You may be better off working with JACKd than straight-up ALSA. Also, you may want to look into PureData for your app. I've never used it though. Can anyone else chime in on this? - Alex Austin (651) 238-9273 "...and then I visited Wikipedia ...and the next 8 hours are a blur." On Fri, Dec 19, 2008 at 3:50 PM, Ronald <raalst@xxxxxxxxx> wrote: > Hi, all, > > I'm trying to develop a system which can determine the direction(s) > sound comes from. > In the end, it will be put in an R/c submarine, on a gumstix linux board > (see http://www.subcommittee.com for my hobby) > > But for now, I develop in air, with ubuntu. > all I want is to record using both the mic channel and the line in > (where another 2 mics are attached with a small preamp), > and I want to record while emitting a chirp, analyzing echo's. > the concept has been shown to work. see for instance > http://eddiem.com/projects/chirp/chirp.htm > > I am assuming that since all this goes via the same sound card, the same > crystal is used, and samples from mic and line in are > essentially synchronized (I only need it to be sync-ish for < 0,1 sec..) > > Now I have read a lot of ALSA tutorials and such like, but I'm lost. > a lot is about humans consuming nice harmonics, sharing and mixing, > which is not applicable to my case. > I have the nagging feeling OSS is a better fit for my case, but OSS is > apparently on a 60 day licence now. > > And, I am a newbie coder. no surprise there ;-) > > So, these are my questions : > > - Do I need to combine mic and line-in into one device using the > config file ? do I get a 3 channel device then ? does a plug-in add > latency ? > > - can I sync the transmission of a short chirp with the start of the > recording on these 3 channels ? is starting them close after each other > in the program OK, or is there possibly large latency caused *after* I > call the API ? the "real" sync'ing will be the (first) recording of the > chirp once it leaves the speaker, so it isn't critical, but I would like > to know because it might save a few bytes useless samples. > > - Does anybody out there have any links, code snippets or general > published info on how to apply ALSA to the robotics field ? > > Ps I have read the el-cheapo hack with multiple soundcards, and while a > very good idea, I cannot use it in the boat later on.. > > thanks for any input you might have. > > Regards, > Ronald van Aalst > > > _______________________________________________ > Alsa-devel mailing list > Alsa-devel@xxxxxxxxxxxxxxxx > http://mailman.alsa-project.org/mailman/listinfo/alsa-devel > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
