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Is my Phase too fat?

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  • Is my Phase too fat?

    Been working on my first (well technically second) design. MTM with Eclipse and Satori TW29. I use REW for measurements and primarily WinPCD for the XO work. Since most folks here use PCD I imported into that for the screenshots. I like what I have so far but not sure how this phase looks. Bad? good? Weird? I use the min phase generated in REW.

    Click image for larger version

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  • #2
    While not "perfect" tracking (for LR2/4), it certainly isn't bad between 200Hz and about 4k (before diverging).

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    • #3
      That isn't too shabby. Try adjusting the tweeter values just a bit and they will come right into line.

      What is the lcr for on the woofers?
      https://www.facebook.com/Mosaic-Audi...7373763888294/

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      • #4
        Originally posted by isaeagle4031 View Post

        What is the lcr for on the woofers?
        For the peak as discussed in that previous thread.
        Click image for larger version

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        • #5
          The small cap did not knock that out?
          https://www.facebook.com/Mosaic-Audi...7373763888294/

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          • #6
            Make sure you have entered in the driver sizes, then you can simulate off-axis response and judge for yourself if the phase response is acceptable.

            Basically, if the phase is aligned on-axis, then the response will only drop as you move off-axis. If the phase is not aligned on-axis, then off-axis it will align, and at this angle the output will increase. This is because the alignment axis of the phase is not straight ahead, but at a slight angle, which may be of some benefit if the intended use for the speakers is above or below the listener.
            Don't waste your money on a new set of speakers, you get more mileage from a cheap pair of sneakers. Next phase, new wave, dance craze, anyways it's still rock and roll to me!

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            • #7
              Originally posted by isaeagle4031 View Post
              That isn't too shabby. Try adjusting the tweeter values just a bit and they will come right into line.
              So far it seems I would have to go from second order electrical to third on the tweeter to get near-perfect phase tracking. But do I need to? (Guess I will just add that cap and see..)
              Click image for larger version

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              • #8
                Originally posted by isaeagle4031 View Post
                The small cap did not knock that out?

                Yeah, but I have the LCR parts on hand and just kept them there as part of the learning experience.

                @decibel, will do.

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                • #9
                  You have fine frequency response (FR) throughout the crossover region so I wouldn't obsess over the phase. It's easy to caught up in the "I must have a super deep null" train of thought and forget a main reason for phase tracking is to prevent FR irregularities around the crossover region. Good luck with your project!

                  PS - I assume you measured/calculated the acoustic offset and entered that into PCD (as Z offset) along with the Y offset.
                  "Everything is nothing without a high sound quality." (Sure Electronics)

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                  • #10
                    Originally posted by Wushuliu View Post


                    Yeah, but I have the LCR parts on hand and just kept them there as part of the learning experience.

                    @decibel, will do.
                    Understandable. As far as 3rd order, given the somewhat low xover point, I would use that as a minimum anyway
                    https://www.facebook.com/Mosaic-Audi...7373763888294/

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                    • #11
                      Originally posted by isaeagle4031 View Post

                      Understandable. As far as 3rd order, given the somewhat low xover point, I would use that as a minimum anyway

                      Why? To protect the tweeter?

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                      • #12
                        Which version TW29? None of them like to go that low, they have a natural roll off that starts around 4K,
                        but then a large peak at around 1500, even if you get decent measurement it will not sound very good.

                        Also what are you basing your cap/coil ratios on?

                        All the SB stuff can sound fantastic but the tweeters can get naughty below 2K if not very sharply
                        filtered.

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                        • #13
                          You see even the much cheaper Seas (and the Transducer Labs) has a lot less distortion at 1K.
                          The SB tweeters are some of the best but I would never cross them below 3K at 12 or more dB
                          per octave.

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                          • #14
                            Huh, I thought one of their advantages was that they could be crossed low.

                            Can't cross below 3k?

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                            • #15
                              Here's the TW29 soft dome:
                              http://www.audioxpress.com/article/t...gh-end-tweeter

                              And here's the Be edition:
                              http://www.audioxpress.com/article/t...m-dome-tweeter

                              You have increasing distortion below 2kHz, but it is purely 2nd order. I wouldn't hesitate to use the TW29 with a 2nd order 2kHz crossover, 4th order acoustic rolloff, but no lower.
                              Don't waste your money on a new set of speakers, you get more mileage from a cheap pair of sneakers. Next phase, new wave, dance craze, anyways it's still rock and roll to me!

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