[sdiy] Tap Tempo

[D A F]

This might be a dumb idea but could it be done with a phase-locked loop of some kind?  I dont recall them being used to track frequencies in the single digit hertz range but could it be done?

Dave


  ----- Original Message ----- 
  From: Amos 
  To: Tim Parkhurst 
  Cc: D A F ; synth-diy at dropmix.xs4all.nl 
  Sent: Thursday, December 29, 2005 2:48 PM
  Subject: Re: [sdiy] Tap Tempo


  A simple tap-tempo program to feed to a micro is along the lines of:

  begin program on first tap event -
  measure time until second tap event
  measure time between second and third tap events
  average the two measured intervals
  set the new tempo to be one beat = the average interval over the three taps.
  (and reset the counter so that the next tap initiates the cycle again)

  so a-one, a-two, a-one two three and by the downbeat you are groovin' in tempo.

  This is how tap tempo in the moog MuRF is implemented... In practice I find it works a bit better than the simpler method of taking only one interval between any two taps - which is less accurate (or rather requires the user to be more accurate).


  On 12/29/05, Tim Parkhurst <tim.parkhurst at gmail.com> wrote: 
    This did come up a while ago (six months or so, I think), and the general consensus was that a microprocessor-based solution would be simpler and much more accurate. Well, simpler if you know how to program a micro. I think a discrete digital solution ( i.e. not involving a micro) was also proposed, but this would probably end up using a lot more hardware than a processor driven solution. Might be worth checking the archives. 

    And no, not really off-topic at all. :)


    Tim (as simple as it gets) Servo
    -- 
    "Imagination is more important than knowledge." - Albert Einstein 

    ***************************
    On 12/29/05, D A F <polaris30 at ncx.com> wrote: 
      Hi all,

      sorry if this might be a little off-topic, but here goes:

      I was wondering if anyone knows how the more recent effects with "tap tempo" 
      (where the period of an LFO is synched automatically with the taps from a
      foot switch) is implemented?  Does this have to be done with a processor of
      some kind, or could it be done in analog?

      thanks,

      Dave








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