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  1. #1

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    Default SDA Crossover frequencies, are they 2000Hz as published? calculations shows 1000Hz

    Most SDA crossover frequencies as published are 2000Hz. Did some some calculations with tools from www and Vance Dickason's book, and the results with second order 12dB filters are 1000Hz.

    Or is there a Polk trick I am unknown off?

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    Are you calculating based on "all" the circuitry/components involved?

    The SDA crossover schematics are hugely more complex than what is shown, for example, in the ERSE web site crossover calculator, where a second-order high-pass crossover is one capacitor and one inductor, while a second-order low pass is one inductor and one capacitor.

    http://www.erseaudio.com/Second-Order-2-Way

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    Hallo Schurkey,
    I meant the crossover filter frequency of the Stereo driver. Thats a second-order low-pass filter.
    It has the same crossover filter frequency for the high pass. (to prevent a hole or bump, you know)

    The SDA inductor of 16 mH is for the Sub-Low, that is an other sory.
    Tomorrow I will try your ERSE calculator, but not expect difference with other online calculators.
    Now I go asleep, its midnight here in the Netherlands.

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    Using online crossover calculators are like peeing in the dark. They don't take into consideration that a driver's impedance curve is rarely ever flat, making them inaccurate almost every time.

    To get an accurate reading of a driver or speaker impedance, you need a much more complex tool such as a DATS.
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

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    Hallo Face,
    I never realised calculator results are so far off the published 2000 Hz cross over requency.
    This morning with another online calculator shows cross over of less than 1000 Hz, remarkable.

    A soundcard measuring tool will show what is correct or wrong.

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    WHICH speaker model are you calculating for?

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    The CRS+ first, but other models gave the same result, at or below 1000 Hz

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    Quote Originally Posted by freak1942 View Post
    Hallo Face,
    I never realised calculator results are so far off the published 2000 Hz cross over requency.
    This morning with another online calculator shows cross over of less than 1000 Hz, remarkable.

    A soundcard measuring tool will show what is correct or wrong.
    What card, how will you be measuring?
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

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    It seems no one can explain the big difference from the published xover frequency of 2000Hz and the calculated 1000Hz.
    Planning to make a replica of the CRS+ as close as possible, and take the result as is, no soundcard and/or software tools so far.
    Ordering drivers from Polkaudio, and new filter circuit boards from Vr3mod are on my list.
    Will also use the Dreadnought AI interconnect Avel 1000VA transformer which is still lurking on the loft.

  10. #10

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    I explained it, you just can't comprehend it.

    This should help: http://techtalk.parts-express.com/sh...Building-Bible
    "He who fights with monsters should look to it that he himself does not become a monster. And when you gaze long into an abyss the abyss also gazes into you." Friedrich Nietzsche

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    Planning to make a replica of the CRS+ as close as possible
    It would be cheaper to buy a pair here and have them shipped to you than it will be to build a pair.
    'Political Correctness'.........defined

    "A doctrine fostered by a delusional, illogical minority and rabidly promoted by an unscrupulous mainstream media, which holds forth the proposition that it is entirely possible to pick up a turd by the clean end."

  12. #12

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    To Face,
    Understanding your message, thanks for PE url, great.

    To F1nut,
    Today found on Epay a CRS, ships to US only, sent seller a msg.
    Expect shipping cost as much as BuyNow price.

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