Linux apps useful for speaker/amplifier analsys

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#3
Also, 'ams' has pink noise generator which may be useful (especially in use with japa - last one works as 'anti-pinknoise' filter, when 'Resp' is set to 'Prop'):

http://alsamodular.sourceforge.net/

Also, you can look at 'Room EQ Wizard':

http://homepage.ntlworld.com/john.mulcahy/roomeq/index.html

It is java app, but free and run under Linux.

Aha, now it is time to ask 🙂 Has anybody thoughts how to measure an own speaker frequency respose (something like justMLS under win32, i.e. before first reflections come to microphone)?
 
#4
I have also been looking for a MLS-based measurement app. Maybe one needs to be written. :bawling:

So far I have measured responses with a frequency sweep (that has pauses to mark frequency points), and analyzed it in audacity with logarithmic amplitude scale. Spectrogram view gives some idea of distortion, but nothing accurate.
 
#8
jcx said:
http://scilabsoft.inria.fr/

MatLab workalike open source math software duplicates the functionality of most MatLab ToolBoxes - what real engineers use for system identification/signal processing - and has .wav i/o

for loudspeaker testing you should at least cruise Klippel's site to see what can be done

http://www.klippel.de/background/introduction.asp
Click to expand...

There are plenty science and/or plotting apps. There isn't one ready for use for DIY-measurements. This is the only reason I was forced to try write something useful myself.

Of cource, I mean Linux/open-source world.

As for "what can be done" - I know without Klippel, there are plenty things 🙂
 
#12
QLoud is updated up to v.0.15

QLoud is updated up to v.0.15. Changes:

- a crash (hitting "Plot" with empty IR list) is fixed,
- pickers values are rounded now,
- multiple minor fixes and cleanup,
- now "Window, msec" is a time from IR peak to cutted reverberations, which is more intuitive, I think (earlier it was equal to applied window width itself).

Direct screenshot links:

- main window with few SPL plots: http://gaydenko.com/qloud/screenshots/shot01.png
- IR-power plot: http://gaydenko.com/qloud/screenshots/shot02.png
 
#16
anli said:


JACK-server is de-facto Linux standard audio interface. QT4 branch is more than one year(!) old.
Click to expand...

That just means it'll hit the stable branch in another four years 😀

I did try Jack from source. Had some CPU gobbling issue I couldn't track down, so I went back to ALSA.

If there's a patch to simulate a Jack server, like ALSA has fo OSS, I haven't found it.
 
#17
Geek said:
...If there's a patch to simulate a Jack server, like ALSA has fo OSS, I haven't found it.
Click to expand...

It is impossible. JACK server isn't a driver, it is a way applications communicate with each other.
If you are interested in linux audio, you can try these mailing lists:

The Linux Audio Developers' Mailing List <linux-audio-dev@music.columbia.edu>
A list for linux audio users <linux-audio-user@music.columbia.edu>

(I don't remember join-to-list points, just google)
 
#18
QLoud - distortions plotting is added!

QLoud is updated to v.0.17. Find it here:

http://gaydenko.com/qloud/

Harmonics (distortions) plotting is added. Direct screenshot link to harmonics plot:

http://gaydenko.com/qloud/screenshots/shot03.png

If you have a sound card with good DAC and ADC, you can plot harmonic
distortions for another audio equipment, say, for your power amplifier -
cited screenshot has also harmonics plot for loopbacked sound card.
 
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