Pd-list May 2021

pd-list@lists.iem.at

40 participants
46 discussions

plotting spectra/spectrograms with Gem?
by Peter P. 05 May '21

05 May '21

Hi, has anyone tried plotting spectra (magnitudes of STFT frames) in openGL via Gem, possibly using [pix_sig2pix~]? Or spectrograms setting magnitudes line by line to achieve scrolling? thanks for all pointers, P

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Miller Puckette's scofo~ object
by Vinicius Cesar 05 May '21

05 May '21

Hi, all Does anyone know if there's some documentation about scofo~ object, that was implemented by Miller Puckette for score following in pdrp project? I didn't find anything about it. I would like to understand better how it works, and if there's a version newer than 0.2.8. I'm writing about some strategies of score following in my master work, and this would be very helpful. Thanks! Vinícius

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Re: [PD] ignore hidden files from hcs/folder_list
by Dan Wilcox 04 May '21

04 May '21

I'm interested in more info about this behavior. I'm only aware of macOS Finder creating .DS_Store files and temp directories so Spotlight can index and show media playback via Quick Look. Is something creating hidden temp files in the same directory as the audio files themselves or are these in a subdirectory? > On May 4, 2021, at 3:47 PM, pd-list-request(a)lists.iem.at wrote: > > I'm loading a directory of audio files but there are a ton of ._files.wav > that were created by OSX. I've got a bunch of audio sample directories like > this and I could go through and remove all these files, but this software > will also be used by someone on a Mac, so it's better to just ignore this > inconvenient OS behavior if possible. -------- Dan Wilcox @danomatika <http://twitter.com/danomatika> danomatika.com <http://danomatika.com/> robotcowboy.com <http://robotcowboy.com/>

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PdDroidParty MIDI question
by enrike 04 May '21

04 May '21

hi I want to conect a MIDI keyboad to PdDroidParty using a USB to usb type c connector, but I am not sure if I am missing some step. I created a patch that reads notin and sends a message with the note number to a PdDroidParty numberbox. This is working fine in the computer I can see the number changing as I press the MIDI keyboard's keys. Then I install the patch into my phone and run PdDroidParty. The patch opens but it does not seem to connect to the keybord. I read in the docs that "Once you have plugged in your MIDI device and loaded a PdDroidParty path, use the menu to enable access to the device in the software." but which menu is this one? I cannot see or access any menu in the PdDroidParty app. The keyboard works with an app called MIDIkeyboard I installed in my phone. In that one I have to select my keyboard in a menu that pops from a button inside the app in order to connect the keyboard to the app. thanks enrike

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4-point interpolation changes timbre depending on sample rate
by Max 04 May '21

04 May '21

Hi list, the 4-point interpolation in tabread4~ has been a popular topic in the past, going back to at least 2008. [1] A similar issue is in delread4~. In fact a simple resonator changes its timbre quite drastically by just changing the sample rate of the audio interface. Attached is a test patch. The issue becomes audible when choosing an odd delay time and compare the result between an odd and an even sample rate (e.g. 44.1k vs. 48k). This is not good. In fact this is a serious defect. Imagine you want to market a product like a synth plugin (based on libpd) which sounds different depending on if the daw is opened in 44.1 or 48 kHz. Cyrille Henry has coded tabread4c~ with a four-point cubic interpolation in the nusmuk library, but there is no delread4c~ equivalent in nusmuk. Clemens Wegener has coded delreadsinc~ which implements a Whittaker–Shannon interpolation (Sinc function). This implementation does sounds consistent in any sample rate. It also sounds much better at very slow speeds inside a pitch shifter where delread4~ produces serious artefacts. The Sinc function requires a larger padding for the interpolation. There are a couple of questions regarding on how to contribute this to Pd. Vanilla objects are currently: delwrite~ = the sink delread~ = control rate tap delread4~ (vd~) = audio rate tap with a four-point interpolation 1. the code in delwrite~ isn't agnostic towards the interpolation since it already provides the padding for the 4 point interpolation 2. if we add more interpolation methods to delread / tabread, the cleanest way would be to just have one tap object and the interpolation can be changed by a message and argument to it. currently there are implementations for the miller 4pt, cubic 4pt and Sinc. Unfortunately delread4 already carries the 4 from 4-point interpolation in its name, so probably it would be the best to deprecate that and find a new name like varidelay~ or so. [1] Review of tabread4~ threads in the archive https://lists.puredata.info/pipermail/pd-list/2019-06/125391.html [2] https://github.com/chairaudio/pure-data/tree/feature/delreadsinc

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compander-limiter from slop~-help.pd
by Peter P. 04 May '21

04 May '21

Hi list, nice weather today, isn't it? I am trying to understand the [pd compander-limiter] example from slop~'s help patch because I need a 0dBFS brickwall limiter as abstraction without externals. When set to the "no change" parameters, the example will still saturate any signals hotter than 0dBFS. I don't understand what the ratio parameter does, especially its unit and range. It is 100 for dynamic reduction and 200 for expansion in the examples. Furthermore the threshold parameter is 100 for "expansion" and "compression", but 60 for "noise gate"... "Limit" does introduce audible saturation for signals above 0dBFS and I am wondering which paramters could prevent this. Lowering the speed parameter to values smaller than 50 improves this a bit. Is speed an inverse attack time parameter perhaps? And I can't seem to make sense of the boost parameter. Any hints are greatly appreciated! Thanks in advance! Peter

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Pd-list May 2021