Hi Jerry, The example document was never finished (not even really started :-(). So I am afraid that nothing is available and the Audio working group is not active at this time... Kindest Regards, Geert Knapen President/Owner Design & Advice, L.L.C. 1725 Martin Avenue, San Jose CA 95128 e-mail: geert@xxxxxxxxxxxxxxxxxxx | Tel: +1-408-297-3731 | Cell: +1-408-507-7852 | Google Voice: +1-408-805-4320 On Mar 23, 2014, at 12:26 PM, Jerry Evans <jerry@xxxxxxxxxxx> wrote: > Hello Geert > > I wonder if you might be able to help with a more general AC2 issue. In the > list of ‘Key Differences’, the Release 2.0 ‘device class definition for Audio > Devices’ document states that ‘split off the examples in a separate > document’. Did any such document ever get published? Is there a draft > available perhaps? Given the (sad) paucity of AC2 compliant devices such a > document would be extremely helpful for implementors … > > Many thanks > > Jerry > > From: wdmaudiodev-bounce@xxxxxxxxxxxxx > [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Geert Knapen > Sent: 14 February 2014 23:09 > To: wdmaudiodev@xxxxxxxxxxxxx > Subject: [wdmaudiodev] Re: USB Audio Class 2.0 > > May I suggest to have a look at Section 2.1 in the Audio 2.0 spec: > 2.1 Overview of Key Differences between ADC v1.0 and v2.0 > > The following list is not an exhaustive list of all changes that have been > introduced. For complete information, refer to the full specification. Pay > special attention to Sections 1 through 6! > > · Complete support for high speed operation - no longer are audio > class devices limited to full speed operation. > > · The notion of physical and logical Audio channel clusters. > > · The number of predefined spatial locations has increased. In > addition, a virtual spatial location > > called Raw Data was introduced. > > · Use of the interface association descriptor - The standard > Interface Association mechanism is used > > to describe an Audio Interface Collection. The former class specific > mechanism was deprecated. > > · Descriptor updates: fixed offsets associated with many descriptors > and enlarged three byte fields > > into four bytes. > > · Extensive support for interrupts to inform the host about dynamic > changes that occur on the > > different addressable Entities (Clock Entities, Terminals, Units, interfaces > and endpoints) inside > > the audio function. > > · More clarification text on the audio function. > > · Audio Control Changes. > > o – Control attribute changes. > > o – Mixer Unit control request (set/get pairs changed). > > o – Many updates in the control descriptions. > > · Added support for clock domains, clock description and clock > control. > > · Added additional Audio Controls inside a Feature Unit (Input, Gain, > Input Gain Pad ...) > > · Added bit pairs in descriptors to indicate presence and > programmability of every Control > > · Prohibited the use of Alternate Setting switching to change > sampling frequencies. Instead, Clock > > Entities are introduced that can be manipulated (through the AudioControl > interface) to select > > operating sampling frequencies. > > · Split off the examples in a separate document. > > · Allowed binding between physical buttons on the audio function and > the corresponding Audio > > Control. Prescribed how this is done. > > · Added an Effect Unit to group algorithms that work on logical > channels separately but require > > multiple parameters to manipulate the effect (as opposed to basic (single > parameter) manipulation, > > performed in a Feature Unit). > > · Introduced Parametric Equalizer Section Effect Unit. > > · Rearranged Reverb, Modulation Delay and Dynamic Compressor PUs > under the new Effect Unit. > > · Added the concept of audio function Category. The Category > indicates the primary use of the > > audio function as envisioned by the manufacturer. > > · Added the Sampling Rate Converter Unit. > > · Added a means to express Latency of individual building blocks > within the audio function. > > · Added Encoder support. > > Of course, these are all technical differences and do not necessarily > directly translate in specific reasons to invest in Audio 2.0 :-) > > Kindest Regards, > > Geert Knapen > USB Audio DWG Chair > > <~WRD000.jpg><~WRD000.jpg>Geert Knapen > > > Design & Advice, L.L.C. > 1725 Martin Avenue, San Jose CA 95128 > e-mail: geert@xxxxxxxxxxxxxxxxxxx | Tel: +1-408-297-3731 | Cell: > +1-408-507-7852 | Google Voice: +1-408-805-4320 > > On Feb 14, 2014, at 2:45 PM, Matthew van Eerde > <Matthew.van.Eerde@xxxxxxxxxxxxx> wrote: > > > Specific reasons to invest in USB Audio 2.0: > > * Higher bit rate enables more formats > * Dynamic jack presence detection > * Anything else? > > -----Original Message----- > From: wdmaudiodev-bounce@xxxxxxxxxxxxx > [mailto:wdmaudiodev-bounce@xxxxxxxxxxxxx] On Behalf Of Børge Strand-Bergesen > Sent: Friday, February 14, 2014 2:38 PM > To: wdmaudiodev@xxxxxxxxxxxxx > Subject: [wdmaudiodev] Re: USB Audio Class 2.0 > > Thank you Phil. > > The market demands Hi-Res, science of not. > > Microsoft will sell more OS licenses with UAC2 support. Apple will > sell less Macs with Windows UAC2 support. Enough to justify the > investment? I think yes. Enough to get a measurable peak on the first > quarterly report? Probably not. > > > Børge > > P.S. I'm sorry for going OT with the mention of megapixels and MHz. > I'm just trying to see the world of electroncis through the eyes of > the people browsing the shelves at Best Buy. Having a number to > compare will tip their scale. Lots of users will ignore the not easily > quantifiable quality of the optics if the other camera has more > pixels. Currently, UAC2 DACs don't play out of the box, and they sell > to customers who care about the quality of the optics. Make them play > out of the box and they will sell to the much larger crowd which > doesn't. > > P.P.S Don't forget the placebo effect. This DAC has more X than that > other one, so it _must_ sound better. No UAC2, no cake! > > > On Fri, Feb 14, 2014 at 7:42 PM, Philip Gruebele <pgruebele@xxxxxxx> wrote: > > Three points worth making: > > 1. Whether or not it is technically necessary to support higher sample rates > is not relevant. What is relevant is whether the market demands it, and it > undeniably does. Otherwise why would so many companies - hardware > manufacturers and download services - invest so many resources to make it > happen? > > 2. Using Nyquist and human hearing to make a case for not supporting higher > sample rates is looking at the issue too narrowly. The reason higher sample > rates can be better are complex and include things like simplifying DAC > design and out-of-band filtering. Also some protocols like DSD64 over DoP > require 176.4Khz and DSD128 requires double that just to get the data > across. UA2.0 also supports certain use cases which are not possible with > UA1.0. The minimum sample rate that should be supported is at least 384Khz > and UA2.0 has handled all these cases for many years. > > 3. The lack of USB Audio 2.0 support causes a headache for consumers because > they have to deal with low quality, poorly test, third party drivers. These > drivers are not going away because of point (1). There are a LOT of high-end > audio enthusiasts who voted against Windows by using Apple products because > they provide a better end-user experience. > > -phil > > Tim Roberts wrote: > > > Børge Strand-Bergesen wrote: > > > I'm sorry Tim, but this is like saying Canon & Co. should have stopped > adding megapixels once their cameras got 4 or so of them. > > No, this is not a valid comparison. Our eyes can tell the difference > > between 300dpi and 600dpi, and a 4MP camera can only do about 200dpi > when printed at 8.5x11. Those extra pixels ARE being put to use. > > The same is simply not true of audio. You don't "zoom in" on an audio > track. The concept doesn't make sense. The best human ears are > physically unable to sense frequencies above about 20kHz. Per Nyquist, > anything above twice that frequency serves no purpose at all. They > CANNOT, physically, alter what we sense in the sound. > > It reminds me of the "Dominator DMX 10" scene from Ruthless People: > http://www.youtube.com/watch?v=mNzr6lfiHJE > (Caution: language) > > > > kHz is a simple number. Comparing the kHz of your audio system will be > done in the consumer crowds just like they compared the MHz of their > CPUs and the megapixels of their cameras. The more you have of that > simple metric, the better they will feel. > > That's voodoo, not engineering. Those MHz and megapixels are being > > used. Those extra kHz are utterly pointless. Unlike the other two, we > have reached a physical limit. > > > ****************** > > WDMAUDIODEV addresses: > Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx > Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe > Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe > Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx > > URL to WDMAUDIODEV page: > http://www.wdmaudiodev.com/ > > ****************** > > WDMAUDIODEV addresses: > Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx > Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe > Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe > Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx > > URL to WDMAUDIODEV page: > http://www.wdmaudiodev.com/ > > ****************** > > WDMAUDIODEV addresses: > Post message: mailto:wdmaudiodev@xxxxxxxxxxxxx > Subscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=subscribe > Unsubscribe: mailto:wdmaudiodev-request@xxxxxxxxxxxxx?subject=unsubscribe > Moderator: mailto:wdmaudiodev-moderators@xxxxxxxxxxxxx > > URL to WDMAUDIODEV page: > http://www.wdmaudiodev.com/ >