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ux226 3rd August 2006 10:15 AM

Speaker measurement, FRD and ZMA

I have this reasonably decent measurement setup:

ESI Juli@ sound card (24bit/192KHz full duplex)
Behringer ECM8000 Mic
Behringer UB802 Mixer/Preamp
TrueRTA 1/24th octave software
audioTester software

and that all works pretty good.

What I need to do at this moment is to measure some speaker units in their actual enclosures and produce FRD and ZMA files that I will then use to simulate x-overs. I need the files to contain both amplitude(dB or ohms) and phase.

How do I get around that? I'm am all open for yet another piece of software if need be. I just hope it won't cost me too much ;)

FullThrottleRic 3rd August 2006 01:54 PM

Speaker Workshop will let you create FRD and ZMA files from measurements, it will also do the simulations for you and best of all it's free :cool:

ux226 3rd August 2006 03:22 PM

Thanks a lot.
I just downloaded it and installed it on my laptop... Exploring the software should keep me occupied in the train on my way home from work today ;-)

Calvin 3rd August 2006 04:09 PM


depending on the software You can ´fudge and cheat´ a bit.
The .frd and .zma files are just a text files with the first column containing the amplitude values and the second column containing the phase values. A lot of software outputs its data the same or a similar way.
Just open the data files with the editor and have a look! If there is a headline..just delete it. Save the files then as standard text-file with the proper ending.

DLSA generates .amp and .imp files that look like this:

for a file "drivername.imp"

"Freq[Hz] Imp[Ohm] Phas[Deg]"
12.5 3.1 5.3
25.0 3.1 5.2
37.5 3.1 5.7
and so on

the "drivername.zma" file would look like this:

12.5 3.1 5.3
25.0 3.1 5.2
37.5 3.1 5.7
and so on

So apart from the missing headline and the different file ending they are the same!


hongrn 3rd August 2006 04:19 PM

Hello ux226,

Instead of Audio Tester and TrueRTA, use Arta. Arta measures frequency response, phase, impedance, and will allow you to export to zma and frd. Good luck.


Calvin 3rd August 2006 04:43 PM


uuups a correction:

The format is three columns not just two :whazzat:

First: Frequency
Second: Amplitude value
Third: Phase value


ux226 3rd August 2006 06:48 PM

I spent the time in the train home from work reading the entire Help file of Audua Speaker Workshop. It seems to be able to do all I need.

I have downloaded and looked at the program several times before, but every time I found it to be so non-intuitive to use that I dumped it again. After reading the Help file from start to finish and navigating the interface a bit I believe I'll get the hang of it. It seems like a very powerful package once you get familiar with it.

I think Speaker Workshop will be one of my primary development tools from now on. TrueRTA is however so good at measurements of complete systems from the listening spot that I will never regret that purchase.

I had a brief look at Arta just now, and I think I'll see how far Speaker Workshop gets me before spending time (and eventually money) on that. Thanks a lot for the pointer though - that's one program I had never seen before.

Now, please have me excused - I have a bunch of experiements to do! :D

JMB 3rd August 2006 11:12 PM

If you are interested in a really good tutorial, go to Claudio Negro's home page at If you then want to delve further, I have put together a fairly comprehensive manual that you could download there. In addition to SW information, it has a slew of spreadsheets and general audio information that may be of interest to you. It is a large file, however.

Good Luck,


ux226 4th August 2006 07:27 AM

Wow. I'm impressed! :bigeyes:

I just read the TOC and first 4-5 pages of your manual Jay, and I look forward to reading the rest of it. Great work!

For once I'm actually happy that I travel 1h30m each way :dodgy: for work by train... Gives me the time to read stuff like this. ;)


JMB 4th August 2006 12:52 PM

Thanks. I hope that you have time to evaluate the spreadsheets and helper programs, as well. I believe that they are quite helpful and educational. I have put together a few others since the second edition. I am currently in the process of compiling all of the notes I have taken and several new spreadsheets into this Manual. I don't know that I will post it as the size is getting to be quite large, however, I will be watching for questions on the boards and will share what I have gathered or put together as appropriate. I am not an expert but a very obsessive learner.


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