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Some expert advice needed from you on FRM. How are you doing it? Techniques?

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  • Some expert advice needed from you on FRM. How are you doing it? Techniques?

    So as I understand it. The best way to do a FR with out an anechoic chamber in a room is this. 1st. Measure the tweeter at a distance of around 1cm. Then do the same for the woofer. Now with both measurement import FRD in PCD program, and it will merge the two? Will this work for HT XOVER program as well?

    Or what are you guys doing? Just measuring from say 1 meter away, and somewhat ignore the low frequencies? I just doing it by ear? I've heard going out side can work, weather can be an issue there. Especially if you live where you have cold or rainy season?

    On the cheap diy. That is my motto - www.hifiposse.com

  • #2
    I think you must have skipped the "Stickies" at the top of the Forum. There must be at least 2 writeups on using "ARTA" (which can be free) w/a calibrated mic. You can measure at 1 meter (39.4", 39" would be good enough - some cut that distance in half, if you'll be listening to them "up close" - like on a desktop), but you (ideally) want them about 4ft off the floor (in a room w/8ft ceilings) and 4ft from walls. Then you measure using a "windowed impulse", typically with a gating time near 3.33ms, which I think is accurate down to about 300Hz. For a 2-way (and the ever-popular "PCD" - by Jeff Bagby, or one of several "workalike" softwares -which are all FREE - thanks to the talented nice guys here on PETT), you need to start w/2 .frd files (response), and 2 .zma (impedance) files. They don't really get "merged". You'd use them to model a high-pass filter, and an LP filter (for the woofer), then the software sums the 2 drivers (providing you can measure or generate appropriate phase date) to show you the modeled system response.

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    • #3
      Thanks, I have an omni mic setup. The gating is set to 5.0 ms. I'll see if it lets me play with the time. I've been looking for decent videos on youtube, but have to found any. I am in a smaller room, and this makes me thing I need to consider moving to a larger room. Yes I skipped the stickes. I should have look at that first. Forum newbie mistake.
      On the cheap diy. That is my motto - www.hifiposse.com

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