Need help with .zma files in FRC

[diesel_88]

I'm a little unsure how to use .zma files with the FRD consortium tool set--can someone help?

Using FRC, there is a function to auto-extract the impedance phase. It asks for an input file, then writes the phase data to the output file. What do I use for the input? At that point in the simulation, the only .zma file I have is the mfr.'s impedance trace. Is that the right one to use?

Reason I'm confused: what about the effect of the enclosure on the impedance of the circuit? Unibox lets you output a .zma file, but FRC does not merge it with the original mfr's file. Does FRC's auto-extract function account for enclosure effects?

Thanks much,

Cam

[omni]

Diesel......The website rjbaudio.com has a tutorial on using the FRC tools......Roman Bodnarek put together this tutorial, and I would simply study it and follow its' instructions as you go along ...It is written in a chronilogical order, and as you follow it, everything should fall into place....Omni

[diesel_88]

That's a very good tutorial; it's gotten me this far. About impedance phase it says, "Next, select the impedance file you want to process." The FRC manual says, "When you click on the 'Impedance Phase Auto-Extract' button, the user is prompted for a ZMA filename to load."

Neither one says exactly which ZMA file to use. Is the manufacturer's raw impedance curve the right one? If so, what about effects from measurement conditions and enclosures...does FRC account for them automatically? Are those effects negligible? Or am I missing something (which is usually the case)?

Just trying to make sure I don't feed garbage into the crossover design.

Thanks!

Cam

[omni]

You use the impedance files for each driver that was processed through the other tools that are loaded into the Frequency Combiner, ie after you load all the resultant files you created for, say, the tweeter, you extract phase information for that driver.....Then you move on to the midrange, then you move on and process the woofer......It is a little confusing, and I found myself sitting in front of the computer, tutorial in hand, going back and forth, trying to decipher it as I went along......It just takes a little time, and in a few instances I scraaped it all , and started from scratch......I founf that the more I worked with it, the clearer things became.....

[croat47]

I can not seem to create or use downloaded ZMA files. That is:

1) Downloaded ZMA's (for sim purposes only) turn into TXT files.

2) Even taking a ZMA from the Passive Corssover Sheets and saving it elsewhere turns it into a TXT file.

3) When I try to open a TXT file with ".ZMA" extension in the sheets, it only lets me select Impedance File Types, not "all" file types for options. So, the .ZMA extension text files do not show up.

I have no issues with FRD files. What am I missing?

Thanks!

[diesel_88]

Try saving your files as "xxx.zma" with the quotation marks in the "File Name" field. This will work if you're using Notepad on a PC as your text editor. I think you can do the same thing with Excel.

[diesel_88]

...for an Excel file, you have to set the file type for space- or tab-delimited.

[diesel_88]

Originally posted by omni
You use the impedance files for each driver that was processed through the other tools that are loaded into the Frequency Combiner, ie after you load all the resultant files you created for, say, the tweeter, you extract phase information for that driver.....Then you move on to the midrange, then you move on and process the woofer......It is a little confusing, and I found myself sitting in front of the computer, tutorial in hand, going back and forth, trying to decipher it as I went along......It just takes a little time, and in a few instances I scraaped it all , and started from scratch......I founf that the more I worked with it, the clearer things became.....

I think I have a handle on the process up to the point of extracting impedance phase--that's where I start to scratch my head. Once I've saved a combined FRD plot, click "Impedance Phase Auto-Extract," and FRC asks for an input file.

At that point in my design, the only ZMA file I have is the trace of the manufacturer's impedance plot. If I input that file, then there's no accounting for the effect of the enclosure on the impedance plot. Maybe my understanding is wrong, but I thought enclosure resonances affected the impedance curves of a speaker.

What am I missing?

[omni]

Did you run your original TRACE files through the unibox and baffle diffraction programs before attempting to use the Frequency Combiner program?

[diesel_88]

Here's the procedure as I understand it--maybe you can point out where I'm going wrong. (Dummy file names used for clarity)

1. Trace mfr.'s plots: MFR.FRD and MFR.ZMA
2. Generate infinite baffle response (if that's how the manufacturer tested): IB.FRD.
3. Generate target enclosure response: BOXTARGET.FRD
4. Generate target baffle response in Baffle Diffraction Simulator: BAFFLETARGET.FRD
5. Load MFR.FRD, IB.FRD, BOXTARGET.FRD, and BAFFLETARGET.FRD into FRC and normalize per instructions (using 2PI for the baffle measurement assuming infinite baffle. I don't use Room Response). Generate a combined response curve.
6. Select "Precise Phase and Group Delay," and extract minimum phase data from the combined response curve. Save combined response curve: COMBINED.FRD
7. Select "Impedance Phase Auto-Extract." FRC asks for an input file; point to MFR.ZMA. When finished, save new plot as COMBINED.ZMA

I then use COMBINED.FRD and COMBINED.ZMA in Passive Crossover Designer. It seems like I'm doing something wrong on step 7, because I don't account for enclosure effects in the impedance plots, but I'm not sure what the right way is.

Thanks for your help!