Q: El Capitan USB audio problems.

I had been using a Sabre-based DAC (http://www.amazon.com/gp/product/B00AOH5JTQ?psc=1&redirect=true&ref_=od_aui_deta ilpages00) in OSX 10.11.1 without issue. I opened Sound Prefs to check a setting, now the DAC doesn't work anymore. Tries to connect, burps, and goes back to external speakers, over and over. Clearly, the problem is not the DAC, it's Apple's brittle, ridiculous implementation.

I despise what has become of Apple Software. Mac user since 1985. They should be ashamed. Jobs must be spinning in his grave.

Thank you! Looks like the R16 & R24 are the only remaining products still awaiting driver updates for El Capitan. Zoom's compatibility page can be found here... https://www.zoom.co.jp/news/mac-os-x-el-capitan

Well, solved my own problem. Plugged the DAC into a USB port on my Dell monitor, it works just fine. Sounds great. So, lesson learned. Want your stuff to work? Don't plug it into an Apple product.

Bose Companion 5 now working.

Many Thanks to Marco29dpt with the solution regarding shutting down the mac, disconnecting the power lead and holding down the power button for 5 sec (or more).

This worked for me.

Be careful sometimes when the mac is waking up he loose the usb connection in rare occurence

Waiting for a el capitan patch for USB.....

Marco29dpt

Double post, sorry.

Haven't plugged in my Nuforce DAC 2 for a week or so. Now I'm getting IOUSBHostInterface in the system sound preferences output options.

I use Audio Hijack to 'sweeten' my audio output to an amp. I have to restart the app to select IOUSBHostInterface, because it looks for the Nuforce and wigs out. This is 'working,' but it is definitely a workaround and needs attention from Apple.

There may be issues for drivers for specific devices, but the Nuforce is not one of them. It only depends on the OS X USB software to do its thing.

Jimmy, the serious flaw with your reasoning is that these are generic USB DAC devices.  There are no "special" drivers for them.  It's all part of USB specs.  If things don't work, it's OS fault.  To put it another way, there are no special mouse, keyboard, webcam, mass storage, etc, etc drivers either.  They are all well defined in USB specs and (generic) drivers are *always* provided by the OS manufacturer, not by the hardware manufacturer.  Even if "NuForce and Apple engineers talk to each other to find where the issue is", it will be up to Apple to release the fix for the driver.  Because they wrote it, and whatever changes to it they made in the latest release, they broke things.

In the old dark ages, there were no generic standards for these devices, and each manufacturer provided their "special" drivers that worked only with their device.  This always boiled down to:

1. Device doesn't work on OS X, period.  Windows only.
2. After you upgrade OS, it was a gamble if manufacturer will release new drivers or you'd have to throw perfectly good piece of hardware into garbage bin.

Sure.  If you want to go back to dark ages, feel free to pull your argument that it is up to hardware manufacturers to supply "special" drivers for generic devices.

@Alex

I believe that Apple's argument is that these 'generic devices' do not necessarily follow the USB spec as well as they should, and that Apple has applied stricter enforcement of some parts of the specification. That is where the issues are rooted.  I'll see if I can find a link to the source of that statement.

I've never written a USB driver before (though I added a scanner to SANE once), so I do not know if the above is entirely true, or just 'true-ish'.

Last year I built a portable sound system. The embedded USB DAC based on a TE7022 (translates USB to a bit stream) and CS4398 (DAC chip) worked really well. With EC not anymore. Now I don't know what to do. Is this going to be fixed? If not, I can replace it, which will of course cost money. But by what board, by what chipset?
I cannot find any information by Apple about demands on compatibility, on chipsets that do or don't work. Does anybody know whether such information is available?

Coming closer a little bit:

kernel[0]: USB Sound assertion in /BuildRoot/Library/Caches/com.apple.xbs/Sources/AppleUSBAudio/AppleUSBAudio-301.52/AppleUSBAudioStream.cpp at line 4737

com.apple.WebKit.Plugin.64[7118]: [12:13:52.081] <<<< AVCaptureHALDevice >>>> -[AVCaptureHALDevice _removePropertyListeners]: Removing alive observer for device <AVCaptureHALDevice: 0x7fd5ab242b20 [DigiHug Track 0/1 &SPDIF][AppleUSBAudioEngine:Tenor Electronics:DigiHug USB Audio:fd120000:2,3]> failed (560947818)

Some theorizing:

- I suspect that the issues occur with some streaming chips more than that the actual DAC chips themselves are a factor. The streaming chip sits in front of the DAC chip and converts the USB signal into the I2S protocol which feeds into the DAC chip.

- There are two USB protocols:  USB audio class 1 and USB audio class 2.

- My DAC board uses a Tenor chip with two input and two output channels. However only the output channels are in use. When I look into the audio MIDI configuration program I see the input channels also. Could that create a problem or is it just transporting a lot of zeros?
Reading through the documentation of the chip not all combinations of bit rates and channels in use are possible. This  because of the limited bandwidth of USB. So if the OS tries to use all channels simultaneously, things will go wrong.

It would be handy to get some grip on what devices do and what devices don't work. Especially the streaming chips that are in those devices. Unfortunately these are never mentioned.

Googling on 'AppleUSBAudio-301' reveals a lot of issues, not always on the same line. Would love to see that code.

I have the Wadia 151 PowerDAC mini, which worked perfectly in Yosemite.  When I loaded El Capitan it stopped working, but the solution was simply to open up the "sound" icon in system preferences, which had reverted to the internal speakers, which seems to be the default on the MacBook Air.  The Wadia DAC was still there and just needed to be selected.  Once I did that everything worked perfectly again.

After 10.11.2 update....

No, it hasn't been fixed yet. Now music plays for about 1 second on the DAC then it disconnects and switches back to another available audio device. After a few seconds it reconnects, plays again for a second and so it goes on and on.

Tried every possible setting in the audio/midi settings, makes no difference. Even if you mute all channels the reconnecting cycle continues.

Some other issues on the usb bus seem to have been fixed. I can now use keychain access and secure notes while my Wacom is connected. Previously I had to disconnect the tablet first.

This is ridiculous.   It's been an issue since the first beta version of El Crapitan and here we are 10.11.2 and still no fix for a universal USB device, what a disappointment.

Please Apple stop it !!!!! Nothing change after 10.11.2. The same issue with Airplay who doesn't work with Audivarna by exemple.