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how to generate fdr and zma files  

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Toad
 Toad
(@toad)
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18/02/2020 8:16 am  

hey guys im noob at speaker design and im trying to get my own fdr and zma files. i have my drivers in the enclosure and have umik-1 mic and rew down loaded. i cant seem to find any info on how to get the files. im not sure if im just typing in the wrong thing or what. if anyone knows any good links of step by step how to set everything up that would be great. or even a link to a video. i prefer videos.


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DIYAudiphileElliottBridge
(@diyaudiphileelliottbridge)
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18/02/2020 3:47 pm  

Hello, sorry for the late reply. I haven't been on at all today.

Awesome, you are doing these tests 1m away and on an open field or similar area (that is how you get the best results other than using an anechoic chamber LOL). You can still use your room but your speakers will not be room independent and you will have masses of dips and peaks in the response due to room modes. However, you asked how to record them into ZMA and FRD files so I will tell!

Firstly have you downloaded RoomEQ Wizard as this is by far the cheapest method (for what I know anyway)? If you do a sweep with this it will give you the frequency response, you can then use a program named FP graph tracer which will convert an image of the response (taken with screenshot/snipping tool) into usable data files.

Now there is another way but it is quite expensive: the Dayton Omnimic computer package (have a google you should find it straight away). It will do it all in one go.

Now there are another 2 options for the ZMA files either. 1. Use the nominal impedance of your speaker usually 2, 4, 8, or 16 ohms. 2. Use a speaker tester like the Dayton DATS V3 system which is expensive but at least you have an accurate representation of all your speaker's characteristics (apart from FR) which can be very useful.

Pick your options and get back to me if you need any help understanding anything or need anything clarified. 😀

P.s. Sorry, I don't know of any videos, I prefer them too!


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ImCoKeMaN
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18/02/2020 5:45 pm  

@123Toid looks like this is a good idea for your next video!!

Disclaimer: I've been in the forum long enough to know a couple things, but have yet to actually do a speaker build myself =)


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Toad
 Toad
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19/02/2020 7:44 am  

i already have room eq wizard down loaded and ill be doing the measurments indoors since there is a lot of snow and way to cold outside. the questions i have are how do i set things up in room eq wizard  for doing the sweep and how far should i have the mic from the speaker? 


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DIYAudiphileElliottBridge
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19/02/2020 10:18 am  

@toad

Try and set your speaker up in the centre of the room, maybe set back a little and have the mic 1m away from the speaker at the height of the tweeter, pointed directly at it. As for taking the measurements, there should be a measurement button... Here is a video that should explain the measuring part of it better than me explaining it (it is a bit old but still applies):

Once finished, I can walk you through the graph tracer if you want. 🙂

 


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123Toid
(@123toid)
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19/02/2020 3:17 pm  
Posted by: @toad

hey guys im noob at speaker design and im trying to get my own fdr and zma files. i have my drivers in the enclosure and have umik-1 mic and rew down loaded. i cant seem to find any info on how to get the files. im not sure if im just typing in the wrong thing or what. if anyone knows any good links of step by step how to set everything up that would be great. or even a link to a video. i prefer videos.

Toad,

Go ahead and take a measurement like normal.  If you are in room, have your microphone about 16" away centered on the tweeter. Keep this height when measuring both drivers.  Once you do a sweep, go to file export as text.  There name your file and add .frd to the end.  This will give you your frd file.  Rew doesn't give you the zma file for that, you need Dats or something similar. Here are two videos that could really help you out as you get started.


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Toad
 Toad
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20/02/2020 8:29 am  

awesome thanks for the help. ill try it out this weekend


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TVOR-Ceasar
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20/02/2020 2:20 pm  

There is a link in another post that shows you how to create ZMA and T/S parameters for very little outlay. Look for DIY method by @richardbmw near the bottom.

-Charlie


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Toad
 Toad
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23/02/2020 4:25 pm  
woofer fdr
tweeter fdr

 i took some measurements in room. my measurements are kinda similar to the factory. the purple line is my measurement of the woofer and i got a dip around 500hz. im assuming this is a null in the room? will this effect my crossover design? for the tweeter my measurement is the purple line again. for both of my measurements the db level is lower than the factory measurements. is that because i didn't have my amp turned up loud enough? i just used the factory zma files cuz i dont have a dats 3


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123Toid
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23/02/2020 4:57 pm  

The 500 hertz is probably just a null in your room. This is a common occurrence seen between 200hz and 300hz in most rooms. To know for sure, you can take a nearfield measurement of the woofer itself. Just put the mic real close to the woofer, almost touching. That will get rid of any room reflections. Either way it won't be integrated in your crossover design.  I'm assuming you're taking a measurement around 16 in? If so, that means everything really below 500 hz is not accurate. 

The fact that it's not lining up just means that your amp wasn't at the same voltage as there's when they measured it. That's not really an issue, unless you want to know what the sensitivity of it is. But most of us that's a moot point. if you're going to commercialize it, you would need to know it that.


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Toad
 Toad
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23/02/2020 6:09 pm  

yeah i was 16" away. ill try again with it up close. thanks again with the help

 


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Toad
 Toad
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23/02/2020 6:10 pm  

now if i was to do it outside would i still want the mic to be 16" away?


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