Forums > Voice of Saturn Kits > Viewing Thread
I’m posting segments from some emails we had with John about the gate trigger…
In the interest of making a simple sequencer, the gate doesn’t trigger like a typical sequencer does… there aren’t any controls for the gate time, for instance. The gate output is basically all of the individual step outputs tied together, so unless a step is turned off, the gate will always stay on. The CV, however, drops to zero when a step is off, and this gives the effect of a note being off.
from John’s emails:
“Thanks guys, I got it working by making the change. What a great, simple little sequencer!
How hard would it be to add a Gate Time pot to this?
Also, one thing I’m noticing is when a step is turned off there is a bit of a thump and a click when the sequence passes that step. Maybe this is normal due to the continuous gate signal.”
scott: “probably the CV dropping to zero on off steps…”
John: “I think I just need to play around with it a bit more. I’m noticing things that don’t seem to happen with other sequencers (at least ones that I have used). Also, keep in mind I’ve only tested this so far with my Pro One. For example, an 8 step sequence with all steps activated seems to render the envelopes useless (Sustain works as overall volume, no matter what the Attack, Decay is set to it does not affect the envelope as expected). I found the thump culprit – if the Release is set relatively long a thump at a much lower pitch is heard just before it switches to the next step. However, when every other step is activated the envelopes on the synth works as expected (and there is no thump as long as the Release is not too long).
x x x x x x x x ---> each note runs into the other (100% gate time), envelopes have no effect on shaping the sound (not retriggering) x 0 x 0 x 0 x 0 ---> alternating on/off allows the envelopes to trigger properly x x x 0 x 0 x x ---> step 2 and 7 do not sound at all unless the Sustain is up very high. Attack/Decay have no effect on 2 and 7.
Sustain seems to be the key issue that’s why I was wondering if there was a way to control the gate signal sent out by the sequencer, this would solve the problem (I think). Does this make sense at all?”
Scott: I think some sort of 555 astable circuit (basically a pulse width modifier) could be used to partially achieve this effect. Keeping the CV from dropping low on an off step would take some more work, some sort of sample and hold. We’d love to hear other ideas on any simple ways to improve the design.