Flexible table playback by index, concept?

#1

Hello people,

I would like to play samples forward/backward with variable speed. The common way would be using an "lfo/saw lin" object controlling a "table/read interp" object, while a value from 0 to 64 equals the playback position from 0 to 100%. This way it works.

Now i would like to control the playback position not with a ramp up signal like the lfo, but with a index integer I receive from a rotary enocder (600 pulses/rev).
In the example patch I just receive the trigger and count up. Normally it would reset when leaving minimum or maximum treshold.

The problem is, that when receiving a pulse (count up) a short crackeling noise is played whenever I turn the encoder and increase the counter by one. Nothing more. So it seems that the inerpolation here is misunderstood or used the wrong way by me and does not deliver a stream of fractional numbers like the "lfo/saw lin"-object.

As I understand, when playing a 48kHz sample, for normal speed the number at the input of the "table/read interp"-object would have to rise by 48.000 per second.

In PureData I would use a [line~]-object, together with the ramp-up time. So something like this would be needed?

Many Greetings & Thank you for helping,
himi

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#2

I also love Pure data and have been missing something like line~ a few times.

Anyway, for the crackling issue, have you tried using conv/NONinterp?

#3

Not sure it will work here (my experience with tables is still limited) but I’ve had good luck with using a smooth object to get rid of clicks when adjusting table reads.

#4

@spacelordmother thanks, that was exactly what I was looking for. It does a similar thing as pd's [line~], interpolates between two values over time at k-rate.

I did like this now. Basically it lets you play samples with the encoder in the way you do it with a CD-DJ controller. Maybe it helps someone else. If you have any suggestions to improve or simplify it please tell me.

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The hardest parts was (and still is) to get an idea of the fixed point number computation and all the different value ranges ranges. Before I only used puredata which uses floating point computation and you don't have to worry about anything. This made me a little mad in the beginning, but now I think it all has its deeper purpose and I'm learning something new about bit-shifting and computer math.

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