[Impromptu] problem using two metres

[Andrew Sorensen]

Hi Michele,

You've run into ye oldie play-note vs play trap.  This happens to me  
all the time :)

The duration of play-note is in samples and the duration of play is in  
beats.  So at 120bpm 10000 beats is equal to 5000 seconds - more than  
an hour.  *second*, depending on your hardware, probably equals 44100,  
48000 or 96000 so that's going to be many hours :)

So basically you're killing the audio because you're not releasing any  
of your notes (i.e. polyphony problems).  Change *second* to 1 and  
10000 to 1 and youre code works fine.

If you are using single metre's (i.e. not needing a 2 followed by a 3  
followed by a 2 for example) then you could just use modulo directly.   
Also remember that make-metre is currently "broken" - see Glen's post  
from a couple of days ago.

;; using modulo directly
(define loop
    (lambda (beat)
       (case (modulo beat 8)
             ((0)
              (play piano 60 120 1)
              (play piano 36 120 1))
             ((1 2 3)
              (play piano 36 120 1))
             ((4 5 6 7)
              (play piano 40 120 1)))
       (callback (*metro* (+ beat (* .5 1/2))) 'loop (+ beat 1/2))))

(loop (*metro* 'get-beat 4))






On 11/03/2009, at 9:06 PM, Michele Pasin wrote:

>
> Hi dear Impromptu-fellows,
>
> would you have a go with the code below?
> On my machine the audio constantly disappears after exactly 1 minute
> and 33 seconds (I know, the melody sounds awful, it's because I
> stripped it down to the bare basics for making my point).
>
> If you're wondering what kind of thing I was trying to do... well
> basically I wanted to make a piece by organizing it into various
> 'patches' of 4/4, and call them from a 'master' patch of 8/4 (or 16/4
> or more..).
> It was just an idea, maybe this approach is totally wrong since
> conception! In such case, how would you approach it instead?
>
>
> tx a lot!
>
> mik
>
>
>
>
>
> ===================================================
>
> (au:clear-graph)
>
> (define piano  (au:make-node "aumu" "dls " "appl"))
> (define *mixer* (au:make-node "aumx" "smxr" "appl"))
>
> (au:connect-node piano 0 *mixer* 1)
> (au:connect-node *mixer* 0 *au:output-node* 0)
>
> (au:update-graph)
> (au:print-graph)
>
> ;;; times
>
> (define *metro* (make-metro 120))
> (define metre (make-metre '(4) 1)) ;;  a classic 4/4
> (define metre2 (make-metre '(8) 1))
>
> ;;;;;;;;;
> ;;
> ;;; this crashes the sound output ... I timed it, always after 1:33
>
> (define mel1
>    (lambda (beat)
>       (if (metre beat 1)
>           (play piano 60 60 *second*))
>       (if (metre2 beat 1 )
>           (play piano 48 60 *second*))
>       (if (metre2 beat 1  )
>           (mel2 beat 36))
>       (if (metre2 beat 5  )
>           (mel2 beat 40))
>       (callback (*metro* (+ beat .4)) 'mel1 (+ beat .5))))
>
>
> (define mel2
>    (lambda (beat note)
>       (if #t
>           (play piano note 50 10000))
>       (if (not (metre beat 4))
>           (callback (*metro* (+ beat .4)) 'mel2 (+ beat 1) note))))
>
>
>
> (mel1 (*metro* 'get-beat))
>
>
>
>
>
>
>
>
>
>
>
>
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