Dan, the reason I focused on small devices is that RPi is still prone to loose USB connection in cases of short voltage dip. The larger pro-sumer audio interfaces draw a lot of current which adds to the risk of those dreaded brown out moments. That is why I discarded the idea of using my favorite interface, Mackie Onyx Black Jack, in a wearable RPi setup. From the top of my head: the Mackie draws some 500 mA, an iMic ~45 mA and a cheap skype dongle ~10 mA.
Katja On Tue, Oct 10, 2017 at 6:51 PM, Dan Wilcox <[email protected]> wrote: > Katja, that's some good research especially considering the size of those > interfaces. I'm mainly sticking with larger boxes which have XLR and jack > inputs. > > How is the performance overall ala dropouts, latency, etc? > > I ran into issues with RPIs before that simply could not handle asynchronous > with a more pro-sumer USB audio interface, leading to constant dropouts when > running full duplex. I'm mainly using older but very solid Roland boxes > (UA-25 and UA-25EX) which are stereo duplex USB 1.1, fully standard USB > audio compliant, and work with pretty much anything including my iPhone. > > I'm asking as I'd rather not go through the process of setting up a new > system on yet another embedded device and get *less* performance than with > my 500 Mhz wearable 10 years ago. :) > > > On Oct 10, 2017, at 5:49 PM, katja <[email protected]> wrote: > > What I found is, small USB audio dongles don't process low frequencies > well because they use too small capacitors. This can be improved by > DIY soldering. Also some of them do a bad job in noise shaping, > leaving quantization noise in audible range. That is something you > can't improve. Here is a page describing some of my findings: > > http://www.katjaas.nl/audiodongle/audiodongle.html > > Good old Griffin iMic is better than the dongles I tried. But it is > nice to hack a dongle and make it a tiny bit better. Maybe it's time > to design our own audio dongle. > > Katja > > On Tue, Oct 10, 2017 at 3:41 PM, Dan Wilcox <[email protected]> wrote: > > For those of you using RPI 3s with Pd, how is the audio performance using a > standard stereo USB audio interface? > > I'm talking simple, USB 1.1 full duplex at 16 bit, nothing fancy. No special > RPI-only backpack boards or GPIO audio debs, just regular usb audio devices. > > -------- > Dan Wilcox > @danomatika > danomatika.com > robotcowboy.com > > > > > _______________________________________________ > [email protected] mailing list > UNSUBSCRIBE and account-management -> > https://lists.puredata.info/listinfo/pd-list > > > -------- > Dan Wilcox > @danomatika > danomatika.com > robotcowboy.com > > > _______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> https://lists.puredata.info/listinfo/pd-list
