Hi all.

I'm running PD-extended 42.5 under OS X on a Macbook Pro late 2009(2,8GHz Core 2 Duo, 4GB Ram @ 1067Mhz) and tried to make some guitar effects. I can't drop the latency under 11ms without getting a really destroyed sound. 11 ms is too much for playing guitar, it gets really annoying after just a short while. But PD is still using only 15% of the CPU. I've searched and searched(the whole day) and tried out pure dyne, but it didn't even produce sound, i don't know where to get drivers for linux and how to install them...that was all much too complicated for me.

Now in the evening i got the idea of installing PD-Vanilla, since it is 43.0. Now guess what! I could set the latency to 1ms. Everything worked fine, tried to just hook the [adc~] to the [dac~]. Then with a delay line, worked like a charm! Timing is so important for playing with delay. Now the bad thing is, that all my nice PD-extended effects don't work anymore

Is there a way to get the latency working right in PD-extended? Or will i have to change everything to work with Vanilla?Why is that even so? Any ideas?

Greetings
Adrian

Have you tried using JackOSX instead of portaudio? I've found it both decreases CPU load and I can get away with a little lower latency.

Also, even if you decide to rework your patches to work in vanilla, don't expect to hang on to the 1 ms of latency. I mean, a block size of 64 is more than a 1 ms. Adding processing beyond [adc~] and [dac~] is going to increase the load, and that 1 ms isn't likely going to cut it.

If i get this right, then the block size is the size of the audio buffer in samples. 1000/44100*64 = 1,45ms. I wonder how big the latency from the rest of the hardware is, because if there is none i could give PD 4-5ms to compute. I guess everything under 5 is fine for guitar. I will definitely try JackOSX, thanks for the tip.

Still i find it very strange that the latency differs so much between vanilla and extended.It's not like there is any more computing going on. Is that just the difference between 42.5 and 43.0 or is it because of the extended?

Oh and something else: At the moment i'm using the internal soundcard from the macbook, which apparently is quite good. But i was thinking about getting a tascam us-122. Do you know, if an external interface will increase or decrease the latency? Or will it be just the same?

The block size is sort of a buffer between the objects themselves. One audio object takes 64 samples at each of its inputs, does it's processing, and outputs 64 samples, which the next object uses for its processing. The latency in the Audio Settings dialog sets the I/O buffer size.

There are some differences with Pd-extended and Pd-vanilla beyond the additional libraries. Hans recently mentioned that Pd-extended uses a more recent version of portaudio. It seems to be helping in some ways, but has also added more latency.

I just did some tests using top to monitor the CPU load using the Test Audio and MIDI patch. I compared the load using Pd-extended 0.43 between the internal sound card and my MBox2 Pro (via Firewire), using both portaudio and Jack. My laptop is a first generation MacBook Pro with a CoreDuo processor.

Portaudio + Built-ins:
Pd: 38%

Portaudio + MBox:
Pd: 25%

Jack + Built-ins:
Pd: 3.9%
jack: 3.6%

Jack + MBox:
Pd: 2.6%
jack: 3.2%

So it seems using an external interface improves CPU load a bit, and using Jack improves it significantly. Interestingly, I also found that when using portaudio, the idle CPU load is quite high initially (around 20-25%). But if you turn DSP on and back off, it drops down to 1-2%. Seems like it's not initializing correctly and needs to be turned on and off to get set right.

I don't know if all this necessarily improves latency, but it couldn't hurt. But I probably should mention that I just realized that I had Jack's buffer size set to 512 samples (about 11ms) and portaudio's set to 20ms. So Jack slaughtered even at half the buffer size.

Hey there!
I've testet the 43.1 beta. It works just like in the 43.0 vanilla release. Seems like that just is some bug that has gotten fixed in 43.x ? I can now set the latency to 1, even 0 (many audio errors...) and now and then an audio error occurs, but no compare to 42.5! Thats cool, since its possible to use pd as a deluxe guitar-effect software now! Patches will follow, i already finished a loop station. Wonder if anyone else has done sth. like that, seems obvious to me...

Thanks for running those tests Maelstorm. If i select "jack" in the settings, pd is just shutting down... But since everything is fine now, i'm too lazy to fix that. Do you think the beta is stable enough for live performances? Any problems with it yet?

You need to download JackOSX to use jack. If you're going to do any big effects patch, I'd recommend using it anyway just for the CPU savings to keep your laptop from burning up on stage.

http://www.jackosx.com/

I don't know if it's live-performance ready yet, but I haven't experienced any crashes Pd-extended 43.1 so far.

Hi! So i bought an Audiointerface(Tascam-US 122) and now it doesn't work anymore. Strangely if i only use the input from the us-122 and the system output, its no problem, but when i use the tascams output and input its all just a crackling mess, no matter how high the latency. But even if i use system output there are crackles now and then also independent from the latency settings. I thought getting an interface would actually improve the performance?

Oh and i installed jack, but can't get it to work, it produces only noise on the tascam. the routing options in Jackpilot are quite cryptic too. theres two system ins and two system outs, no idea what is what there. then there is the same thing with pure data...

Any ideas what i could do?

I've been getting the occasional crackles with portaudio in 0.43.1-extended as well. Looks like the portaudio stuff just still needs some work.

Jack is working great for me, however. Whatever interface you have set up in Jack's preferences refer to the system ins and outs. Pd only shows up in JackPilot when DSP is turned on and jack is selected in the Media menu. The ins and outs of your audio interface should auto-connect to Pd. The only time you have to mess around with the connections in JackPilot is if you want to route audio between apps.

Hi

Will Jack support ever be built into pd-vanilla? Or is that not the point of vanilla?

cheers

Hi I'm new here and i have the same issue!
I have a m-audio profire 610 and a intel duo core 3.00ghz with 3 gb of memory.

I work with other progamas audio sample buffer size to 256 at 44100 and I have no problem. In pd extend this no longer happens because when using these specifications what I get is noise. the minimum at which I can work without having this problem is 100 msec delay corresponding to 4069 buffersize. this makes no sense?