mbrennwa/mataa

mataa's Issues

[Suggestion] Low frequency loudspeaker impedance magnitude fit

To test if you consider it worthwhile.
A simplified model of impedance magnitude and a function to fit the model parameters to measured data.
The fit seems to be not excellent but good enough to get usable Thiele-Small parameters.

function [mag] = impedance_speaker_model (f,params)

Rdc=params(1);
f0=params(2);
Qe=params(3);
Qm=params(4);
Le=params(5);

w0 = 2pif0;
w = 2pif;

% low-frequency impedance (resonance peak, LCR part):
Res = Rdc*Qm/Qe;
Ces = Qe/w0/Rdc;
Les = 1/w0^2/Ces;

ZCes = 1./(iwCes);
ZLes = iwLes;
Zlow = 1 ./ ( 1/Res + 1./ZCes + 1./ZLes );

% total impedance:
Z = Rdc + w * Le + Zlow;
mag = abs (Z);

endfunction

function [Rdc,f0,Qe,Qm,Le] = impedance_fit_speaker (f,mag)

% guess starting value for Rdc:
Rdc = min (mag);

% guess starting values for f0:
u = diff (mag);
F = ( f(1:end-1) + f(2:end))/2;
[u1,k1] = max (u); [u2,k2] = min (u);
if ~exist ('f0','var')
f0 = (F(k1)+F(k2))/2;
endif
clear F

% estimate impedance at f0:
[u,k] = min(abs(f-f0));
Rmax = mag(k);
clear u
clear k

% estimate f1 and f2:
k = find(f<f0);
[u,k] = min(abs(mag(k)-sqrt(Rmax*Rdc)));
f1 = f(k);
clear u
clear k
f2 = f0^2/f1;

% guess starting values for Qe and Qm:
Qm = f0/(f2-f1)*sqrt(Rmax/Rdc);
Qe = Qm / (Rmax/Rdc-1);

% starting value for Le
Le = 0;

clear f1
clear f2

inputparams = [Rdc,f0,Qe,Qm,Le];
[f,p,cvg,iter,corp,covp]=leasqr(f,mag,inputparams,"impedance_speaker_model");
Rdc=p(1);
f0=p(2);
Qe=p(3);
Qm=p(4);
Le=p(5);

endfunction

Issue running RC high-pass filter

Just starting with the example RC high-pass filter...

w = mataa_signal_generator('white',96000,0.3);
h = mataa_measure_IR(w,96000);
Creating / resetting to MATAA default settings (command: save -mat ..mataa_settings.mat mataa_settings ; )...

scalar structure containing the fields:

plotColor = b
plotWindow_IR =  1
plotWindow_SR =  2
plotWindow_FR =  3
plotWindow_CSD =  4
plotWindow_ETC =  5
plotWindow_HD =  6
plotWindow_impedance =  7
plotWindow_TBES =  8
openPlotAfterSafe =  1
channel_DUT =  1
channel_REF =  2
interchannel_delay = 0

...done.
error: 'latency' undefined near line 73 column 67
error: evaluating argument list element number 3
error: called from:
error: C:/Users/findelic/Desktop/mataa-User/mataa_tools\mataa_measure_IR.m at line 73, column 18

compile warnings, format specifier

When compiling TestTonePA19.c as per the instructions in the README, I get warnings on lines:
279, 286, 373, and 383 saying tht format %d expects an int but gets an long unsigned int.

The format for all four should be changed to %lu

Compiling TestDevicesPA19.c I get warnings on lines 140 and 175, too many arguments for format
both printf statements need to be fixed.

Issues running with Matlab R2018b (9.5.0.944444)

Error: File: mataa_measure_signal_response.m
Line: 355 Column: 50
Incorrect use of '=' operator.
To assign a value to a variable, use '='.
To compare values for equality, use '=='.

mataa/mataa_tools/mataa_measure_signal_response.m

Line 355 in 4c8f5f8

dut_out_unit{k} = dut_in_unit{k} = '???';

solved by changing to:

    dut_in_unit{k} = '???';
    dut_out_unit{k} = '???';

Update mataa_impedance_fit_speaker.m line 138

Hello Mathias,
I would follow the standard procedure of forking, modifying and making a pull request, but I believe all is needed is simply to change line 138 in mataa_impedance_fit_speaker.m, writing mataa_impedance_speaker_model_LR2 instead of mataa_impedance_speaker_model.
Best regards,
Esteban

ld cannot find -lasound

This error occurs when compiling TestTonePA19.c and TestDevicePA19.c per the instructions in the README
gcc -lrt -lasound -lpthread -o TestTonePA19 TestTonePA19.c libportaudio.a
...
/usr/bin/ld: cannot find -lasound
collect2: error: ld returned 1 exit status

Are there other files I need to copy from elsewhere, or paths I need to define?

Note this is regardless of the printf format warnings mentioned in my other issue.
I am using Ubuntu 18.10 in a VM on Windows 10.
and using freshly downloaded MATAA and portaudio files.
I am following the README as written (i.e. with no assumptions made by me.)

[question] - how to calibrate sound card and setting output level

Hello Matt. Regarding your MATAA software I have a couple of questions:

1. how can I specify output level when emitting a signal like this:
   s = mataa_signal_generator(’square’,96000,0.1,1000);
   ​res = mataa_measure_signal_response(s,96000);

to say 1Vpp..?

2. how can I calibrate the output signal of my sound card, so that when doing the previous, signal would be exactly 1Vpp, and not more, not less??

Thanks!
I really hope this software how help me with the analisys of my tube amp!

Btw, what external sound card would you recommend? I only have the integrated one of my laptop. And that seems to only support 44100 sample rate..