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Crossover point for a tweeter

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  • Crossover point for a tweeter

    This tweeter https://www.parts-express.com/peerle...eter--264-1016 has an Fs of 436. What I have heard is that typical logic depending on the crossover steps, etc, that you could cross it over at 1090 Hz or say 1300 Hz. Can tweeters really be counted upon to produce the rest in a two way design. Should it really be crossed higher even though the Fs is so low?

  • #2
    A few tweeters follow that ROT but a lot don't. The XT25TG needs to be crossed much higher. The harmonic distortion performance of the tweeter determines the minimum crossover point much more so that the Fs.
    Craig

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    • #3
      Originally posted by PWR RYD View Post
      A few tweeters follow that ROT but a lot don't. The XT25TG needs to be crossed much higher. The harmonic distortion performance of the tweeter determines the minimum crossover point much more so that the Fs.
      Needing to learn what to look at, how would you go about determining harmonic distortion? Would that require personal measurements? would you look at the graphs specs provided by Parts Express?

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      • #4
        Max SPL required, excursion HD profile and acoustic order determine how low moreso than the resonant frequency. Maybe the Fs of the tweeter does correlate. Usually most passive crossovers target a much higher than Fs xo point such that resonant peak compensation isn't required to tame the tweeter Fs to achieve the target HP transfer function and acoustic rolloff.

        For a conventional 1" or thereabouts dome tweeter - waveguide loading will help "boost" low frequencies and therefore allow lower acoustic XO due to the boost for a given electrical transfer function (i.e. allows a tweeter to play lower with the same electrical transfer).

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        • #5
          Originally posted by audiohob62 View Post

          Needing to learn what to look at, how would you go about determining harmonic distortion? Would that require personal measurements? would you look at the graphs specs provided by Parts Express?


          In this case for HD you would need to either rely on a third party measurement (like Zaphaudio) or measure it yourself. The manufacturer graph provided by PE only shows frequency response and impedance.
          Craig

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          • #6
            Originally posted by PWR RYD View Post
            In this case for HD you would need to either rely on a third party measurement (like Zaphaudio) or measure it yourself. The manufacturer graph provided by PE only shows frequency response and impedance.
            I'm still trying to figure out simple FRD using a measurement mic and ZMA with DATS.
            What do people use for Harmonic Distortion measurements and Polar Response graphs? Is it the same mics and standard software (REW, Holm Impulse, ARTA, etc.)?

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            • #7
              Thank you so far. I have a lot to learn.

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              • #8
                Originally posted by a4eaudio View Post

                I'm still trying to figure out simple FRD using a measurement mic and ZMA with DATS.
                What do people use for Harmonic Distortion measurements and Polar Response graphs? Is it the same mics and standard software (REW, Holm Impulse, ARTA, etc.)?
                Yes same mics and Holm, Arta, Soundeasy, or OmniMic.
                Craig

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                • #9
                  I just finished a project using that exact tweeter and it definitely needs to be crossed over above 2kHz. Try about 2500Hz. For the money, that Peerless tweeter is really very good.

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                  • #10
                    Looking at the FRD you'd say it would work to 1kHz, maybe a bit lower, at least in terms of response.
                    Distortion happens when you get up around xmax. The 0.5mm xmax of this tweeter is very generous, indicating that it might work just fine to 1kHz, though I wouldn't do so with only second order high passing, otherwise excursion below 1kHz could limit it to low power before THD became severe. The only way to know for sure would be to measure THD at various power levels and filter slopes.
                    www.billfitzmaurice.com
                    www.billfitzmaurice.info/forum

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                    • #11
                      I suspect the DX25 is a bit easier to work with. I have one of the double magnet ones, very nice unit.

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                      • #12
                        Originally posted by audiohob62 View Post
                        This tweeter has an Fs of 436. What I have heard is that typical logic depending on the crossover steps, etc, that you could cross it over at 1090 Hz or say 1300 Hz. Can tweeters really be counted upon to produce the rest in a two way design. Should it really be crossed higher even though the Fs is so low?
                        I wouldn't cross any tweeter lower than 2.5kHz. This one needs to be crossed higher than 3kHz.
                        It was my first design with this tweeter.
                        Some measurements:
                        https://hificompass.com/en/speakers/...fa-xt25tg30-04

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                        • #13
                          As long as you comp the Fs, the XT25TG30 is okay with a xover at 2.2k. I know who you are supposed to be George, but a blanket 2.5k statement xover point like that really isn't the best answer. There are quite a few tweeters out there that can do 1.8k easily now.

                          Later,
                          Wolf
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