Hi all,

I recently dug out an old Eeepc 701 4G from Asus that I bought second-hand in 2008 - 1-core Intel Celeron inside, with 4GB RAM. I have an audio interface Roland UA22 so that the setup can support realtime audio (Debian 10, RT kernel, jack with RT) with no XRuns and latency <10ms at 44100Hz/128/3. However, obviously, as soon as the CPU is expected to do some calculation, it is much less fun!

In particular I want to use a sampler for some instruments, typically a drumkit connected to MIDI pads, so I wrote a small no-gui Pd patch to load one single wav file in each of 16 clones (for 16 pads) responding to 16 midi notes. I want to keep them in separate clones so that I can assign them to different audio output. Right now it is quite CPU intensive, so I will have to add [switch~] and volume ramps to turn on dsp processing only when the midi note is played and hopefully without clicks.

Further in the workflow, Non-Mixer and Non-Timeline work great for a few tracks, but if I try to record several tracks for several of the drums audio outputs at the same time then the poor laptop is struggling.

TL;DR: Long story short, I'm considering using less fancy mixer and audio sequencer, i.e. command line or Pd patches with no or very basic GUI (no live GUI update as I record for example), BUT I would like to be able to occasionally use some audio effects (reverb, delay and such). Before I get into that, do you guys think that such solution would be bearable for the brave eeepc? Would other languages be more efficient than Pd on this machine?
Or (this is not the right place to ask, but I try anyway) do you know terminal-based utilities that could fulfill this otherwise? I'm thinking of a ncurses mixer similar to alsamixer, or an audio sequencer in the style of CuSE, which would be awesome.

Thanks!

@zigmhount The fact that this computer is a single core doesn't change much for pd (since it's single-thread process). I am running a similar setup (4 samples poly for a drumkit) using a low-latency setup with fx (delay, reverb, disto). I think everything that you need is doable with pd, but yes, you need some optimization (switch~) and monitor the cpu.

Be sure to start pd in realtime too (pd -rt -jack -channels 2 -mididev 1 -alsamidi)

Good luck

@EEight Good to hear, thanks for your answer! I do start pd in realtime.
In the meantime I found meterec for multitrack recording in a terminal, which works pretty well, except that the ncurses interface blinks at every refresh. Instead of looking into fixing this I will probably focus on Pd then

with fx (delay, reverb, disto)

How do you apply the effects in your setup? are they also custom Pd patches, or is it safe to use external ladspa plugins?

single core doesn't change much for pd (since it's single-thread process)

Do you think that it is then preferable to run one single pd process with subpatches instead of several instances of pd? e.g. I already have one for the drumkit, I would probably make a completely separate one for recording and effects, and maybe a separate one for the mixer, but not sure whether the 3 pd processes would compete for CPU time?

@zigmhount I believe [pd~] is made to distribute patches among processor cores.

@zigmhount My FX are both externals and abstractions, I am not using LV2 or ladspa plugins. Since you have a single core, I don't think you should use multiple instances of pd or [pd~]. I might be wrong.

@zigmhount I still use my old T42 at times which is similar in specs, either stripping back your system or installing one which does not start a large number of services by default can greatly help, you should be able to get a full X environment with an insignificant increase in resources, mine is about 60megs of ram and under 1%cpu with a minimal no frills wm. For recording, Ecasound is a command line DAW and works quite well, I believe it also handles midi, do not recall, it does handle both LV2 and LADSPA plugs, there is also the Nama front end for Ecasound, it provides a more adaptable language for controlling Ecasound and an optional minimal gui. SOX is good for recording if you need even less overhead, I do not think it can do multiple tracks, but it can do as many channels which is essentially the same thing. For sequencing, something like Seq24 is very efficient and works well, I have yet to find a console based sequencer that can do better for what it offers, there are a few alright console based trackers, but they tend to be a chore to get up and running as they have not been maintained in some time and are often projects which were never quite finished.

Also make sure to set your CPU governor too performance or just disable and set the speed to max, the old style cpu frequency scaling really kills performance.

@ingox Yeah I've tried to play around with [pd~] before (not very successful so far though), but in this case I'd be considering different patches as different tools that I may or may not want to use together, hence the idea of starting them independently.

@oid Great input, thank you so much! I'll definitely strip down my Bunsenlabs install, but it's already pretty decent out of the box. And I just adjusted the CPU governor as you suggested.
I've fixed Meterec in the meantime but I'll give Nama/Ecasound a try, looks very interesting!