[sdiy] Adding Tap Tempo to an LFO

[Blandon Ray]

On 7/18/05, ASSI <Stromeko at compuserve.de> wrote:
> On Montag, 18. Juli 2005 17:11, Paul Perry wrote:
> > Unless a LFO is digitally generated, it is pretty difficult to
> > get tap tempo going.
>
> Not so. The LFO is presumably voltage controlled and you can also
> generate a downward ramp signal that can be synchronized to the tap?
> Just S&H the ramp at each tap before you reset it and make a moving
> average of the last few taps. Synchronize the LFO too if you need it.
> The rest involves some scaling of the control voltages and figuring out
> how to keep the CV constant when there is no tapping.

This sounds like it might work, but I'd expect it to have limited
usefulness, musically speaking. Because if you don't know the tempo,
it's not easy to tell what the initial frequency of the downward ramp
signal should be, so between that and taking the moving average it'll
be several cycles before you have a synchronized output

I'm working on something vaguely similar, and I came to the conclusion
that I'd have to read the tempo in the digital domain and use a DAC to
generate a downward ramp voltage, which can then be used to run the
core of a traditional analog LFO.

Blandon