[linux-audio-user] Re: Feasibility of Crestron like Linux Based Whole

Andrew Burgess aab at cichlid.com
Sun Jan 2 17:14:59 EST 2005


I have a system similar to what you are thinking about

>Each destination is equiped with speakers only.  At this time, the 
>speakers are wired to a central location

Yep. I use 2 USB soundcards to give me 6 stereo channels. I can play
6 different mp3 sources to 6 rooms.

..
>I want to replace the SonAMP 260 with a multizone amplifier or a bank of 
>amplifiers. 

I use a hodgepodge of amps currently. Volume control in software
(as well as loudness and misc signal processing via LADSPA plugins)

>I want to be able to hook my sources up to a linux box.  I want
>the linux box to also be a source so I could load CD's and have it act 
>as a jukebox.  Then all outputs will go from the linux box into the  bank of
>amplifiers which in turn is hooked to the speaker pairs throughout the 
>house.

Yep. In addition to mp3s I support a D-link USB FM radio, internet
streaming audio (eg NPR programs via realaudio protocols) and synthesized
voice prompting.

>I want to control zone / source  and volume through a web browser 
>application.  That way, technically I could control everything from one 
>console

I use dumb X10 controllers ($10) and let the PC interpret the button pushes

>- not very practicle though.  But then I'd like to distribute - at 
>geographically convenient locations throughout the house - small, wall 
>mounted touch screen
>browser "appliances" (for lack of a better description) - which would be 
>used to run the web app and control the system anywhere I choose to 
>place one.

Voice prompts and speech recognition are the future :-) and oddly enough
the cheapest solution hardware-wise.

Today I'm running 2.6.7-1.437.1.ll.rhfc2.ccrmasmp, Ingo's newer stuff
doesn't work for me (either because of usb or my 3ware scsi card). My
performance is OK, I get the occasional xrun, but basically I'm pretty
happy running 6 stereo audio outputs and 4 mono audio inputs 24/7

The worst thing, CPU-wise, is sample rate conversion. My usb soundcards
(EMI 2|6 and Maya EX7 USB) run at 48KHz and my mp3s are usually 44.1Khz. Its
about 5% cpu per stereo channel (P4 HT 2.8 Ghz) to convert this. Mp3 decode is
nothing by comparison. Sample rate conv is courtesy libsamplerate and mp3
decode is via MAD.

Its all controlled by a custom home automation app and portaudio. I used to
run through jack but when I went to 2 soundcards jack wasn't supporting more
than one (it does now). I use jack with its dummy driver now for eye-candy
apps: meterbridge etc

Well, a bit OT. Hope this was of interest to some of you.




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