Klippel Near Field Scanner on a Shoestring

What's keeping us from trying something?
True, we do have a lot of know how at our hands, but we all have a life, and we all have to make choices about which projects to pursue in our free / hobby time.

Someone will have to commit to actually design and build a contraption that moves a microphone on different spheres around a speaker.
Someone will have to commit to develop the software to control the thing, and interface the software with a measurement tool (be it ARTA, MATAA, whatever).
Someone will have to keep all the pieces together.

I would be in to support this by helping with MATAA stuff, if I can see that the whole thing is going to be documented and maintained publicly in an open-source way, with all the nitty-gritty needed for others to just copy the system for their own needs. A GitHub repository might be nice.
 
I am not the right person to ask this, because I will say that MATAA can do everything :) (and that's not a lie!)
Also, I am not very familiar with REW, but I guess it does not give you access to the raw data and scripting in the same way as MATAA does. Once you'd want to integrate the different parts into a complete system, it may be handy to use a software that comes with a license that actually allows this. The REW discription says it's "free", but I can't tell if it's free as in free beer or free as in free speech. MATAA comes with the GPL license, which allows you to use it for whatever you want.
 
@mbrennwa : do we need REW, or should MATAA be enough? Any thoughts?
REW is Programmed by John Mulcahy. He has presented a much more Pro version of REW that does turnatable call outs. I think that it is mentioned in that thread posted above. I am know nothing of it following the same conventions as ARTA.

So I have a question. Does MATAA create files that are readable by other programs like ZMA and FRD files? Most loudspeaker programs seem to be following that system of file creation.

I am guessing that all this may be in the MATAA manual. I should look there for myself.

Mark
 
If I remember correctly, those are just human readable files. I'm not at a computer, so I can't check it, but this info also indicates that:

"The format is compatible with the .FRD format. Comment lines start with *, data lines begin with the frequency, then the SPL in dB and finally the phase in degrees (0.0 if the measurement does not have phase information)."

MATAA is 'just' a set of Matlab/Octave functions. You can make Matlab/Octave do anything you want; you just have to write the code.
 
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Yup, it has some functions for that. Why would that be relevant for the Shoestrings project?
For data manipulation after acquisition. I'm trying to think ahead here. System design, not part design. The mechanics of this measurement system are not to big a deal for me. I have a background in a few trades. The getting automation I am not so strong in, or the software. I am basically tying to line up all the pieces in order to have a global concept of what needs to be done.

Mark
 
Data manipulations is a core strength of Matlab. I'd rather do the manipulation in Matlab than in REW, unless it is extremely advanced math that REW already implemented.

Matlab and Octave are similar. MATAA runs in both.
Exactly. The idea would be to keep everything in Octave (or Matlab) for the Shoestring automation, acoustic measurements, and data processing.
I personally don't recommend using Matlab, because it's super expensive and messy with licensing. Last time I looked, Matlab did not run on my preferred operating system. GNU Octave solves all these issues.

I'm an Octave newbee. Still haven't figured out how to load MATAA :rolleyes:
Just learn the basics of how to install, configure and use Octave and you'll understand how to use MATAA. You don't "load" MATAA. I recommend reading the manual and the AudioExpress article. Then ask questions in the MATAA channels, for example in the MATAA thread here on diyAudio. Let's not pollute the Shoestrings thread with basic MATAA questions.
 
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The mechanics of this measurement system are not to big a deal for me. I have a background in a few trades.
I've been looking on the internet for stepper motors. I've not much experience with them, but the arta_tic experience gives me some confidence that I should be able to get them moving :)
Do you have a sketch of how you envision the mechanics? I hope to get a feeling for the kind of motion (translation vs rotation) and the forces (moments) needed. I'm also looking at open and closed loop steppers.
If anyone has ideas or experience, please share it.

And what measurement method are we starting with? The full klipper way or the averaging way?
 
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