different values at in- and output of a delay-module

Bernd Scheurer

hello forum,

is it possible that the delay module has some kind of memory that influences incoming values? if i understood correctly, the output value should be identical to the input value - just with a time delay.

in this case, the signal at the output of the delay module differs significantly from that at the input.

i'm trying to build a shepard-scale: 8 sine oscillators build a "generator" and 16 generators build one sound module. there are 3 of these modules in total.

each of the modules has different overtone structures for their generators and a time factor (8000ms, 12000ms, 16000ms) which determines when each of the 16 generators starts: generator 1 at time factor * 0, generator 2 at time factor * 1, ... generator 16 at time factor *16).

everything works fine.

the last hurdle is to start the complete construct at a time x, will say in a state in which all oscillators are somewhere in the middle of the scale in order to conceal the otherwise audible structure of the individual parts.

the counter output influences 2 factors of the generator: it adds a calculated offset to the ramp oscillator in round 1 (for starting inside the scale), and it decides whether the delay module is taken into account. the delay should be ignored in round 1 so that all generators are online at the same time.

this works great for the first generator. from the second generator onwards there is a problem. after round 1 it doesn't start again from the beginning, but again towards the end. in the third round there is a reset in the first quarter. after this, everything returns to normal.

i discovered, that from round 1 there is a completely different value at the output of the delay module than at the input - and that is probably the problem. how does this change in value come about and how can it be prevented?

the screenshot shows generator 2 of the first module and the in-and output of the delay-module.

thanks in advance,

bernd

colB

Why should the delay have the same value at input and output?

Some value at the input will only appear at the output after the delay time has passed at which point there might be a different value at the intput. There might be equality if the input is a constant, or if the delay time exactly matches the frequency of some periodic input signal.

Bernd Scheurer

@colB

sorry for the late response to your comment - various other things came up. your comment made me discover a general error in my thinking:

the delay element is extremely unfavorable for starting the individual generators with a time delay because the reset signal gets stuck there. now i have a completely different solution - without any delay - and it works great: https://unterricht.bernd-scheurer.de/shepard-skala2/

thanks and best regards