# .frd and .zma files
**URL:** https://discourse.midwestaudio.club/t/frd-and-zma-files/262
**Category:** Hard Data
**Tags:** 3-way
**Created:** [November 2, 2025, 8:16pm UTC](https://discourse.midwestaudio.club/t/frd-and-zma-files/262 "2025-11-02T20:16:48Z")
**Posts on this page:** 3
**Page:** 1
### Author:  [@danny](https://discourse.midwestaudio.club/u/danny)
#### Post date: [November 2, 2025, 8:16pm UTC](https://discourse.midwestaudio.club/t/frd-and-zma-files/262/1 "2025-11-02T20:16:48Z")
I have a couple of 1950’s era Klipsch Shorthorns. I want to build new 3-way crossovers using online crossover design software. The first thing they all want is .FRD and .ZMA files. I don’t know how to get them for these old drivers. Let’s start with a Stephens Trusonic 103LX woofer. I have done a lot of fruitless site exploration. Does anyone care to offer suggestions. I will reply to all.
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### Author:  [@Ani](https://discourse.midwestaudio.club/u/Ani)
#### Post date: [November 2, 2025, 10:35pm UTC](https://discourse.midwestaudio.club/t/frd-and-zma-files/262/2 "2025-11-02T22:35:46Z")
You will need a measurement microphone and free software like REW to measure FRD. You will need something like DATS to measure impedance ZMA.
Online calcs are next to useless, you’ll need to learn or ask someone to help design proper XO.
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### Author:  [@DrewsBrews](https://discourse.midwestaudio.club/u/DrewsBrews)
#### Post date: [November 2, 2025, 11:24pm UTC](https://discourse.midwestaudio.club/t/frd-and-zma-files/262/3 "2025-11-02T23:24:02Z")
(Pulled from the other thread he started)
> [@What is my new username?](https://discourse.midwestaudio.club/t/what-is-my-new-username/261/4):
>
> Thanks, Drew
>
> I am in New Braunfels, Tx., between San Antonio and Austin. Do you care to tell me how to take the measurements and save them in the correct file format? Do I need to buy an expensive microphone? Can the measurements be made by instrument? Maybe the “Geek Squad”?
The .frd is the frequency response measured with a calibrated microphone connected to computer. Just using any mic is dubious as there is no way to know how inaccurate it is.
(I use the Dayton audio UMM, which the current version UMM6 is $95. Other folks will problably say using x or y in z config is better. This works for me, ymmv )
The .zma is the impedance measurement across the frequency range. A “DATS” or “WT” (woofer tester) can be used. But a “LIMP” box can be made with a few cables and resistor. Though the LIMP box requires appropriate audio outputs and inputs (audio out and line in type that are able to send and receive at the same time) on your computer and configuring software to work. The DATS and WT incorporate those outputs and inputs within the unit and have dedicated software that is a bit more streamlined for that more specific use, but you pay extra for the convenience. (I made a LIMP box to use for a while, but eventually splurged for a DATS V3 which is currently $130)
The above stuff is more specialized for speaker builders or folks in the audio industry. I am not familiar with Geek Squad’s capabilities, but I would be surprised if they do.
Have you checked out the Klipsch Audio Community? ([https://community.klipsch.com/](https://community.klipsch.com/))
I’m not a member of that forum, but I have done some lurking. Rather than completely redoing a crossover with a new design. They seem to focus more on working with the original designs.. IE: updating to new parts with same values or making tweaks.