1=================================================================
2Low latency, multichannel audio with JACK and the emu10k1/emu10k2
3=================================================================
4
5This document is a guide to using the emu10k1 based devices with JACK for low
6latency, multichannel recording functionality.  All of my recent work to allow
7Linux users to use the full capabilities of their hardware has been inspired
8by the kX Project.  Without their work I never would have discovered the true
9power of this hardware.
10
11	http://www.kxproject.com
12						- Lee Revell, 2005.03.30
13
14
15Until recently, emu10k1 users on Linux did not have access to the same low
16latency, multichannel features offered by the "kX ASIO" feature of their
17Windows driver.  As of ALSA 1.0.9 this is no more!
18
19For those unfamiliar with kX ASIO, this consists of 16 capture and 16 playback
20channels.  With a post 2.6.9 Linux kernel, latencies down to 64 (1.33 ms) or
21even 32 (0.66ms) frames should work well.
22
23The configuration is slightly more involved than on Windows, as you have to
24select the correct device for JACK to use.  Actually, for qjackctl users it's
25fairly self explanatory - select Duplex, then for capture and playback select
26the multichannel devices, set the in and out channels to 16, and the sample
27rate to 48000Hz.  The command line looks like this:
28::
29
30  /usr/local/bin/jackd -R -dalsa -r48000 -p64 -n2 -D -Chw:0,2 -Phw:0,3 -S
31
32This will give you 16 input ports and 16 output ports.
33
34The 16 output ports map onto the 16 FX buses (or the first 16 of 64, for the
35Audigy).  The mapping from FX bus to physical output is described in
36sb-live-mixer.rst (or audigy-mixer.rst).
37
38The 16 input ports are connected to the 16 physical inputs.  Contrary to
39popular belief, all emu10k1 cards are multichannel cards.  Which of these
40input channels have physical inputs connected to them depends on the card
41model.  Trial and error is highly recommended; the pinout diagrams
42for the card have been reverse engineered by some enterprising kX users and are
43available on the internet.  Meterbridge is helpful here, and the kX forums are
44packed with useful information.
45
46Each input port will either correspond to a digital (SPDIF) input, an analog
47input, or nothing.  The one exception is the SBLive! 5.1.  On these devices,
48the second and third input ports are wired to the center/LFE output.  You will
49still see 16 capture channels, but only 14 are available for recording inputs.
50
51This chart, borrowed from kxfxlib/da_asio51.cpp, describes the mapping of JACK
52ports to FXBUS2 (multitrack recording input) and EXTOUT (physical output)
53channels.
54
55JACK (& ASIO) mappings on 10k1 5.1 SBLive cards:
56
57==============  ========        ============
58JACK		Epilog		FXBUS2(nr)
59==============  ========        ============
60capture_1	asio14		FXBUS2(0xe)
61capture_2	asio15		FXBUS2(0xf)
62capture_3	asio0		FXBUS2(0x0)
63~capture_4	Center		EXTOUT(0x11)	// mapped to by Center
64~capture_5	LFE		EXTOUT(0x12)	// mapped to by LFE
65capture_6	asio3		FXBUS2(0x3)
66capture_7	asio4		FXBUS2(0x4)
67capture_8	asio5		FXBUS2(0x5)
68capture_9	asio6		FXBUS2(0x6)
69capture_10	asio7		FXBUS2(0x7)
70capture_11	asio8		FXBUS2(0x8)
71capture_12	asio9		FXBUS2(0x9)
72capture_13	asio10		FXBUS2(0xa)
73capture_14	asio11		FXBUS2(0xb)
74capture_15	asio12		FXBUS2(0xc)
75capture_16	asio13		FXBUS2(0xd)
76==============  ========        ============
77
78TODO: describe use of ld10k1/qlo10k1 in conjunction with JACK
79