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<p>A DSP loop is when signal connections form a loop. Pd can't look
into objects so it just treats them as black boxes. It's as simple
as that.</p>
<p>After all, in your example with the effect outside your
abstraction you can literally *see* the DSP loop, why are you
surprised? And in your other example with the effect inside your
abstraction you don't get a DSP loop because, well, there's is no
DSP loop.</p>
<p>I see where you're coming from. In the analog world your two
examples are indeed equivalent, but in Pd they are *not*.<br>
</p>
<p>Christof<br>
</p>
<div class="moz-cite-prefix">On 25.02.2020 23:46, Christof Ressi
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:98f86c80-50e6-96b5-1469-fd1c1a90a5f9@christofressi.com">
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<p> </p>
<blockquote type="cite">especially because of additional potential
delay of inlet~/outlet~.</blockquote>
inlet~/outlet~ does *not* add a delay (unless when going to a
larger blocksize).
<p> </p>
<blockquote type="cite">
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex">
<div>But you're using [r~] and [s~] which is not the same as
direct signal connections. The former can act like a short
delay line. Please read
"3.audio.examples/G05.execution.order".</div>
</blockquote>
<div><br>
</div>
Christof, Yes! Exactly!</blockquote>
I think you misunderstood. With "former" I meant [r~]/[s~].
[inlet~]/[outlet~] does not add a delay.<br>
<p> </p>
<blockquote type="cite">Also, believe me, r~/s~ has nothing to do
with it. </blockquote>
Believe me, it certainly has. Can you finally share a minimal test
patch, please? I would like to see an actual patch where you get
an unexpected DSP loop error.<br>
<p>Christof<br>
</p>
<div class="moz-cite-prefix">On 25.02.2020 23:40, William Huston
wrote:<br>
</div>
<blockquote type="cite"
cite="mid:CAAV8_8n7Eg5dsA_ERGwrVWYJ47pyM3ZdWvatTXiiDOYFboOj9w@mail.gmail.com">
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<div dir="ltr">
<div dir="ltr" class="gmail_attr">On Tue, Feb 25, 2020 at 6:14
AM Christof Ressi <<a
href="mailto:info@christofressi.com"
moz-do-not-send="true">info@christofressi.com</a>>
wrote:<br>
</div>
<div class="gmail_quote">
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div>
<p>@Dan<br>
</p>
<blockquote type="cite">As far as I recall, going
between abstraction to parent patch via inlet~/outlet~
introduces a block delay, hence no error</blockquote>
</div>
</blockquote>
<div>Dan, correction-- that is the exact circumstance where
I *am* getting the error. <br>
</div>
<div>So now I think you are beginning to see why I think
it's unexpected,</div>
<div>especially because of additional potential delay of
inlet~/outlet~.</div>
<br>
<div>Dan also wrote:</div>
<div>> As the error says, you shouldn't create a direct
feedback loop with signal cords. <br>
</div>
<div><br>
</div>
<div>Let me try to explain again:</div>
<div><br>
</div>
<div><span style="background-color:rgb(255,255,0)"><b>I have
taken a WORKING CIRCUIT--</b></span></div>
<div><b> </b>
<div>(a simple stereo delay circuit, with cris-cross L/R
feedback <br>
</div>
<div>implemented with [delwrite~] + [vd~]) <br>
</div>
<div><b><span style="background-color:rgb(255,255,0)">--
which DOES NOT produce a "DSP Loop Error", </span><br>
</b></div>
<div><b>pulled a Null (straight-wire) Filter <br>
</b></div>
<div><b>(which had been installed in the feedback path)<br>
</b></div>
<div><b>and moved it externally to the abstraction</b></div>
<div><b>(up to the parent patch), via outlet~/inlet~,</b></div>
<div><b>which, if anything ADDS additional block delays, <br>
</b></div>
<div><b>yet this produces "DSP Loop Error". <br>
</b></div>
<div><b><br>
</b></div>
<div><b>Clearly (the way I see it) <br>
</b></div>
<div><b>the logic behind detecting "DSP Loop Error"
condition<br>
</b></div>
<div><b>has a bug.</b></div>
<br>
<div><b>I believe this is a false error,</b></div>
<div><b>because as I have stated--</b></div>
<div><b>the circuit HAD been working!</b></div>
<div><b><br>
</b></div>
<div><b>All I did was add the potential for additional</b></div>
<div><b>blocks of delay on the feedback path. <br>
</b></div>
</div>
<div><br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div>But you're using [r~] and [s~] which is not the same
as direct signal connections. The former can act like a
short delay line. Please read
"3.audio.examples/G05.execution.order".</div>
</blockquote>
<div><br>
</div>
<div>Christof, Yes! Exactly!<br>
</div>
<div>Added delay should REDUCE the chance of a "DSP Loop
Detected"!</div>
<div><br>
</div>
<div>Also, believe me, r~/s~ has nothing to do with it. <br>
</div>
<div>My original patch was extremely ugly, due to
criss-crossed feedback.</div>
<div>I only implemented with r~/s~ to clean up the patch to
share. <br>
</div>
<div><br>
</div>
<div>Thanks everyone!</div>
<div>BH<br>
</div>
<div><br>
</div>
<div><br>
<br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<div><br>
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<div><br>
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<div><br>
</div>
<div><br>
</div>
<div><br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px 0px
0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div>
<p>Christof<br>
</p>
<div>On 25.02.2020 11:42, Dan Wilcox wrote:<br>
</div>
<blockquote type="cite"> As far as I recall, going
between abstraction to parent patch via inlet~/outlet~
introduces a block delay, hence no error
<div><br>
</div>
<div>
<blockquote type="cite">
<div dir="auto">
<div dir="auto">
<div dir="auto">Third patch is like the
second, only the effect has been moved out
of the abstraction, and into the parent
patch. ONLY HERE do I get the DSP loop
error. </div>
</div>
</div>
</blockquote>
<div><br>
</div>
Signal loop in a single patch without abstractions =
error. Pd has no way to read and write to the same
signal buffer in the patch at the same time
*without* some tiny delay.</div>
<div><br>
</div>
<div>
<blockquote type="cite">
<div dir="auto">
<div dir="auto">
<div dir="auto"><b
style="font-family:sans-serif">The point
is the last two patches have (or should
have) an identical graph! </b></div>
</div>
</div>
</blockquote>
<br>
</div>
<div>At the lower level, they don't. What happens if
you put part of the path inside a subpath which uses
inlet~/outlet~?</div>
<div><br>
</div>
<div>
<div>
<blockquote type="cite">
<div>On Feb 25, 2020, at 11:36 AM, William
Huston <<a
href="mailto:williamahuston@gmail.com"
target="_blank" moz-do-not-send="true">williamahuston@gmail.com</a>>
wrote:</div>
<br>
<div>
<div dir="auto">
<div dir="auto">
<div dir="auto">First abstraction, simple
stereo delay: 2 delay lines, variable
feedback L->R, R->L.</div>
<div dir="auto"> This <b>works</b>, no
DSP loop error. <br>
</div>
<div dir="auto"><br>
</div>
<div dir="auto">Second abstraction
contains an effect in the feedback path.
(in my simple example, it's just a null
wire: In-L passes to Out-L, etc). Again
this <b>works</b>, no DSP error. </div>
<div dir="auto"><br>
</div>
<div dir="auto">Third patch is like the
second, only the effect has been moved
out of the abstraction, and into the
parent patch. ONLY HERE do I get the DSP
loop error. </div>
<div dir="auto"><br>
</div>
<div dir="auto"><b
style="font-family:sans-serif">The
point is the last two patches have (or
should have) an identical graph! </b><br>
</div>
<div dir="auto"><b
style="font-family:sans-serif"><br>
</b></div>
<div dir="auto"><font face="sans-serif">It
really seems like a bug to me. </font></div>
<div dir="auto"><span
style="font-family:sans-serif"><br>
</span></div>
<div dir="auto"><span
style="font-family:sans-serif">I'll
upload a test patch a little later. </span></div>
<div dir="auto"><span
style="font-family:sans-serif"><br>
</span></div>
<div dir="auto"><font face="sans-serif">Thanks, </font></div>
<div dir="auto"><font face="sans-serif">BH</font></div>
</div>
</div>
</div>
</blockquote>
</div>
<br>
<div>
<div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">--------</div>
<div
style="color:rgb(0,0,0);font-family:Helvetica;font-size:12px;font-style:normal;font-variant-caps:normal;font-weight:normal;letter-spacing:normal;text-align:start;text-indent:0px;text-transform:none;white-space:normal;word-spacing:0px">Dan
Wilcox</div>
<div
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href="http://twitter.com/danomatika"
target="_blank" moz-do-not-send="true">@danomatika</a></div>
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href="http://danomatika.com" target="_blank"
moz-do-not-send="true">danomatika.com</a></div>
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href="http://robotcowboy.com" target="_blank"
moz-do-not-send="true">robotcowboy.com</a></div>
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