From: Craig H. <cr...@gu...> - 2005-07-05 23:23:30
|
Hi Seth, best place for these types of questions is on the gumstix-users mailing list, which I'm cc'ing for followups. I'll answers in between your questions below: On Jul 2, 2005, at 2:48 PM, Seth Cameron wrote: > I've spent many days trying to make sense of the sound system for > AudioStix, > and unfortunately I'm stuck at this point. > > I've learned what I could about OSS and the ioctl() calls that use > soundcard.h. I've had some success with this on documented features. > > I believe the reason I am getting poor microphone recording quality > is that > the +20 dB mic boost is not on and not accessible using aumix (OSS). That feature is accessible through aumix using the -i "input gain" feature. -i 100 will turn on boost; -i 0 will turn it off. To set the gain on MIC or LINEIN sources, use the MIC or LINEIN specific gain options in aumix. > Other programs that appear related to our gumstix platform are: > > ac97_codec.h / .c > pax-ac97.h / .c > pxa-audio.h / .c > > I can see that some patches have been added that define MICBOOST, > etc., but > I have no idea how to use this code, nor can I find any > documentation or > sample code that make calls to functions found in these files. aumix works :) > Do you know how to use these ac97 files? Those files are part of the kernel drivers. You just need to load the module, then you can use ioctls on /dev/dsp to control stuff. > Are they part of a library with an API? They are part of the OSS AC97 driver. > What is loaded with modprobe pxa-97? The pxa-ac97 driver. > Is there anywhere I can find some help or examples using the > UCB1400 with > Linux? You don't really need to know normally that there's a usb1400 under the hood -- you just interface with the OSS system, and it handles the details for you. Lots of OSS samples out there -- download more or less any linux audio app and you'll see how it accesses the sound subsystem and communicates with it. C |
From: paul <pos...@pa...> - 2005-07-06 10:33:05
|
Craig Hughes wrote on 7/6/2005 1:22 AM: > > You don't really need to know normally that there's a usb1400 under > the hood -- you just interface with the OSS system, and it handles > the details for you. Lots of OSS samples out there -- download more > or less any linux audio app and you'll see how it accesses the sound > subsystem and communicates with it. > > C Just a short question re alternative sound system: I read somewhere that with kernel 2.6.12 the pxa255 driver will be official part of ALSA. Is this true and will be available for gumstix too? Thanks, Paul |
From: Craig H. <cr...@gu...> - 2005-07-06 19:42:51
|
I don't believe it actually made it into 2.6.12, but there is a patch out there for pxa255 ac97 support in ALSA. I haven't had a chance to play with it yet, but it probably works OK. Might need some patches for the non-standard stuff in the ucb1400, but that should be pretty easy to merge in. C On Jul 6, 2005, at 3:32 AM, paul wrote: > Craig Hughes wrote on 7/6/2005 1:22 AM: > > >> >> You don't really need to know normally that there's a usb1400 >> under the hood -- you just interface with the OSS system, and it >> handles the details for you. Lots of OSS samples out there -- >> download more or less any linux audio app and you'll see how it >> accesses the sound subsystem and communicates with it. >> >> C >> > > Just a short question re alternative sound system: I read somewhere > that with kernel 2.6.12 the pxa255 driver will be official part of > ALSA. Is this true and will be available for gumstix too? |
From: Darren G. <ts...@ya...> - 2005-07-10 23:25:37
|
Unless you have a reason to learn the specifics of OSS or ALSA, I recommend using PortAudio instead. It's cross-platform, has a very easy to use API, and comes with lots of examples. http://www.portaudio.com/ On Jul 5, 2005, at 4:22 PM, Craig Hughes wrote: > Hi Seth, > > best place for these types of questions is on the gumstix-users > mailing list, which I'm cc'ing for followups. I'll answers in > between your questions below: > > > On Jul 2, 2005, at 2:48 PM, Seth Cameron wrote: > > >> I've spent many days trying to make sense of the sound system for >> AudioStix, >> and unfortunately I'm stuck at this point. >> >> I've learned what I could about OSS and the ioctl() calls that use >> soundcard.h. I've had some success with this on documented features. >> >> I believe the reason I am getting poor microphone recording >> quality is that >> the +20 dB mic boost is not on and not accessible using aumix (OSS). >> > > That feature is accessible through aumix using the -i "input gain" > feature. -i 100 will turn on boost; -i 0 will turn it off. To set > the gain on MIC or LINEIN sources, use the MIC or LINEIN specific > gain options in aumix. > > >> Other programs that appear related to our gumstix platform are: >> >> ac97_codec.h / .c >> pax-ac97.h / .c >> pxa-audio.h / .c >> >> I can see that some patches have been added that define MICBOOST, >> etc., but >> I have no idea how to use this code, nor can I find any >> documentation or >> sample code that make calls to functions found in these files. >> > > aumix works :) > > >> Do you know how to use these ac97 files? >> > > Those files are part of the kernel drivers. You just need to load > the module, then you can use ioctls on /dev/dsp to control stuff. > > >> Are they part of a library with an API? >> > > They are part of the OSS AC97 driver. > > >> What is loaded with modprobe pxa-97? >> > > The pxa-ac97 driver. > > >> Is there anywhere I can find some help or examples using the >> UCB1400 with >> Linux? >> > > You don't really need to know normally that there's a usb1400 under > the hood -- you just interface with the OSS system, and it handles > the details for you. Lots of OSS samples out there -- download > more or less any linux audio app and you'll see how it accesses the > sound subsystem and communicates with it. > > C > > > > ------------------------------------------------------- > SF.Net email is sponsored by: Discover Easy Linux Migration Strategies > from IBM. Find simple to follow Roadmaps, straightforward articles, > informative Webcasts and more! Get everything you need to get up to > speed, fast. http://ads.osdn.com/?ad_id=7477&alloc_id=16492&op=click > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |
From: Seth C. <se...@ca...> - 2005-07-11 00:20:31
|
Thanks for the portaudio link Darren. It looks interesting... Here is some knowledge I've gained regarding audio input with AudioStix. (As best I can discern, information posted from Craig has not been quite correct, but he was probably responding from memory.) Using aumix: Command / UCB1400 Register / Value written -i 100 -> 0x1c -> 0x0f0f = Max input gain (whether mic or line input) (+21.5 db) -i 0 -> 0x1c -> 0x8000 = Min input gain (all mute) -m 100 -> 0x0e -> 0x0040 = Mic preamp enabled (+20 dB) -m 0 -> 0x0e -> 0x0000 = Mic preamp disabled -l R -> 0x1a -> 0x0404 = Select line in for recording (Stereo recording, mic preamp bypassed) -m R -> 0x1a -> 0x0000 = Select mic in for recording (Left mono recording, Right channel copied from Left) -v 0-100 -> Master volume control I do not think that separate left volume/right volume control (balance) is possible using aumix without the ncurses interface. Is that true? Also, recording using brec should be done stereo even though the mic is mono. Mono settings with brec will write an incorrect .wav header and only record for 1/2 as long as requested. This brings me back my original query about decent quality microphone recordings. I've been able to make reasonable recordings from line in CD sources, but all of my attempts at microphone recordings have significant hiss and poor gain. (Similar to the type of voice recordings one can make with, for example, an IPAQ using the built-in mic.) Has anyone had success making good S/N microphone recordings? If not, my conclusion at this point is the that the preamp on the UCB1400 is crap, or significant digital noise is creeping into the audio circuitry, probably both. I'm looking at using a separate battery powered mic preamp, but the smallest I can find is bigger than gumstix and requires 9 V. :-) So much for miniaturization.... - Seth |
From: Darren G. <ts...@ya...> - 2005-07-11 18:08:45
|
On Jul 10, 2005, at 5:24 PM, Seth Cameron wrote: > This brings me back my original query about decent quality microphone > recordings. I've been able to make reasonable recordings from line > in CD > sources, but all of my attempts at microphone recordings have > significant > hiss and poor gain. What kind of mic are you using? Is it fairly high output, i.e. is the sensitivity > 20mV/Pa > I'm looking at using a separate battery powered mic preamp, but the > smallest > I can find is bigger than gumstix and requires 9 V. :-) So much for > miniaturization.... I experimented with an electret condenser capsule from radio shack and a Canakit mic pre: http://www.canakit.com/Contents/Divisions/Div_25.asp I got a LOT more gain from the external preamp. |
From: Craig H. <cr...@gu...> - 2005-07-12 04:30:02
|
On Jul 10, 2005, at 5:24 PM, Seth Cameron wrote: > (As > best I can discern, information posted from Craig has not been quite > correct, but he was probably responding from memory.) Darn that abuse I put my brain through in college -- memory's never quite been the same since. C |
From: Craig H. <cr...@gu...> - 2005-07-12 04:30:04
|
On Jul 10, 2005, at 5:24 PM, Seth Cameron wrote: > I do not think that separate left volume/right volume control > (balance) is > possible using aumix without the ncurses interface. Is that true? I believe it is -- certainly I implemented left/right balance, bass/ treble boost and I think maybe one or two other similar things in the ucb1400 driver, and the only way I had to test was using aumix -- so I think it is possible. > Also, recording using brec should be done stereo even though the > mic is > mono. Mono settings with brec will write an incorrect .wav header > and only > record for 1/2 as long as requested. Yeah, ucb1400 seems to be doing something "special" with the duped mic input or something, and I think it confuses brec somehow. Not sure what's going on exactly. > This brings me back my original query about decent quality microphone > recordings. I've been able to make reasonable recordings from line > in CD > sources, but all of my attempts at microphone recordings have > significant > hiss and poor gain. (Similar to the type of voice recordings one > can make > with, for example, an IPAQ using the built-in mic.) > > Has anyone had success making good S/N microphone recordings? > > If not, my conclusion at this point is the that the preamp on the > UCB1400 is > crap, or significant digital noise is creeping into the audio > circuitry, > probably both. Hmm, testing I was doing sounded OK -- not audiophile OK since I wasn't listening for that, but "sounds at least as good as I'd expect from my $10 microphone" OK. It wouldn't substantially surprise me if the pre-amp were lousy on the usb1400, which seems like the most likely problem if you say line-in input is OK. Might be useful to look at a sonogram of the noise though, to see if it looks like there's a dominant frequency which might point to noise leaking. > I'm looking at using a separate battery powered mic preamp, but the > smallest > I can find is bigger than gumstix and requires 9 V. :-) So much for > miniaturization.... I think while I was looking around at mics for testing, that I saw some reasonably small powered mics. Could easily be that the websites I was looking at though were just showing the mic head and not showing the giant battery pack box... I'll see if I can find those sites again to provide links when I get back online here... C |
From: Craig C. <cra...@gm...> - 2005-07-13 17:11:39
|
Just something to keep in mind, I've noticed the audiostix is very noisy when using the usb interface, but gets much quieter if you don't use it. Craig Casey On 7/11/05, Craig Hughes <cr...@gu...> wrote: > On Jul 10, 2005, at 5:24 PM, Seth Cameron wrote: >=20 > > I do not think that separate left volume/right volume control > > (balance) is > > possible using aumix without the ncurses interface. Is that true? >=20 > I believe it is -- certainly I implemented left/right balance, bass/ > treble boost and I think maybe one or two other similar things in the > ucb1400 driver, and the only way I had to test was using aumix -- so > I think it is possible. >=20 > > Also, recording using brec should be done stereo even though the > > mic is > > mono. Mono settings with brec will write an incorrect .wav header > > and only > > record for 1/2 as long as requested. >=20 > Yeah, ucb1400 seems to be doing something "special" with the duped > mic input or something, and I think it confuses brec somehow. Not > sure what's going on exactly. >=20 > > This brings me back my original query about decent quality microphone > > recordings. I've been able to make reasonable recordings from line > > in CD > > sources, but all of my attempts at microphone recordings have > > significant > > hiss and poor gain. (Similar to the type of voice recordings one > > can make > > with, for example, an IPAQ using the built-in mic.) > > > > Has anyone had success making good S/N microphone recordings? > > > > If not, my conclusion at this point is the that the preamp on the > > UCB1400 is > > crap, or significant digital noise is creeping into the audio > > circuitry, > > probably both. >=20 > Hmm, testing I was doing sounded OK -- not audiophile OK since I > wasn't listening for that, but "sounds at least as good as I'd expect > from my $10 microphone" OK. It wouldn't substantially surprise me if > the pre-amp were lousy on the usb1400, which seems like the most > likely problem if you say line-in input is OK. Might be useful to > look at a sonogram of the noise though, to see if it looks like > there's a dominant frequency which might point to noise leaking. >=20 > > I'm looking at using a separate battery powered mic preamp, but the > > smallest > > I can find is bigger than gumstix and requires 9 V. :-) So much for > > miniaturization.... >=20 > I think while I was looking around at mics for testing, that I saw > some reasonably small powered mics. Could easily be that the > websites I was looking at though were just showing the mic head and > not showing the giant battery pack box... I'll see if I can find > those sites again to provide links when I get back online here... >=20 > C >=20 >=20 > ------------------------------------------------------- > This SF.Net email is sponsored by the 'Do More With Dual!' webinar happen= ing > July 14 at 8am PDT/11am EDT. We invite you to explore the latest in dual > core and dual graphics technology at this free one hour event hosted by H= P, > AMD, and NVIDIA. To register visit http://www.hp.com/go/dualwebinar > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |
From: Craig H. <cr...@gu...> - 2005-07-14 18:04:39
|
Hmm, interesting -- that argues in favor of the digital noise hypothesis. C On Jul 13, 2005, at 10:11 AM, Craig Casey wrote: > Just something to keep in mind, I've noticed the audiostix is very > noisy when using the usb interface, but gets much quieter if you don't > use it. > > Craig Casey > > On 7/11/05, Craig Hughes <cr...@gu...> wrote: > >> On Jul 10, 2005, at 5:24 PM, Seth Cameron wrote: >> >> >>> I do not think that separate left volume/right volume control >>> (balance) is >>> possible using aumix without the ncurses interface. Is that true? >>> >> >> I believe it is -- certainly I implemented left/right balance, bass/ >> treble boost and I think maybe one or two other similar things in the >> ucb1400 driver, and the only way I had to test was using aumix -- so >> I think it is possible. >> >> >>> Also, recording using brec should be done stereo even though the >>> mic is >>> mono. Mono settings with brec will write an incorrect .wav header >>> and only >>> record for 1/2 as long as requested. >>> >> >> Yeah, ucb1400 seems to be doing something "special" with the duped >> mic input or something, and I think it confuses brec somehow. Not >> sure what's going on exactly. >> >> >>> This brings me back my original query about decent quality >>> microphone >>> recordings. I've been able to make reasonable recordings from line >>> in CD >>> sources, but all of my attempts at microphone recordings have >>> significant >>> hiss and poor gain. (Similar to the type of voice recordings one >>> can make >>> with, for example, an IPAQ using the built-in mic.) >>> >>> Has anyone had success making good S/N microphone recordings? >>> >>> If not, my conclusion at this point is the that the preamp on the >>> UCB1400 is >>> crap, or significant digital noise is creeping into the audio >>> circuitry, >>> probably both. >>> >> >> Hmm, testing I was doing sounded OK -- not audiophile OK since I >> wasn't listening for that, but "sounds at least as good as I'd expect >> from my $10 microphone" OK. It wouldn't substantially surprise me if >> the pre-amp were lousy on the usb1400, which seems like the most >> likely problem if you say line-in input is OK. Might be useful to >> look at a sonogram of the noise though, to see if it looks like >> there's a dominant frequency which might point to noise leaking. >> >> >>> I'm looking at using a separate battery powered mic preamp, but the >>> smallest >>> I can find is bigger than gumstix and requires 9 V. :-) So much for >>> miniaturization.... >>> >> >> I think while I was looking around at mics for testing, that I saw >> some reasonably small powered mics. Could easily be that the >> websites I was looking at though were just showing the mic head and >> not showing the giant battery pack box... I'll see if I can find >> those sites again to provide links when I get back online here... >> >> C >> >> >> ------------------------------------------------------- >> This SF.Net email is sponsored by the 'Do More With Dual!' webinar >> happening >> July 14 at 8am PDT/11am EDT. We invite you to explore the latest >> in dual >> core and dual graphics technology at this free one hour event >> hosted by HP, >> AMD, and NVIDIA. To register visit http://www.hp.com/go/dualwebinar >> _______________________________________________ >> gumstix-users mailing list >> gum...@li... >> https://lists.sourceforge.net/lists/listinfo/gumstix-users >> >> > > > ------------------------------------------------------- > This SF.Net email is sponsored by the 'Do More With Dual!' webinar > happening > July 14 at 8am PDT/11am EDT. We invite you to explore the latest in > dual > core and dual graphics technology at this free one hour event > hosted by HP, > AMD, and NVIDIA. To register visit http://www.hp.com/go/dualwebinar > _______________________________________________ > gumstix-users mailing list > gum...@li... > https://lists.sourceforge.net/lists/listinfo/gumstix-users > |