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Thibault Le Meurcac19c32007-07-13 11:50:23 +02001 Guide to using M-Audio Audiophile USB with ALSA and Jack v1.5
Thibault LE MEURe3113342006-03-14 11:44:53 +01002 ========================================================
3
4 Thibault Le Meur <Thibault.LeMeur@supelec.fr>
5
6This document is a guide to using the M-Audio Audiophile USB (tm) device with
7ALSA and JACK.
8
Thibault Le Meurf8c78b82007-07-12 11:26:35 +02009History
10=======
11* v1.4 - Thibault Le Meur (2007-07-11)
12 - Added Low Endianness nature of 16bits-modes
13 found by Hakan Lennestal <Hakan.Lennestal@brfsodrahamn.se>
14 - Modifying document structure
Thibault Le Meurcac19c32007-07-13 11:50:23 +020015* v1.5 - Thibault Le Meur (2007-07-12)
16 - Added AC3/DTS passthru info
Thibault Le Meurf8c78b82007-07-12 11:26:35 +020017
18
Thibault LE MEURe3113342006-03-14 11:44:53 +0100191 - Audiophile USB Specs and correct usage
20==========================================
Thibault Le Meurf8c78b82007-07-12 11:26:35 +020021
Thibault LE MEURe3113342006-03-14 11:44:53 +010022This part is a reminder of important facts about the functions and limitations
23of the device.
24
25The device has 4 audio interfaces, and 2 MIDI ports:
26 * Analog Stereo Input (Ai)
Thibault LE MEUR19739fe2006-03-21 11:06:40 +010027 - This port supports 2 pairs of line-level audio inputs (1/4" TS and RCA)
28 - When the 1/4" TS (jack) connectors are connected, the RCA connectors
29 are disabled
Thibault LE MEURe3113342006-03-14 11:44:53 +010030 * Analog Stereo Output (Ao)
31 * Digital Stereo Input (Di)
32 * Digital Stereo Output (Do)
33 * Midi In (Mi)
34 * Midi Out (Mo)
35
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +020036The internal DAC/ADC has the following characteristics:
Thibault LE MEURe3113342006-03-14 11:44:53 +010037* sample depth of 16 or 24 bits
38* sample rate from 8kHz to 96kHz
Thibault Le Meurf8c78b82007-07-12 11:26:35 +020039* Two interfaces can't use different sample depths at the same time.
40Moreover, the Audiophile USB documentation gives the following Warning:
41"Please exit any audio application running before switching between bit depths"
Thibault LE MEURe3113342006-03-14 11:44:53 +010042
43Due to the USB 1.1 bandwidth limitation, a limited number of interfaces can be
44activated at the same time depending on the audio mode selected:
Thibault Le Meurf8c78b82007-07-12 11:26:35 +020045 * 16-bit/48kHz ==> 4 channels in + 4 channels out
Thibault LE MEURe3113342006-03-14 11:44:53 +010046 - Ai+Ao+Di+Do
Thibault Le Meurf8c78b82007-07-12 11:26:35 +020047 * 24-bit/48kHz ==> 4 channels in + 2 channels out,
48 or 2 channels in + 4 channels out
Thibault LE MEURe3113342006-03-14 11:44:53 +010049 - Ai+Ao+Do or Ai+Di+Ao or Ai+Di+Do or Di+Ao+Do
Thibault Le Meurf8c78b82007-07-12 11:26:35 +020050 * 24-bit/96kHz ==> 2 channels in _or_ 2 channels out (half duplex only)
Thibault LE MEURe3113342006-03-14 11:44:53 +010051 - Ai or Ao or Di or Do
52
53Important facts about the Digital interface:
54--------------------------------------------
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +020055 * The Do port additionally supports surround-encoded AC-3 and DTS passthrough,
56though I haven't tested it under Linux
Thibault LE MEURe3113342006-03-14 11:44:53 +010057 - Note that in this setup only the Do interface can be enabled
58 * Apart from recording an audio digital stream, enabling the Di port is a way
Thibault LE MEUR19739fe2006-03-21 11:06:40 +010059to synchronize the device to an external sample clock
Thibault LE MEURe3113342006-03-14 11:44:53 +010060 - As a consequence, the Di port must be enable only if an active Digital
61source is connected
62 - Enabling Di when no digital source is connected can result in a
63synchronization error (for instance sound played at an odd sample rate)
64
65
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200662 - Audiophile USB MIDI support in ALSA
67=======================================
Thibault LE MEURe3113342006-03-14 11:44:53 +010068
Thibault Le Meurf8c78b82007-07-12 11:26:35 +020069The Audiophile USB MIDI ports will be automatically supported once the
Thibault LE MEURe3113342006-03-14 11:44:53 +010070following modules have been loaded:
71 * snd-usb-audio
Thibault LE MEURe3113342006-03-14 11:44:53 +010072 * snd-seq-midi
73
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +020074No additional setting is required.
Thibault LE MEURe3113342006-03-14 11:44:53 +010075
Thibault Le Meurf8c78b82007-07-12 11:26:35 +020076
773 - Audiophile USB Audio support in ALSA
78========================================
Thibault LE MEURe3113342006-03-14 11:44:53 +010079
80Audio functions of the Audiophile USB device are handled by the snd-usb-audio
81module. This module can work in a default mode (without any device-specific
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +020082parameter), or in an "advanced" mode with the device-specific parameter called
Thibault LE MEURe3113342006-03-14 11:44:53 +010083"device_setup".
84
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200853.1 - Default Alsa driver mode
86------------------------------
Thibault LE MEURe3113342006-03-14 11:44:53 +010087
Thibault Le Meurf8c78b82007-07-12 11:26:35 +020088The default behavior of the snd-usb-audio driver is to list the device
89capabilities at startup and activate the required mode when required
90by the applications: for instance if the user is recording in a
9124bit-depth-mode and immediately after wants to switch to a 16bit-depth mode,
92the snd-usb-audio module will reconfigure the device on the fly.
Thibault LE MEURe3113342006-03-14 11:44:53 +010093
Thibault Le Meurf8c78b82007-07-12 11:26:35 +020094This approach has the advantage to let the driver automatically switch from sample
95rates/depths automatically according to the user's needs. However, those who
96are using the device under windows know that this is not how the device is meant to
97work: under windows applications must be closed before using the m-audio control
98panel to switch the device working mode. Thus as we'll see in next section, this
99Default Alsa driver mode can lead to device misconfigurations.
100
101Let's get back to the Default Alsa driver mode for now. In this case the
102Audiophile interfaces are mapped to alsa pcm devices in the following
103way (I suppose the device's index is 1):
Thibault LE MEURe3113342006-03-14 11:44:53 +0100104 * hw:1,0 is Ao in playback and Di in capture
105 * hw:1,1 is Do in playback and Ai in capture
106 * hw:1,2 is Do in AC3/DTS passthrough mode
107
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200108In this mode, the device uses Big Endian byte-encoding so that
109supported audio format are S16_BE for 16-bit depth modes and S24_3BE for
Thibault Le Meurcac19c32007-07-13 11:50:23 +020011024-bits depth mode.
111
112One exception is the hw:1,2 port which was reported to be Little Endian
113compliant (supposedly supporting S16_LE) but processes in fact only S16_BE streams.
114This has been fixed in kernel 2.6.23 and above and now the hw:1,2 interface
115is reported to be big endian in this default driver mode.
Thibault LE MEURe3113342006-03-14 11:44:53 +0100116
117Examples:
118 * playing a S24_3BE encoded raw file to the Ao port
119 % aplay -D hw:1,0 -c2 -t raw -r48000 -fS24_3BE test.raw
120 * recording a S24_3BE encoded raw file from the Ai port
121 % arecord -D hw:1,1 -c2 -t raw -r48000 -fS24_3BE test.raw
122 * playing a S16_BE encoded raw file to the Do port
123 % aplay -D hw:1,1 -c2 -t raw -r48000 -fS16_BE test.raw
Thibault Le Meurcac19c32007-07-13 11:50:23 +0200124 * playing an ac3 sample file to the Do port
125 % aplay -D hw:1,2 --channels=6 ac3_S16_BE_encoded_file.raw
Thibault LE MEURe3113342006-03-14 11:44:53 +0100126
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200127If you're happy with the default Alsa driver mode and don't experience any
Thibault LE MEURe3113342006-03-14 11:44:53 +0100128issue with this mode, then you can skip the following chapter.
129
Thibault Le Meurf8c78b82007-07-12 11:26:35 +02001303.2 - Advanced module setup
131---------------------------
Thibault LE MEURe3113342006-03-14 11:44:53 +0100132
133Due to the hardware constraints described above, the device initialization made
134by the Alsa driver in default mode may result in a corrupted state of the
135device. For instance, a particularly annoying issue is that the sound captured
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200136from the Ai interface sounds distorted (as if boosted with an excessive high
137volume gain).
Thibault LE MEURe3113342006-03-14 11:44:53 +0100138
139For people having this problem, the snd-usb-audio module has a new module
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200140parameter called "device_setup" (this parameter was introduced in kernel
141release 2.6.17)
Thibault LE MEURe3113342006-03-14 11:44:53 +0100142
Thibault Le Meurf8c78b82007-07-12 11:26:35 +02001433.2.1 - Initializing the working mode of the Audiophile USB
Thibault LE MEURe3113342006-03-14 11:44:53 +0100144
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200145As far as the Audiophile USB device is concerned, this value let the user
Thibault LE MEURe3113342006-03-14 11:44:53 +0100146specify:
147 * the sample depth
148 * the sample rate
149 * whether the Di port is used or not
150
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200151When initialized with "device_setup=0x00", the snd-usb-audio module has
152the same behaviour as when the parameter is omitted (see paragraph "Default
153Alsa driver mode" above)
154
155Others modes are described in the following subsections.
156
1573.2.1.1 - 16-bit modes
158
159The two supported modes are:
160
Thibault LE MEURe3113342006-03-14 11:44:53 +0100161 * device_setup=0x01
162 - 16bits 48kHz mode with Di disabled
163 - Ai,Ao,Do can be used at the same time
164 - hw:1,0 is not available in capture mode
165 - hw:1,2 is not available
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200166
Thibault LE MEURe3113342006-03-14 11:44:53 +0100167 * device_setup=0x11
168 - 16bits 48kHz mode with Di enabled
169 - Ai,Ao,Di,Do can be used at the same time
170 - hw:1,0 is available in capture mode
171 - hw:1,2 is not available
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200172
173In this modes the device operates only at 16bits-modes. Before kernel 2.6.23,
174the devices where reported to be Big-Endian when in fact they were Little-Endian
175so that playing a file was a matter of using:
176 % aplay -D hw:1,1 -c2 -t raw -r48000 -fS16_BE test_S16_LE.raw
177where "test_S16_LE.raw" was in fact a little-endian sample file.
178
179Thanks to Hakan Lennestal (who discovered the Little-Endiannes of the device in
180these modes) a fix has been committed (expected in kernel 2.6.23) and
181Alsa now reports Little-Endian interfaces. Thus playing a file now is as simple as
182using:
183 % aplay -D hw:1,1 -c2 -t raw -r48000 -fS16_LE test_S16_LE.raw
184
1853.2.1.2 - 24-bit modes
186
187The three supported modes are:
188
Thibault LE MEURe3113342006-03-14 11:44:53 +0100189 * device_setup=0x09
190 - 24bits 48kHz mode with Di disabled
191 - Ai,Ao,Do can be used at the same time
192 - hw:1,0 is not available in capture mode
193 - hw:1,2 is not available
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200194
Thibault LE MEURe3113342006-03-14 11:44:53 +0100195 * device_setup=0x19
196 - 24bits 48kHz mode with Di enabled
197 - 3 ports from {Ai,Ao,Di,Do} can be used at the same time
198 - hw:1,0 is available in capture mode and an active digital source must be
199 connected to Di
200 - hw:1,2 is not available
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200201
Thibault LE MEURe3113342006-03-14 11:44:53 +0100202 * device_setup=0x0D or 0x10
203 - 24bits 96kHz mode
204 - Di is enabled by default for this mode but does not need to be connected
205 to an active source
206 - Only 1 port from {Ai,Ao,Di,Do} can be used at the same time
207 - hw:1,0 is available in captured mode
208 - hw:1,2 is not available
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200209
210In these modes the device is only Big-Endian compliant (see "Default Alsa driver
211mode" above for an aplay command example)
212
2133.2.1.3 - AC3 w/ DTS passthru mode
214
Thibault Le Meurcac19c32007-07-13 11:50:23 +0200215Thanks to Hakan Lennestal, I now have a report saying that this mode works.
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200216
Thibault LE MEURe3113342006-03-14 11:44:53 +0100217 * device_setup=0x03
218 - 16bits 48kHz mode with only the Do port enabled
Thibault Le Meurcac19c32007-07-13 11:50:23 +0200219 - AC3 with DTS passthru
Thibault LE MEURe3113342006-03-14 11:44:53 +0100220 - Caution with this setup the Do port is mapped to the pcm device hw:1,0
221
Thibault Le Meurcac19c32007-07-13 11:50:23 +0200222The command line used to playback the AC3/DTS encoded .wav-files in this mode:
223 % aplay -D hw:1,0 --channels=6 ac3_S16_LE_encoded_file.raw
224
Thibault Le Meurf8c78b82007-07-12 11:26:35 +02002253.2.2 - How to use the device_setup parameter
226----------------------------------------------
Thibault LE MEURe3113342006-03-14 11:44:53 +0100227
228The parameter can be given:
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200229
Thibault LE MEURe3113342006-03-14 11:44:53 +0100230 * By manually probing the device (as root):
231 # modprobe -r snd-usb-audio
232 # modprobe snd-usb-audio index=1 device_setup=0x09
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200233
Thibault LE MEURe3113342006-03-14 11:44:53 +0100234 * Or while configuring the modules options in your modules configuration file
235 - For Fedora distributions, edit the /etc/modprobe.conf file:
236 alias snd-card-1 snd-usb-audio
237 options snd-usb-audio index=1 device_setup=0x09
238
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200239CAUTION when initializaing the device
240-------------------------------------
241
242 * Correct initialization on the device requires that device_setup is given to
243 the module BEFORE the device is turned on. So, if you use the "manual probing"
244 method described above, take care to power-on the device AFTER this initialization.
245
246 * Failing to respect this will lead in a misconfiguration of the device. In this case
247 turn off the device, unproble the snd-usb-audio module, then probe it again with
248 correct device_setup parameter and then (and only then) turn on the device again.
249
250 * If you've correctly initialized the device in a valid mode and then want to switch
251 to another mode (possibly with another sample-depth), please use also the following
252 procedure:
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200253 - first turn off the device
254 - de-register the snd-usb-audio module (modprobe -r)
255 - change the device_setup parameter by changing the device_setup
256 option in /etc/modprobe.conf
Thibault LE MEURe3113342006-03-14 11:44:53 +0100257 - turn on the device
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200258 * A workaround for this last issue has been applied to kernel 2.6.23, but it may not
259 be enough to ensure the 'stability' of the device initialization.
Thibault LE MEURe3113342006-03-14 11:44:53 +0100260
Thibault Le Meurf8c78b82007-07-12 11:26:35 +02002613.2.3 - Technical details for hackers
262-------------------------------------
263This section is for hackers, wanting to understand details about the device
264internals and how Alsa supports it.
265
2663.2.3.1 - Audiophile USB's device_setup structure
Thibault LE MEURe3113342006-03-14 11:44:53 +0100267
268If you want to understand the device_setup magic numbers for the Audiophile
269USB, you need some very basic understanding of binary computation. However,
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200270this is not required to use the parameter and you may skip this section.
Thibault LE MEURe3113342006-03-14 11:44:53 +0100271
272The device_setup is one byte long and its structure is the following:
273
274 +---+---+---+---+---+---+---+---+
275 | b7| b6| b5| b4| b3| b2| b1| b0|
276 +---+---+---+---+---+---+---+---+
277 | 0 | 0 | 0 | Di|24B|96K|DTS|SET|
278 +---+---+---+---+---+---+---+---+
279
280Where:
281 * b0 is the "SET" bit
282 - it MUST be set if device_setup is initialized
283 * b1 is the "DTS" bit
284 - it is set only for Digital output with DTS/AC3
285 - this setup is not tested
286 * b2 is the Rate selection flag
287 - When set to "1" the rate range is 48.1-96kHz
288 - Otherwise the sample rate range is 8-48kHz
289 * b3 is the bit depth selection flag
290 - When set to "1" samples are 24bits long
291 - Otherwise they are 16bits long
292 - Note that b2 implies b3 as the 96kHz mode is only supported for 24 bits
293 samples
294 * b4 is the Digital input flag
295 - When set to "1" the device assumes that an active digital source is
296 connected
297 - You shouldn't enable Di if no source is seen on the port (this leads to
298 synchronization issues)
299 - b4 is implied by b2 (since only one port is enabled at a time no synch
300 error can occur)
301 * b5 to b7 are reserved for future uses, and must be set to "0"
302 - might become Ao, Do, Ai, for b7, b6, b4 respectively
303
304Caution:
305 * there is no check on the value you will give to device_setup
306 - for instance choosing 0x05 (16bits 96kHz) will fail back to 0x09 since
307 b2 implies b3. But _there_will_be_no_warning_ in /var/log/messages
308 * Hardware constraints due to the USB bus limitation aren't checked
309 - choosing b2 will prepare all interfaces for 24bits/96kHz but you'll
310 only be able to use one at the same time
311
Thibault Le Meurf8c78b82007-07-12 11:26:35 +02003123.2.3.2 - USB implementation details for this device
Thibault LE MEURe3113342006-03-14 11:44:53 +0100313
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200314You may safely skip this section if you're not interested in driver
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200315hacking.
Thibault LE MEURe3113342006-03-14 11:44:53 +0100316
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200317This section describes some internal aspects of the device and summarizes the
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200318data I got by usb-snooping the windows and Linux drivers.
Thibault LE MEURe3113342006-03-14 11:44:53 +0100319
Thibault LE MEUR19739fe2006-03-21 11:06:40 +0100320The M-Audio Audiophile USB has 7 USB Interfaces:
Thibault LE MEURe3113342006-03-14 11:44:53 +0100321a "USB interface":
Thibault LE MEUR19739fe2006-03-21 11:06:40 +0100322 * USB Interface nb.0
323 * USB Interface nb.1
Thibault LE MEURe3113342006-03-14 11:44:53 +0100324 - Audio Control function
Thibault LE MEUR19739fe2006-03-21 11:06:40 +0100325 * USB Interface nb.2
Thibault LE MEURe3113342006-03-14 11:44:53 +0100326 - Analog Output
Thibault LE MEUR19739fe2006-03-21 11:06:40 +0100327 * USB Interface nb.3
Thibault LE MEURe3113342006-03-14 11:44:53 +0100328 - Digital Output
Thibault LE MEUR19739fe2006-03-21 11:06:40 +0100329 * USB Interface nb.4
Thibault LE MEURe3113342006-03-14 11:44:53 +0100330 - Analog Input
Thibault LE MEUR19739fe2006-03-21 11:06:40 +0100331 * USB Interface nb.5
Thibault LE MEURe3113342006-03-14 11:44:53 +0100332 - Digital Input
Thibault LE MEUR19739fe2006-03-21 11:06:40 +0100333 * USB Interface nb.6
Thibault LE MEURe3113342006-03-14 11:44:53 +0100334 - MIDI interface compliant with the MIDIMAN quirk
335
336Each interface has 5 altsettings (AltSet 1,2,3,4,5) except:
337 * Interface 3 (Digital Out) has an extra Alset nb.6
338 * Interface 5 (Digital In) does not have Alset nb.3 and 5
339
340Here is a short description of the AltSettings capabilities:
341 * AltSettings 1 corresponds to
342 - 24-bit depth, 48.1-96kHz sample mode
343 - Adaptive playback (Ao and Do), Synch capture (Ai), or Asynch capture (Di)
344 * AltSettings 2 corresponds to
345 - 24-bit depth, 8-48kHz sample mode
346 - Asynch capture and playback (Ao,Ai,Do,Di)
347 * AltSettings 3 corresponds to
348 - 24-bit depth, 8-48kHz sample mode
349 - Synch capture (Ai) and Adaptive playback (Ao,Do)
350 * AltSettings 4 corresponds to
351 - 16-bit depth, 8-48kHz sample mode
352 - Asynch capture and playback (Ao,Ai,Do,Di)
353 * AltSettings 5 corresponds to
354 - 16-bit depth, 8-48kHz sample mode
355 - Synch capture (Ai) and Adaptive playback (Ao,Do)
356 * AltSettings 6 corresponds to
357 - 16-bit depth, 8-48kHz sample mode
358 - Synch playback (Do), audio format type III IEC1937_AC-3
359
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200360In order to ensure a correct initialization of the device, the driver
Thibault LE MEURe3113342006-03-14 11:44:53 +0100361_must_know_ how the device will be used:
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200362 * if DTS is chosen, only Interface 2 with AltSet nb.6 must be
Thibault LE MEURe3113342006-03-14 11:44:53 +0100363 registered
364 * if 96KHz only AltSets nb.1 of each interface must be selected
365 * if samples are using 24bits/48KHz then AltSet 2 must me used if
366 Digital input is connected, and only AltSet nb.3 if Digital input
367 is not connected
368 * if samples are using 16bits/48KHz then AltSet 4 must me used if
369 Digital input is connected, and only AltSet nb.5 if Digital input
370 is not connected
371
372When device_setup is given as a parameter to the snd-usb-audio module, the
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200373parse_audio_endpoints function uses a quirk called
Thibault LE MEURe3113342006-03-14 11:44:53 +0100374"audiophile_skip_setting_quirk" in order to prevent AltSettings not
375corresponding to device_setup from being registered in the driver.
376
Thibault Le Meurf8c78b82007-07-12 11:26:35 +02003774 - Audiophile USB and Jack support
Thibault LE MEURe3113342006-03-14 11:44:53 +0100378===================================
379
380This section deals with support of the Audiophile USB device in Jack.
Thibault LE MEURe3113342006-03-14 11:44:53 +0100381
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200382There are 2 main potential issues when using Jackd with the device:
383* support for Big-Endian devices in 24-bit modes
384* support for 4-in / 4-out channels
Thibault LE MEURe3113342006-03-14 11:44:53 +0100385
Thibault Le Meurf8c78b82007-07-12 11:26:35 +02003864.1 - Direct support in Jackd
387-----------------------------
388
389Jack supports big endian devices only in recent versions (thanks to
390Andreas Steinmetz for his first big-endian patch). I can't remember
391extacly when this support was released into jackd, let's just say that
392with jackd version 0.103.0 it's almost ok (just a small bug is affecting
39316bits Big-Endian devices, but since you've read carefully the above
394paragraphs, you're now using kernel >= 2.6.23 and your 16bits devices
395are now Little Endians ;-) ).
396
397You can run jackd with the following command for playback with Ao and
398record with Ai:
399 % jackd -R -dalsa -Phw:1,0 -r48000 -p128 -n2 -D -Chw:1,1
400
4014.2 - Using Alsa plughw
402-----------------------
403If you don't have a recent Jackd installed, you can downgrade to using
404the Alsa "plug" converter.
Thibault LE MEURe3113342006-03-14 11:44:53 +0100405
406For instance here is one way to run Jack with 2 playback channels on Ao and 2
407capture channels from Ai:
408 % jackd -R -dalsa -dplughw:1 -r48000 -p256 -n2 -D -Cplughw:1,1
409
Thibault LE MEURe3113342006-03-14 11:44:53 +0100410However you may see the following warning message:
411"You appear to be using the ALSA software "plug" layer, probably a result of
412using the "default" ALSA device. This is less efficient than it could be.
413Consider using a hardware device instead rather than using the plug layer."
414
Thibault Le Meurf8c78b82007-07-12 11:26:35 +02004154.3 - Getting 2 input and/or output interfaces in Jack
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200416------------------------------------------------------
417
418As you can see, starting the Jack server this way will only enable 1 stereo
419input (Di or Ai) and 1 stereo output (Ao or Do).
420
421This is due to the following restrictions:
422* Jack can only open one capture device and one playback device at a time
423* The Audiophile USB is seen as 2 (or three) Alsa devices: hw:1,0, hw:1,1
424 (and optionally hw:1,2)
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200425
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200426If you want to get Ai+Di and/or Ao+Do support with Jack, you would need to
427combine the Alsa devices into one logical "complex" device.
428
429If you want to give it a try, I recommend reading the information from
430this page: http://www.sound-man.co.uk/linuxaudio/ice1712multi.html
431It is related to another device (ice1712) but can be adapted to suit
432the Audiophile USB.
433
434Enabling multiple Audiophile USB interfaces for Jackd will certainly require:
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200435* Making sure your Jackd version has the MMAP_COMPLEX patch (see the ice1712 page)
436* (maybe) patching the alsa-lib/src/pcm/pcm_multi.c file (see the ice1712 page)
Charis Kouzinopoulos5732e7a2006-04-18 15:42:29 +0200437* define a multi device (combination of hw:1,0 and hw:1,1) in your .asoundrc
438 file
439* start jackd with this device
440
Thibault Le Meurf8c78b82007-07-12 11:26:35 +0200441I had no success in testing this for now, if you have any success with this kind
442of setup, please drop me an email.