Well, don't follow those instructions exactly. I did and broke my alsa, but I think I've been here before, had to manually undo stuff. This was on a Raspberry Pi before but back in the summer I was doing nature recordings and using alsa (with aplay and arecord), sox, Audacity. The Pinebook Pro has about 6 hours battery life even running a USB soundcard so I was making 1/2 hour recordings by cron jobs. Using the wall wart it came with gave way too much noise. Hans Michlmayr was the guy's name, he was probably in the Outback. Web site seems to be gone now, he's possibly not still alive. Did a lot with radio interferometry. You can point an antenna at the sky and signals get strong and weak. But if you have 2 antennas as far apart as you can get them, then look at just what's in phase you can get much higher resolution. As the earth rotates it covers 360 degrees in one plane, summer-winter tilting gives a different plane. Signals from over the poles repeat more quickly than those overhead. You want as much gain as you can manage without feedback, from gain antennas and amplifier gain, like 100 db,. But you can sweep the sky and do plots, looking for quasars mostly. There are other radio sources like Jupiter. People use a pair of satellite TV dishes pointed up. I was into it 10 years ago, had a pair of antennas out. Never actually got anything, I was using an IC-7000 and when you turn the AGC off it mostly goes dead so I was imagining signals where there weren't any. On 12/26/20, Stuart Longland <stuartl@xxxxxxxxxxxxxxxxxx> wrote: > On 27/12/20 11:04 am, Alan Corey wrote: >> Uh-oh, I do have PulseAudio installed, didn't intend to. Using a >> Daniel Thompson Debian Bullseye on a Piinebook Pro. It's been up less >> than 4 days. Getting PulseAudio and alsa to coexist is a pain because >> Pulse wants to break alsa. I did it once following some instructions >> but I have no reason to keep Pulse. I just tried: > > I'm willing to tolerate PulseAudio on my desktop/laptop because it does > conveniently share the sound card between applications and allows me to > re-route applications between sound interfaces (something JACK does not > do well). > > I have a Raspberry Pi 3 which spends most of its day with a RTL2832 SDR > stick plugged in decoding DAB+: I tried PulseAudio there (since it > insisted on coming along for the ride), but found it just wanted to > "stutter" its way though, making things unlistenable. > > PortAudio applications refused to talk to the on-board sound directly, > so I wound up using JACK, which is working well enough now. > >> cmd: '/usr/bin/mpg123 --output alsa "/data/mp3/pink_floyd/1 - Studio >> Albums/1979 - The Wall/CD 2/Comfortably Numb.mp3" ' >> >> Which I thought I'd tried before, but that was before changing the >> group. Didn't hear anything but nothing in the Apache error log >> either. lsof should show the mp3 file open I think. Or maybe ps ax. >> Could be something in Apache's security but it's calling my CGI >> program OK. Oh, I'm calling mpg123 from a system() call and not >> checking the return, I was rushing it. > > Easy enough to forget that. Also, beware of command line injection with > your `system()` calls. An internal trusted network reduces the risk > quite a bit, but it's worth being paranoid here. > >> The eventual machine will probably be a Raspberry Pi that will get >> used for other things but not at the same time. I like having it on >> the web (NATed LAN actually) because there are phones, Kindles. >> computers in the house which could all control it. That part's mostly >> written, trying to actually hear audio was the last part. I have just >> over 10k MP3 files, but my loader will scan them and make web pages. >> In about 1/2 a second on this nvme SSD so it's painless to generate. >> I'm into writing these recursive directory climbers in c sometimes. > > Yep, well, one thing you might run into with a Raspberry Pi… some > software, notably anything that uses PortAudio (e.g. Audacity), last > time I tried it a few months back, would _not_ talk to the on-board > sound interface via ALSA directly. > > https://www.raspberrypi.org/forums/viewtopic.php?t=276247#p1750552 > > I haven't had the time to debug it further, but it's related to changes > in the ALSA kernel driver used. Other audio devices like > `snd-usb-audio` are not affected. > > `libao`-based stuff like `mpg123` may be fine. If you're not doing any > other "audio"-related things, again, you probably don't need PulseAudio. > If you find your program isn't finding the on-board sound card, JACK > may work, but then again, I've also never tried that in a CGI context. > >> Oh, Australia, land of radio astronomy. I'm ab1jx. Haven't been on >> the air in 10 years or so but I keep the license up. > > Heh, probably not in my neck of the woods (NW Brisbane). You'd never > hear E.T. over the top of 10000 el cheapo switch-mode wall warts, solar > inverters, traffic lights and plasma television sets. VHF can be noisy > too being so close to Mt. Coot-tha: I've accidentally tuned into ABC > Classic FM with a plain analogue amplifier (yaay for accidental slope > detection!) more times than I care to count, > -- > Stuart Longland (aka Redhatter, VK4MSL) > > I haven't lost my mind... > ...it's backed up on a tape somewhere. > -- ------------- Education is contagious. _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
