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-   -   FRD/ZMA Problem (http://www.diyaudio.com/forums/multi-way/91531-frd-zma-problem.html)

Twisted85 3rd December 2006 07:06 PM

FRD/ZMA Problem
 
Hi,

I just introduced myself to frd and zma files, because I'm planning to make my own simple 2-way speaker.

I downloaded "Passice crossover designer 5.10" which seems like a easy to use program. I tried to Load the sample FRD files to the program and it works perfectly.

Then I downloaded SPL Tracer program, and tried to make my own FRD files. I made all the required alignments and made the file by selecting the correct points.
The probles is, that when I load this file to the crossover designer, it doesn't work correctly.

This what the response looks like :
http://personal.fimnet.fi/private/clan/response.jpg

These are the first three lines of the FRD I made with SPL Tracer:

20 77,91209 0
20,63071 78,24176 0
21,28132 78,50549 0

And these lines are from a working sample file:

10 29.4903 -28.5158
10.1517 29.499 -28.4475
10.3056 30.0283 -28.0261

I tried to do another frd file with another speaker response with no better results.

Am I doing something wrong or isn't SPL Tracer and the passive crossover designer just not compatible?

claudio 3rd December 2006 07:34 PM

The format is the classic Frequency - Amplitude - Phase.
The problem is that your file uses , for decimal, while the sample file uses . as for decimal: change your file "," with "." and you should be set.

Twisted85 3rd December 2006 08:46 PM

Thanks for your reply.

There is 400 tracepoints and if I have to change both frequency and amplitude decimal symbols to a ".", which makes 800 corrections.

Is there a way to do this with somekind of text editor?

Or is there a alternative for the SPL Tracer?

(In the FRD the SPL Tracer generates the Phase is set to 0 at every frequency, is this a problem?)

claudio 3rd December 2006 08:56 PM

It's very easy to do:
open the file with Win NOTEPAD, then MODIFY/SUBSTITUTE and write "," in FIND and "." in SUBSTITUTE WITH; the click on "substitute all" and the job is done.

The phase always at 0 will mean you are not considering the phase, so it's not useful for crossover design.

Twisted85 3rd December 2006 10:02 PM

Quote:

Originally posted by claudio
It's very easy to do:
open the file with Win NOTEPAD, then MODIFY/SUBSTITUTE and write "," in FIND and "." in SUBSTITUTE WITH; the click on "substitute all" and the job is done.
Well that was almost too easy, but I wasn't aware of that function :D Thank you.

Quote:

The phase always at 0 will mean you are not considering the phase, so it's not useful for crossover design.
I believe I should read this through and I try to understand something :cannotbe:

claudio 4th December 2006 01:19 PM

Quote:

Originally posted by Twisted85

I believe I should read this through and I try to understand something :cannotbe:

In RBJ example, the result is within 2 dB from the measured response: even if the 2 dB difference can't be taken as a general rule, it's a big value, in my opinion.
The FR Combiner allows you to calculate the minimum phase starting from the frequency response: in my Home Page I show this procedure as well, starting from a measured response.


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