First abstraction, simple stereo delay: 2 delay lines, variable feedback L->R, R->L. This *works*, no DSP loop error.
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 *works*, no DSP error. 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. *The point is the last two patches have (or should have) an identical graph! * It really seems like a bug to me. I'll upload a test patch a little later. Thanks, BH On Tue, Feb 25, 2020, 5:22 AM Dan Wilcox <[email protected]> wrote: > As the error says, you shouldn't create a direct feedback loop with signal > cords. > > I usually use [throw~] and [catch~] for send/receive busses via the rjlib > [c_bus], [c_tobus], & [c_frombus] wrappers: https://github.com/rjdj/rjlib > > Additionally, I've made stereo versions ([c_bus2], [c_tobus2], > [c_frombus2]) in my own rc-patches: > https://github.com/danomatika/rc-patches > > I suppose we are introducing (tiny) relays with every step, but in > practice I have never perceived it. Then again, most of what I do does not > relay on "sub-2ms" latency. For a large project at work, we have a signal > path with 64 channels using throw~/catch~ like: input/soundfile channel -> > spatialization -> virtual speaker -> output. > > On Feb 25, 2020, at 9:50 AM, [email protected] wrote: > > Message: 2 > Date: Tue, 25 Feb 2020 03:50:18 -0500 > From: William Huston <[email protected]> > To: Pd-List <[email protected]> > Subject: [PD] Delay circuit feedback DSP error-- only when signal path > leaves abstraction > Message-ID: > <CAAV8_8=ui0ov-hi8jboxm4mdp_+u8atbz+uqqnqh9r1bodz...@mail.gmail.com> > Content-Type: text/plain; charset="utf-8" > > Hi, I've built a classic stereo delay using [delwrite~] and [vd~], and L/R > crossed feedback. This works! > > Now, I want to insert an effect into the feedback path. (many possibilities > here: add some bitcrush, so each repeat gradually becomes more > distorted.... or a [hilbert~] type pitch shift, which might create > something like Shepard tones, etc). > > *This works when everything is within a single patch or abstraction. * > > However, when I try to allow the effect to be external to the abstraction > (like a SEND/RETURN insert on a mixer), when I try to complete the circuit, > I get "DSP loop detected". > > > -------- > Dan Wilcox > @danomatika <http://twitter.com/danomatika> > danomatika.com > robotcowboy.com > > > >
_______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> https://lists.puredata.info/listinfo/pd-list
