Thank you very much for sharing! Nice...
On Sun, Aug 18, 2013 at 4:00 PM, Muffinman <[email protected]> wrote: > Hello all, > > A while back I asked on this mailinglist on how to control volume of an > amplifier via MPD through a serial connection (rs232/ttl). Time passed > without an answer, so I did some digging and learned C. While building > the app I figured I might as well expand compatibility. While it doesn't > support every amplifier (with a serial connection), it does have quit > broad support and can in some cases be extended if needed. In addition, > in combination with MPoD/MPaD it also give control over input, power, > and whatever options the amp has. Last, but not least: it syncs data > both ways, from computer to amp and back. > > In short, the inner workings: applications such as MPD, but also > shairport (dev 1.0), have the option to use a different soundcard for > mixer controls. Therefore, we set MPD etc. to send volume control data > to a dummy soundcard. Alsa notifies the application volume has changed > which in turn sends the appropriate serial command to the amplifier. For > other options icm with MPoD/MPaD a small PHP script notifies the > application what to do. The amplifier in turn notifies the application > of any changes in volume, power, or input changes (if needed by explicit > request of the application). > > Broad support is somewhat frustrated by strange decisions of > manufacturers to have a bit of silly serial command structures: > completely different commands & structures for incoming and outgoing > commands (Parasound) or have a completely different volume range for > incoming (-93, 14) and outgoing volume commands (-150, -50, Classe). > Anyways, in such cases support is limited (for now at least). > > Initially I've created the app for Leema Acoustics, so that's 100% > supported. The following brands (fully or partially) supported: > Cambridge Audio, Classe, NAD, Parasound. Ayre should be supported, but I > don't have enough documentation on that to be sure. Cyrus can have > support if anyone cares. Other than Leema (and Classe to some extent) I > have not done any testing yet. But looking at the relevant documentation > and having hooked up my computer to Classe, NAD... it should work. Once > I have gotten myself the required cables I will hook them up and do some > real testing. Though anyone else willing to do some testing is very > welcome. > > Enough introductory talk: after reading the few notes below, all files > and instructions can be downloaded at the ftp address below. > - I don't take any responsibility for anything that may or may not happen. > - The app is still in beta and needs further testing. > - Be very careful when installing and testing regardless of its beta > state: unplug speakers when testing or disconnect any sources. If > something goes wrong, either faulty configuration or a bug, volume could > go to unwanted heights (though I've never experienced that result). > - The application allows volume limits to be configured, use it. You > don't need to go to 100% volume through MPD, more likely, you don't want > that. So, don't configure it. > - Be careful of security. Anyone with access to your computer can modify > its configuration. Well, use your imagination, the results in potentia. > - Any suggestions/improvements of the code are welcome: I'm a beginner > and probably violate every rule in the book. > > ftp://muffins.diskstation.me (guest login). > > If any question, please do ask. > > Kind regards, Maarten > > _______________________________________________ > Voyage-linux mailing list > [email protected] > http://list.voyage.hk/mailman/listinfo/voyage-linux >
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