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RE: "I thought you had to reverse the polarity even on the 1st order slopes"??? ...

For a symmetrical 1st order crossover (same fc), polarity is irrelevant except perhaps to those freaks who can hear absolute polarity. Let's assume the phase at frequency x for the LP is 0 deg., then the phase for the HP is 90 deg. and the difference is 90 deg. Inverting the polarity on the HP makes it -90 deg. and the difference is still 90 - same difference. Now for asymmetric 1st order xo's the phase difference are not the same (not 90 deg) at all frequencies so inverting will result in a different phase difference. If the fc are far apart, then one may get the drops in the output and inverting may correct this.
As an example here is a bode diagram for the MG-IIb. The fc's of the LP and HP are 2 octaves apart and you can see the drop out for the same polarity that flattens with the inversion.


And here is a Bode diagram for a symmetric 1st order XO that crosses at the same frequency. Note the output only shows as a white line (the magenta line coincides and is obscured). The output is dead flat and if you look at the phase plots they are are always 90 deg apart.




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  • RE: "I thought you had to reverse the polarity even on the 1st order slopes"??? ... - neolith 06:01:55 03/22/12 (0)

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