On 08/11/13 23:26, Alexandre Torres Porres wrote:
> Hi there, I was making some tests and saw that the order that you make
> audio connections or create tilde~ objects make a difference, and this
> affects when we're using [s~] / [r~].

yes.

> 
> The idea I had is that no matter what was going on, the sends and
> receives would ALWAYS be in sync with the audio conenction cords,
> meaning there would be no delay whatsoever. But that's not true, so I
> suspect this is some sort of a bug that should be noted.

no.

> 
> check the following patches, they are the same, but one is "ok" (where
> the audio is cancelled) and the other "not ok" (where it isn't). The
> only difference is the order that the objects were created and connected.
> 
> I, for one, would like to live in a Pd world where it'd always be "ok"
> no matter what... cause if we have these delays, it ends up being really
> bad, right?

what you are experiencing is the signal-equivalent of "fan-out" in
message-domain: in msg-world, if you connect a single outlet to multiple
inlets, the order of execution is undefined, so you MUST use trigger.
this is not a problem with DSP-objects, as the order of execution in a
fan-out situation can be evaluated at DSP compile time.
but if you have "implicit connections" (e.g. using [s~]/[r~]), the DSP
graph cannot be evaluated in a well-defined way.

fortunately, Pd offers a solution (just like the [trigger] for
messages): use subpatches connected with dummy inlet~/outlet~s to force
the order of DSP execution.

e.g.

the following might introduce a 1-block-delay between the input to [s~]
and the output from [r~], depending on which part of the DSP-graph is
evaluated first.

[r~ bla]
|
[dac~]

[osc~ 440]
|
[s~ bla]

which can be fixed using subpatches with dummy inlet~/outlet~s:
pd A:
 [inlet~] dummy inlet

 [r~ bla]
 |
 [dac~]

pd B:
  [outlet~] dummy outlet

  [osc~ 440]
  |
  [s~ bla]


and then do:
[pd B]
|
[pd A]

which will guarantee that the contents of [pd A] is executed after [pd B].

fgmasrd
IOhannes

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