Hi - I've been doing some more tests on this and have another kernel for people to try (Test Kernel #2)
Please also update to USB Audio Output 0.2 as this includes something to improve 96k playback. I should point out what the different kernels do and what is leading me to look at this. From tests with my dac it appears that there is some form of limitation with the USB hardware in Touch related to the "Transaction Translator". This is part of the usb implementation which supports usb 1.0/1.1 devices connected to a usb 2.0 host. The specific limitation is that it does not appear to support output and input iso packets (sitd) in the same 1ms timeslot on the usb bus. The two kernels work round this in different ways and so one may be appropriate to you: Kernel #1 - supports up to 44/48k sampling rates by restricting output packets to every other 1ms frame, thus allowing async input packets on the interviening frames. This relies on the async implementation in the dac supporting data arriving every other frame it asked for. It works with my Audiolab dac (with usb firmware by Lakewest audio) and I've verified with the author of that firmware that it should work. However it is breaking the requested parameters and so does not looks to work with several other dacs. This is probably the reason for the other test cases above failing. Kernel #2 - supports up to 96k sampling rate by not changing the usb protocol. (Its a very minor modification of the default kernel to avoid the "not enough bandwidth message" seen with some usb devices) However it is intended to be used with an external usb high speed hub. In this configuration, the usb 1.0 to 2.0 translation is done by the external hub rather than the silicon within Touch and this seems to bypass the problem hardware. It works for me with the hub in my monitor - it is worth people testing with any "high speed" hub. Note there can be problem with rebooting the Touch, hub and dac in the right order so the Touch sees the dac, but once working seems to work ok at all sampling rates upto 96k for me. Thanks to Dominik of Lakewest for suggesting the hub approach. Please test and post here if these work better for you.... -- Triode ------------------------------------------------------------------------ Triode's Profile: http://forums.slimdevices.com/member.php?userid=17 View this thread: http://forums.slimdevices.com/showthread.php?t=93310 _______________________________________________ Touch mailing list Touch@lists.slimdevices.com http://lists.slimdevices.com/mailman/listinfo/touch
