On Sun, Nov 11, 2018 at 12:24:05PM -0600, Adam Thompson wrote: > Hello, > > I’d like to use OpenBSD to build a MIDI synthesizer using > SoundFonts, as the OpenBSD MIDI and audio subsystems are remarkably > understandable and sane, compared to everything else out there > today. > � > > However, I’m having difficulty finding a combination of hardware > that is known to be supported. (I tried this a few years ago, but > was unhappy with the results due to the quality of the audio-out > ports on the laptop I used.) > � > > I’ve heard a fair bit here about USB audio not working very well, or > at all, in -stable right now. I’m unsure if this only applies to > XHCI ports or not?
usb audio over xhci doesn't work yet. > Therefore, ideally, I’d like a fanless amd64 architecture system, > that boots from SATA (not eMMC) with either onboard stereo++ audio > (up to and including 7.1ch) *or* a PCI slot for a sound card. > A laptop with really good audio-out would work, too, but I don’t > know of any. > If connecting USB audio to a RPi or BeagleBone Black works well, > then I could try that, too. > � > I intend to use USB MIDI interfaces, as they appear to be supported > and working fine (IIRC). Yes, usb class-compliant MIDI interfaces are expected to work. > > The problem is that, as I browse the list of embedded, fanless > systems I can get from DigiKey, Mouser, et al., all the boards with > audio have HD Audio Codecs that I cannot confirm work with OpenBSD, > and I don’t know enough about how azalia(4) [et a.] works with > random unsupported DACs to drop $250-$500 on something that may or > may not work (i.e. the codec isn’t explicitly supported). > Most (all?) hd-audio codecs should work. The azalia(4) driver handles the hd-audio chipset which interacts with the codec in a standardized way. So the driver doesn't need to care about how codecs work. This is not 100% true as certain vendor (ex Apple) add non-standard features on top of this which break things and require quirks. > > Can anyone make any recommendations for specific hardware that’s > fanless and has working audio-out ports? I've exacly the same project. If you want to build a synth for real-time performance (ie low-latency), I'd suggest using a PCI audio interface. Currently I'm using a M-Audio Audiophile 192k and/or a ESI Julia. I don't have a fanless amd64 board yet, mostly by lazyness and lack of space on my desk. For the MIDI the inputs, I'm using USB MIDI interfaces, but the ones on the above audio interfaces work as well.
