Re: [Libmls0-developers] RE: libmls-0.3 released

[Daniel S. <ds...@ho...>]

> =20
> I have however had the time to look at the released version of libmls1,=
=20
> and I have some comments.=20
> First, that it compiles under Mandrake 10.0 and Gentoo Linux.=20
> But, I'm having trouble compiling the code in cvs.=20
> Is it just me or should it work?=20
>

What kind of errors do you get? Of course it should compile, it does=20
compile without problems on my fc1 system.

> I also think the mra/sra applications are a little bit more than=20
> examples, at least when I'm done with them, and should be compiled and=20
> installed as default.=20

I see libmls as a library. I think that only simple applications should=20
be distributed with the library.

If you decide to extend the sra and mra applications I think that you=20
should put them in a separate module in the cvs and release them as a=20
separate tarball on the libmls website. Also, I really think we need a=20
very simple example since the example is the only documentation available.

/Daniel

---
http://sumpan.com

> I will change the command line parameter processing to getopt once I=20
> can compile the code in cvs. Then mra/sra should support everything=20
> libmls supports.=20
> =20
> I also now think that the impedance measurement tools frd2zma/zma2rlc=20
> should be removed, as these are generic tools, and can be used with any=
=20
> response measurement software. I have already incorporated these in my=20
> lsp library and I think they fit better there.=20
> =20
> /Daniel=20
> =20
>=20
>>=20
>>From: Daniel Sundberg <ds...@ho...>=20
>>Date: 2004/06/23 on PM 05:07:55 GMT+02:00=20
>>CC: lib...@li...=20
>>=C4mne: Re: [Libmls0-developers] RE: libmls-0.3 released=20
>>=20
>>Hi again!=20
>>=20
>>As always, one more thing. Daniel: it would be really nice if you=20
>=20
> could =20
>=20
>>provide a very short summary of what the different programs in you =20
>>lsputils actually does.=20
>>=20
>>"FRD to ZMA transformer" is not very useful information if you do not =20
>>know what frd and zma is. Of course I might look at the source, which=20
>=20
> I =20
>=20
>>will do anyway, and find out for myself, but a very short and quick =20
>>description will get me started a little quicker...:-)=20
>>=20
>>/Daniel=20
>>=20
>>=20
>>Daniel Sundberg wrote:=20
>>
>>>>>I have two questions: what is FHT? Fast Hamahard Transform?=20
>>>>
>>>>
>>>>
>>>>Fast Hadamard Transform, I think.=20
>>>>
>>>>
>>>>
>>>>>Daniel: did libmls use FHT before and now uses FFT?=20
>>>>
>>>>
>>>>
>>>>Yes, I basically replaced the FHT transform routines from Anders =20
>>>>Torger with FFTW.=20
>>>>I'm not sure if it would be more correct to call it DFT or FFT=20
>=20
> though, =20
>=20
>>>>since it's not N^2 length.=20
>>>>But FFTW must use some kind of FFT method anyway since it's so=20
>=20
> fast.=20
>=20
>>>=20
>>>Well, I just realized I have studied this in a signal processing =20
>>>course... I actually have access to very detailed theory on this =20
>>>subject...:-)=20
>>>=20
>>>
>>>>The above also means that the information in the README file is =20
>>>
>>>=20
>>> > longer correct. There is no mic calibration mode anymore, and=20
>>> > there must be a loop from the output to the left (reference=20
>>> > channel) and the right channel must be used for measurements.=20
>>> >=20
>>>=20
>>>If this is the case we really need some updated documentation,=20
>=20
> could you =20
>=20
>>>please patch the README and we will make an updated release.=20
>>>=20
>>>
>>>>And then to my attachment:=20
>>>>I have attached the loudspeaker library that I'm working on.=20
>>>>I plan to put it on savannah.gnu.org or sourceforge soon, but I=20
>=20
> would =20
>=20
>>>>like to have some comments on the code before I do that.=20
>>>>
>>>
>>>=20
>>>I will try to take a look at this and of course comment if I feel=20
>=20
> the =20
>=20
>>>need to...=20
>>>=20
>>>
>>>>My goal with this library, is that it, together with libmls,=20
>=20
> should be=20
>=20
>>>>complete enough to replace CALSOD, MLSSA etc. with open source=20
>=20
> tools.=20
>=20
>>>>I also want to keep it as portable as possible.=20
>>>>
>>>
>>>=20
>>>It's all about the GUI today, you know...:-)=20
>>>=20
>>>Regards=20
>>>=20
>>>Daniel Sundberg=20
>>>=20
>>>=20
>>>
>>>>The intended audience is:=20
>>>>Developers of measurement or loudspeaker software like e.g.=20
>=20
> gspeakers.=20
>=20
>>>>Advanced users that would like complete freedom in choosing design =20
>>>>methodology.=20
>>>>
>>>>So it is both a library, to satisfy the first group.=20
>>>>And a set of command line utilities using the above library, to =20
>>>>satisfy the second group.=20
>>>>
>>>>To make it both as portable and as easily scriptable/customizable=20
>=20
> as =20
>=20
>>>>possible the command line utilities should only do one operation=20
>=20
> each =20
>=20
>>>>and the only thing requiring potentially hard to port or compile=20
>=20
> GUI =20
>=20
>>>>code should be the waveform viewer.=20
>>>>
>>>>Implemented at the moment is:=20
>>>>*FRD/ZMA file I/O=20
>>>>*Import of ddb speaker data base.=20
>>>>  As generated and used by:=20
>>>>  http://www.danbbs.dk/~ko/ubmodel.htm=20
>>>>*Partial implementation of the loudspeaker model in:=20
>>>>  http://www.hal-pc.org/~bwhitejr/btsmodel.zip=20
>>>>  found here:=20
>>>> =20
>=20
> http://www.geocities.com/loudspeakerguru/Speaker_Design_Equations.html=20
>=20
>>>>*Standard filter generator=20
>>>>*Ladder filter simulator with file I/O=20
>>>>*FRD waveform viewer=20
>>>>
>>>>The waveform viewer can use plotutils or gnuplot and it can=20
>=20
> display =20
>=20
>>>>the results from mra/sra.=20
>>>>It doesn't require plotutils to compile and it should be very easy=20
>=20
> to =20
>=20
>>>>port to other platforms or to embed in other applications.=20
>>>>
>>>>So most of the boring infrastructure things are at least usable=20
>=20
> and =20
>=20
>>>>lots of fun remains:=20
>>>>Filter/box optimization, spice like simulator and other box types=20
>=20
> (tl, =20
>=20
>>>>horn, etc.).=20
>>>>
>>>>When mra/sra has been updated with a bit more options (getopt) it =20
>>>>would be very easy to create a graphical front end that would just =20
>>>>launch mra and pass the results to resgraph (the waveform viewer).=20
>>>>
>>>>There are some example scripts in the script directory,=20
>>>>both for using plotutils and gnuplot.=20
>>>>
>>>>Regards,=20
>>>>Daniel W=20
>>>>
>>>>
>>>>
>>>>>From: Daniel Sundberg <ds...@ho...>=20
>>>>>Date: 2004/06/22 ti AM 11:11:57 GMT+02:00=20
>>>>>To: lib...@li...=20
>>>>>=C4mne: Re: [Libmls0-developers] RE: libmls-0.3 released=20
>>>>>
>>>>>Hi!=20
>>>>>
>>>>>I have two questions: what is FHT? Fast Hamahard Transform?=20
>>>>>
>>>>>Daniel: did libmls use FHT before and now uses FFT? I am afraid I =20
>>>>>have not been looking very close at the source code lately=20
>=20
> (mostly =20
>=20
>>>>>since I do not own a decent measurement microphone).=20
>>>>>
>>>>>Also, when some of you start to work on a sample application it=20
>=20
> might =20
>=20
>>>>>be a good idea to create a separate module in the cvs or create a=20
>=20
> new =20
>=20
>>>>>project.=20
>>>>>
>>>>>Regards=20
>>>>>
>>>>>Daniel Sundberg=20
>>>>>
>>>>>
>>>>>dan...@br... wrote:=20
>>>>>
>>>>>
>>>>>>Hi Scott=20
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>A little while ago Daniel talked about replacing the FHT with =20
>>>>>>>another scheme to generate the impulse response, which appears=20
>=20
> to =20
>=20
>>>>>>>have been done. Can you confirm that it is as fast as the FHT?=20
>>>>>>
>>>>>>
>>>>>>
>>>>>>I don't know if it's as fast as FHT, it's certainly fast enough=20
>=20
> for =20
>=20
>>>>>>desktop computers. I have no idea how they do it, but fftw=20
>=20
> doesn't =20
>=20
>>>>>>seem to be that much slower for n^2-1 fft lengths than n^2=20
>=20
> lengths.=20
>=20
>>>>>>
>>>>>>
>>>>>>>Does the correlation still create a perfect unit response as it =20
>>>>>>>should with the MLS?=20
>>>>>>
>>>>>>
>>>>>>
>>>>>>I'm not sure what you mean with a perfect unit response. But I'm =20
>>>>>>sure the new scheme is much more accurate than the FHT. I have =20
>>>>>>compared the results from the sweep mode with the MLS mode and=20
>=20
> they =20
>=20
>>>>>>are the same.=20
>>>>>>
>>>>>>The problem with FHT MLS is that you assume that the soundcard =20
>>>>>>doesn't degrade the signal at all. It's in fact even more=20
>=20
> sensitive =20
>=20
>>>>>>to this than you might think. Even with an almost perfectly flat =20
>>>>>>freqency response you will still not get good results with the=20
>=20
> FHT. =20
>=20
>>>>>>I think the FHT should be viewed as a last resort, only to be=20
>=20
> used =20
>=20
>>>>>>when speed is top priority and not accuracy.=20
>>>>>>Although some of the FHT problems could be solved with=20
>=20
> calibration I =20
>=20
>>>>>>still don't think you will get as good results as when you=20
>=20
> correlate =20
>=20
>>>>>>in the frequency domain. I'm not sure that the FHT errors are=20
>=20
> static =20
>=20
>>>>>>enough to be effectivly removed with calibration.=20
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>I must get started on a test/demo app.=20
>>>>>>
>>>>>>
>>>>>>
>>>>>>I have almost finished a waveform viewer/library that can be=20
>=20
> used =20
>=20
>>>>>>from other appplications, so you might want to wait for that.=20
>>>>>>I will make it public as soon as I figure out where to put it.=20
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>>One final thing. If we have upgraded the project name to level=20
>=20
> 1 =20
>=20
>>>>>>>then I think we need to upgrade the major revision number to 1=20
>=20
> as =20
>=20
>>>>>>>well. Perhaps 1.0.=20
>>>>>>
>>>>>>
>>>>>>
>>>>>>I agree on this, although I don't think we should go 1.0 until=20
>=20
> the =20
>=20
>>>>>>library is stable.=20
>>>>>>
>>>>>>/Daniel=20
>>>>>>
>>>>>>
>>>>>>
>>>>>>
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>>>>>>
>>>>>
>>>>>
>>>>>
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