Linux-audio-user July 2014

linux-audio-user@lists.linuxaudio.org

89 participants
59 discussions

by James Stone

I've just done some quick testing of AVLinux vs. Ubuntustudio, and the performance of jackd is significantly worse on ubuntustudio.. On AVLinux, I can start up jack (0.121.3) with 32 frames, and CPU runs around 3%. On Ubuntu (jackd 1.9.10), I am getting 30%+ with the same settings. Checking top, I am getting pulseaudio at 30% and jackdbus at 20%.. Killing pulseaudio, jackdbus goes down to 13%, but this is still significantly worse than avlinux.. I'm wondering if it is due to differences in new vs. old jack, or if there is something else I can tweak? James

10 years, 8 months

Re: [LAU] music software for kids

by Fede

And the due on topic reply: http://soosck.wordpress.com/2010/12/09/open-source-music-games-linux/ Bye! -- Fede <federicogalland(a)gmail.com>

10 years, 8 months

DIY digital control surfaces

by Len Ovens

I seem to have gotten an itch to make some control surfaces for my home recording system. The first thing I find is that hardware is expensive and software is cheap (money wise, time is something else). Fewer pots and switches costs less and so they need to be multi-functional. This means momentary switches with coloured lights in them, rotary encoders, and motorized faders. So, how about a touch surface? 7inch android things don't cost much and have wireless and stuff... and play games when we are bored ;) with a touch surface you have to watch what you are doing all the time, real knobs and sliders let you feel. digital mixers use a mix of things... but no mouse that I have seen. Generally at least one touch screen though. It is used for all the stuff that is hard to use controls for. But also for remote control. The diy sites show the rotary encoders with light strips to show position, but I don't see this on the mixers... they give feedback through the touch screen instead. The encoder is $2, the light strip is $15. I am not sure what the interface is like, but it would seem simpler than a pot. Encoders are fine for starting from where I am and moving, but for some things a fader is still needed. If it is going to be used for more than one thing, it needs to be motorized. This doesn't seem too bad at $20 for the fader/motor combination.... but the support stuff has to be there too. It needs a motor driver, encoder and (so they say) touch sensing so the motor won't fight against your finger. There seem to be "brains" out there with switch and analog inputs with USB or midi ports. (and led outputs) Ya the stuff is all there. Some other ideas: for faders on a touch pad (screen or drawing pad or whatever) The point where the fader is right now does not matter, only that it can be moved in the right direction without jumping to whereever the finger first touches, tactile feel could be added plastic template that has slots where the faders are supposed to be. This would be cheap to try (compared to building just about anything) and I have wanted a drawing tablet to try other things anyway. For switches the keyboard has got to be the cheapest thing... only one thing is focus changes. Linux is very nice in recognizing and using new USB things. If I plug in a second keyboard, I now have two keyboards that do the same thing (mice work this way too). I want to use the second keyboard as direct input for my own program that takes key presses in and puts midi messages out to a jack port. In fact it may be an interesting tool to make a keyboard driver that uses one key to switch modes between midi mode and keyboard mode on the main keyboard even. (that strange flag key for example) Anyway, is there an easy way to grab a keyboard device before the system does? This looks to be /dev/input/event7. There is a utility called actkbd that reads this. And I guess it can run a script for any one key or just output to stdout the key press. Anyone have a better idea? -- Len Ovens www.ovenwerks.net

10 years, 8 months

Request for advice: remote Linux server playing audio on local Windows system

by Nikhil Nair

Hi, I'm pretty new to Linux audio, but a project I'm working on is going to need me to generate musical notes on a remote Linux server, in (near-)realtime (i.e. changing the sound output based on realtime events). I have basically no familiarity with MIDI etc., but the easiest interface I've found for the starting and stopping of notes, so far, is the FluidSynth API. That's not the issue, however: the trick is getting the audio back to my Windows machine with low-ish latency, and in reasonable quality. To add a little interest to the scenario..., my Windows machine is also behind NAT and a firewall. The ping round-trip time is under 30 ms, though, so I'm hoping latencies of around 200 ms might be possible. Just to make life more interesting, I'd rather not have to use X Windows at all on the remote machine, as I'm blind, and haven't even begun to think about the ins and outs of accessibility of a remote X server (and, frankly, would rather just not go there for now). (The application I'm working on may interest you, BTW: I'm converting financial data, particularly currency price charts, into soundscapes, for "visualising" recent price movements. If it were just a one-off, I could convert it into an audio file and download it; but, instead, I want it to be interacctive, so I can rewind through the image, step backward or forward frame by frame, etc. I'm going to have fun with this!) I've been considering a few methods of getting the audio to my Windows machine, but none of the options I've come up with so far seem to quite work as I want. Here's what I've considered. 1. Send audio to JACK, then send it to the Asterisk PBX via the App_Jack application; listen to the audio via a softphone on the Windows machine, connecting to the Asterisk server via SIP. Sound quality wouldn't be ideal - 8KHz mono - but I could live with that. Unfortunately, it looks like App_Jack doesn't successfully connect to a JACK server: a bug report was lodged about it over 3 years ago, marked severe, but doesn't seem to have been fixed as yet. 2. Send audio via Jack and a streamer (probably DarkIce) to an Icecast2 server; then use a media player such as WinAmp or MPlayer. The problem here is buffering: 10-20 seconds of latency just isn't acceptable for the realtime aspects of the project, and I don't know if there's a way to get a media player to do unbuffered playback (a quick Google search seemed to indicate not). 3. Use netJACK1 to play audio direct from JACK (that's the only one of the 3 networked-JACK solutions mentioned on the JACK website that's recommended for use over a WAN). Unfortunately, once I dug into this, it looks like the assumption is that the audio will be played on a Linux box: there doesn't seem to be any provision for having the Windows machine as the one doing the audio playing. I did have a quick look at netJACK2, but that seems to assume the two machines are on the same LAN - you don't even specify the IP address to connect to! 4. I wondered about using PulseAudio. However, that seems quite tricky to set up without X on the remote machine, and I'm not at all clear about the NAT traversal issue. 5. I also wondered about NAS: I gather it's very outdated, but it sounds like about what I'm after. However, I couldn't find a Windows download; and FluidSynth doesn't have a NAS interface, as far as I understand it. TiMidity does, though, so I'd just need to work out how to send it MIDI events from software... Tunneling through a forwarded port (using ssh) may help in some aspects, but I'm not sure. AT least, it adds an extra set of possibilities, as do VPNs. As you can see, I've been wracking my brains over this for a couple of days, and while I've felt I'm really close on more than one occasion, I've not quite got there. Any input would be very much appreciated! Alternatively, if there's a better place for me to be asking this question, a pointer would be very helpful. Cheers, Nikhil.

10 years, 8 months

"[...] realtime kernel [...] prepare for a future [...]" - [1]

by Ralf Mardorf

[1] http://lwn.net/Articles/572740/ Reawoken: http://marc.info/?l=linux-rt-users&m=140615962203369&w=2

10 years, 8 months

Re: [LAU] DIY acoustic absorbers?

by Moshe Werner

Hi Gabbe, To my understanding this would have a positive effect. There are actually some commercial products that are designed "your" way. But בתאריך 24 ביול 2014 09:21, "Gabriel Nordeborn" <gabbe.nord(a)gmail.com> כתב: > Time to revive this old thread... Thank you for all of your messages and > thoughts! After what feels like ages, I finally have time to start this > project for real. > > A question about low frequency absorption/bass traps: > > - One of the best ideas I've seen around for doing DIY bass traps is to > cut triangles from the rock wool, and then place the triangles in the > corners, from bottom to roof. I won't be able to do it that way just yet, > BUT, I wonder whether it would be an idea to just stack rock wool panels on > top of eachother in the corners, and achieve at least some low end > frequency absorption? This wouldn't cover the entire area of the corner, > but would still make some I guess. My monitors are very small and don't > produce a lot of low end, and I won't be recording a lot of bassy stuff > either, so maybe this could suffice as a starting point? See image attached. > > Thoughts? thanks again for all the info! > > > On Sun, May 25, 2014 at 10:07 PM, Moshe Werner <moshwe(a)gmail.com> wrote: > >> >> >> >> >> >> Hi, >> >>> >>> I recently moved to a new flat, and I've just got my studio properly >>> setup in one of the rooms. >>> >> Congrats! I hope we get a lot of your beautiful music out of this room:) >> >>> Problem is, the room is rather horrible acoustically. As this is the >>> room I've got to play with, I'm going to have to make the best of it >>> acoustically. >>> >>> So, my question is about DIY acoustic absorbers. I'm most likely looking >>> to build absorbers both for mid/hi-end (I'm thinking the classical rock >>> wool ones you place spaced out a bit form the walls) and for the lower end, >>> but I am very much open for suggestions. Here's some specs of my setup: >>> >> >>> - The room is roughly 3.60m wide, 3.40m long and 2.50m high. I think at >>> least one wall is concrete. >>> >> As first step I would consider to mix facing the narrow side of the room >> >> Plus always keep everything nice and symmetric. >> Also I would recommend to measure the room to see what problems you're >> dealing with. http://www.roomeqwizard.com/ is available for Linux AFAIK. >> >> - My mixing position/monitors is in the middle of the front wall. I sit >>> about 1.20m out from the wall. >>> >> Have you heard about the 38% rule? If not read up on this >> http://realtraps.com/art_room-setup.htm, also covers early reflection >> points. >> >> >> >>> - My monitors are small, a set of Adam A3X (so 3" elements I guess). It >>> basically gives very low bass response, so I can hear fairly OK down to >>> about 80hz, rapidly declining down to 60hz where there's nothing left. >>> >> Less low energy buildup, but as you mentioned you won't know whats down >> there so I would recommend you to treat for lower frequencies in case you >> upgrade your speakers in the future. >> >>> - I am not terribly dependent on mixing at high volumes, if that matters. >>> >> It matters a bit as there is less energy to be absorbed, but again I >> would treat properly just in case you want to listen with higher SPL's, so >> it doesn't totally change the EQ of your mix (anyway it will change with >> sound pressure level because of equal loudness contour >> <http://en.wikipedia.org/wiki/Equal-loudness_contour>) >> >>> >>> What I currently have is: >>> - Two large bookshelves along the wall right behind my mixing position >>> acting as diffusors. These go almost all the way up to the ceiling, and has >>> stuff unevenly stacked at different heights/positions in the bookshelf. >>> They cover 1.60m in the middle of the back wall. >>> >> I've got good experience with bookshelves in homestudios, given they >> aren't to close behind the listening position. >> >>> - I also have a fairly large carpet on the floor in the middle of the >>> room. It probably doesn't do that much, but maybe it does a little. >>> >> It does a little in preventing flutter echo of high frequencies. >> >>> >>> My question then is; are there any effective ways of acoustically >>> treating this room? Of course, given the topic of the e-mail, I'm very much >>> willing to do my own DIY solutions, if that's a viable option. What I have >>> been thinking is doing what I mention above; classical absorber "panels", >>> and bass traps. >>> >> I would treat the corners and early reflection points first. >> In a homestudio of a friend we filled the corners with rockwool made a >> wooden frame and covered them with fabric. >> Early reflection points can be treated with 10-15cm thick "classical >> absorber panels". >> For our live room we've done something else, we made wooden slat covered >> frames and filled the cavity with rockwool . >> I like what it does to the room as it doesn't make it dead but tames the >> response quite nicely. >> >> >>> But, before I start anything, I'd very much like input from people who >>> actually know what they're talking about (I'm looking at you on this list >>> ;) ). So, does anyone have thoughts/suggestions for me? Any recommended way >>> of doing this? >>> >>> Thank you very much for any help and any replies! >>> >> Best of luck! >> Moshe >> >> >> >

10 years, 8 months

Re: [LAU] A short story: from zero to recording the drums in a budget

by Burkhard

This thread was just what I needed. Thank you, Carlo and all! - Burkhard -------- Ursprüngliche Nachricht -------- Von: Carlo Ascani <carlo.ratm(a)gmail.com> Datum: An: Fons Adriaensen <fons(a)linuxaudio.org> Cc: linux-audio-user <linux-audio-user(a)lists.linuxaudio.org> Betreff: Re: [LAU] A short story: from zero to recording the drums in a budget 2014-07-22 10:23 GMT+02:00 Fons Adriaensen <fons(a)linuxaudio.org>: > > I've got a similar setup: 512M, Arch + windowmaker, > but can't get A3 to run on it in any usable way - it > just eats too much memory. Any tricks ?? > Not really, sorry. And honestly, the only thing I am able to do with so little ram is to record. No way I can do editing, and plugins neither. > Ciao, > > -- > FA > > A world of exhaustive, reliable metadata would be an utopia. > It's also a pipe-dream, founded on self-delusion, nerd hubris > and hysterically inflated market opportunities. (Cory Doctorow) > > _______________________________________________ > Linux-audio-user mailing list > Linux-audio-user(a)lists.linuxaudio.org > http://lists.linuxaudio.org/listinfo/linux-audio-user -- Carlo Ascani | carlorat.me skype: carloratm irc: carloratm@freenode _______________________________________________ Linux-audio-user mailing list Linux-audio-user(a)lists.linuxaudio.org http://lists.linuxaudio.org/listinfo/linux-audio-user

10 years, 8 months

sd card / firewire

by rosea.grammostola

Hi, I need a new laptop, not specific for audio but would be nice to be able to run an pro-audio card. I'm doubting between a lenovo t400 and a x220. Would it be possible to use firewire on the x220 (via an sd card -> firewire converter)? Regards, /r

10 years, 8 months

OT Microphone recommendation

by Ivan K

Well, I ordered my microphone preamp, now I need a microphone. Based on the archives of this list and my budget, I identified three. What I mostly will be doing is: (1) Recording voice, either speaking or singing (2) Recording acoustic instruments (classical guitar, clarinet) (3) Recording chamber music. So the three microphones are: (a) Shure SM57 (Is there a difference between the SM57 and SM57-LC?) (b) Shure SM58 (Though which one: the SM58-LC, SM58-CN or SM58S ?) (c) CAD gxl 2200 large diaphragm condenser $60 Just from my naive understanding, the SM57 seems like it might be the best "general purpose" microphone for my needs. Do people have advice or other recommendations? Thanks. Eventually I will buy a second microphone for stereo recording.

10 years, 8 months

Phone to computer adaptor

by Bob van der Poel

I currently have a "skype" phone connected to USB which works just fine to make calls. Only problem is that the cord is short :) and the quality is not the greatest. So, can I connect a regular POTS phone via a USB thing? What are they called and do they work with Linux? I assume that the skype phone just acts like a soundcard ... same with what I want? Thanks. -- **** Listen to my FREE CD at http://www.mellowood.ca/music/cedars **** Bob van der Poel ** Wynndel, British Columbia, CANADA ** EMAIL: bob(a)mellowood.ca WWW: http://www.mellowood.ca

10 years, 8 months

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Linux-audio-user July 2014