiny dead space in the middle where the pitch does not change; this is the zero point for the filter envelope amount control. I found that the filter tracking was impossible to calibrate before I checked this control, and was fine afterwards.
If this adjustment does not improve the filter keyboard tracking, it may need calibration after all.
An important note: the Voyager does not have perfect keyboard pitch tracking. There is no temperature compensation in the filter or in the filter CV processing circuit, and even a very well-calibrated filter will only track accurately across about 2 octaves and a bit… beyond that the tracking will be gradually flat or sharp. The reason that extra circuitry was not added to further linearize the keyboard tracking was probably to keep the cost of the board down to “merely a lot.” The Voyager analog board is already the most expensive one to produce, by far. Nonetheless, tolerable keyboard tracking should be attainable, and if you adjust the filter envelope parameters it may already be better than you think.
filter envelope amount to filter to 0 (12:00), kb. cont. amount to 10, resonance to 10, cutoff to 12:00
dual lowpass mode with filter spacing to 0, fine tuned to get the same note
all mixer inputs off
mod bus: destinations set to other than the filter and amount set to 0
trackpad destinations set to other than the filter
I get a note whose frequency increases about one minor sixth (about 1.6x) per kb. octave; this is quite consistent on all the keyboard, and also if I use the cutoff control to move to higher and lower octaves. It tracked very well, but not on the tempered scale.
Also, changing the ADSR amount to filter, with zero ADR and max Sustain, transpose the tone but does not change the intervals I get, since the constant ADSR output is added to the cutoff control voltage.
I discovered this while creating a patch where I wanted to add a whistle to the VCO notes; I modeled the whistle with noise going through the vcf with high resonance, using the cutoff to stay one octave above the VCO basic tones, but as I moved slightly up and down the whistle was completely out of tune. This was evident even if I used shaped noise and not a pure sine tone.
I finally managed to improve the filter cutoff tracking: since the normal keyboard tracking was not enough, even at max position, I defined a pot mapping with source= pitch, destination=filter cutoff and amount=25%. This increased the cutoff CV enough to get a reasonable filter tracking for about 2 octaves , using the keyboard tracking control for fine tuning.
This trick allowed me to create “whistling” sounds with noise modulated by the filter with high resonance; I also used the spacing control to get another noise peak one octave higher, and both filters tracked reasonably well.