Support Forums Forums FIR Creator Support Binary File 32bit Float wrong result on MiniDSP 2x4HD

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  • 16 February 2022 at 7:42 am #410

    Hello, today I have installed the FIR Creator to make an Phase Correction of my passive 2 way Bookshelf speaker with passive crossover, which is set up close to the back wall. I use one channel from my MiniDSP 2×4 HD for the right speaker and one other for the left speaker. Two outputs are free from MiniDSP.

    I have taken several measurements in REW, than time aligned and averaged the whole.
    Here is the link to the measurements.

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    There we can see early reflections from the back wall and from the floor. So there is a dip and some Phase Wraps between 200 and 300Hz.
    I want to correct the Phase and the Amplitude over 400Hz. I want to correct the Amplitude below 100 Hz.

    Afterthem I exported the Averaged measurement for each channel as a text file and import it into FIR Creator.In this example I take the Left Channel.
    Here is a screen shot of the import Window in FIRCreator. I have flipped polarity to get phase regions close to 0 Degree.

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    i proceed with the following steps as in the tutorials described and ended up at the Export Tab. I correct filter delay and length, so that the total error is close to zero from 500hz – 20 000Hz. and the phase is flat from 500hz – 20 000Hz. (2048taps maximum in 2x4HD) Here is the link to the export tab.There you can see clearly which Filters are set.

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    Here is the link to the export tab with an other view. There you can see clearly which Amplitude I expect.

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    I export the bin.file to my MiniDSP 2x4HD in the FIR Menue. Here is the link:

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    Here you can clearly see, that the amplitude correction file is not the same, than I see in the export tab of FIR Creator. Where is the problem? I tested all, but I can´f find a solution.

    Afterhem I started a single measurement of left speaker at the reference point in REW with activated FIR filter and a second measurement without FIR Filter.
    Here is the phase with an FDW of 6 cycles.

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    Here is the frequency response with an FDW of 6 cycles

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    In Both Windows we can see, that something has changed. But the solution is not what I calculated and expect in FIR Creator. I think the problem is, that MiniDSP false interpret the filter coefficient from FIR Creator.

    Can somebody help me by finding my error of thought? I am meanwhile dispaired. Hope the links work.

    Here is the link to the fdp. File of FIR Creator

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    Here is the link to both final measurements with activated and deactivated FIR Filter

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    What I have tested to solve the problem:
    I have tested it with an other MiniDSP2x4HD. But it is the same Problem.
    Procedure with Mac Bookpro with Intel Processor
    Procedure with Windows PC
    I have tested FIR Coefficient until 2048 taps. (MiniDSP 2x4HD don’t support anymore)
    Nothing helps.

    I Use mainly 14“ Mac book pro 2021 monetary M1Pro
    REW Version 5.20.4
    MINI DSP2x4HD 1.17 firmware 1.14

    Thank you already once for your help.

    Kind regards
    David

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