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  • #91
    Re: Best new midwoofer?

    You need to offset the driver, or add HUGE roundovers to smooth the baffle diffraction you are seeing in the plot.

    Other than that, you just have to live with it.
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    • #92
      Re: Best new midwoofer?

      Originally posted by internova View Post
      My measurement on a 8.5" baffle.

      [ATTACH]19827[/ATTACH]

      HD

      [ATTACH]19828[/ATTACH]

      both at 1 meter.

      I want to cross it at 25-2600Hz. How should I deal with the 1K bump and 1.2K dip? The FR is smooth except the 1K bmp and 1.2K dip. I put it in a 0.5 CF box. I listened to music for a while on a bare driver. It sounds forward because no BSC has been applied. But very listenable. Also seems like a candidate for lower order crossover if the tweeter can do it.

      Thoughts?

      Here is the impedance. The box is tuned to 40Hz.

      [ATTACH]19829[/ATTACH]
      The 1kHz hump is cabinet diffraction. The 1.2kHz dip is in the driver. It smooths out a bit off-axis, but passively there isn't anything you should do about the dip. Because of the off-axis behavior it will sound smoother than it looks in your plot and may not even be noticeable.
      Click here for Jeff Bagby's Loudspeaker Design Software

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      • #93
        Re: Best new midwoofer?

        You need to offset the driver, or add HUGE roundovers to smooth the baffle diffraction you are seeing in the plot.

        Other than that, you just have to live with it.
        I have 3/4" roundover. If I change the baffle to 9", would that be any better?

        Originally posted by Jeff B. View Post
        The 1kHz hump is cabinet diffraction. The 1.2kHz dip is in the driver. It smooths out a bit off-axis, but passively there isn't anything you should do about the dip. Because of the off-axis behavior it will sound smoother than it looks in your plot and may not even be noticeable.
        I'll take off-axis measurement. If I roll it off at 2.6K, the extension up to 15K looks "wasted"?

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        • #94
          Re: Best new midwoofer?

          Originally posted by internova View Post
          I'll take off-axis measurement. If I roll it off at 2.6K, the extension up to 15K looks "wasted"?
          It wouldn't be wasted, it would be a waste to play that woofer up to 15K though.

          2.6K is a good starting point.
          "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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          • #95
            Re: Best new midwoofer?

            Originally posted by Face View Post
            It wouldn't be wasted, it would be a waste to play that woofer up to 15K though.

            2.6K is a good starting point.
            Does it have advantage of rolling off the woofer a slower? The Revelator and Excel are smoother (regardless of audiable or not) in the 1K region to work. The Excel has to be rolled off quicker b/c of the breakup. Satori doesn't need to be. Satori's off-axis is slightly better than Excel 7" (Smaller driver) and extends deeper (almost as deep as the 7" Revelator in a slightly smaller cabinet). Of course, it's almost $100 more expensive.

            What did I get for the $100?

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            • #96
              Re: Best new midwoofer?

              ~$250 for a pair of tested samples.

              http://www.ebay.ca/itm/2-SB-Acoustic...item41606efeb5

              Pretty decent deal is someone likes this woofer but finds the price off-putting.
              https://www.youtube.com/channel/UCm2...oSKdB448TTVEnQ

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              • #97
                Re: Best new midwoofer?

                Originally posted by internova View Post
                Does it have advantage of rolling off the woofer a slower? The Revelator and Excel are smoother (regardless of audiable or not) in the 1K region to work. The Excel has to be rolled off quicker b/c of the breakup. Satori doesn't need to be. Satori's off-axis is slightly better than Excel 7" (Smaller driver) and extends deeper (almost as deep as the 7" Revelator in a slightly smaller cabinet). Of course, it's almost $100 more expensive.

                What did I get for the $100?
                For me, I see the extended frequency response as an opportunity to achieve a true transient perfect / minimum phase speaker by taking advantage of the inherently small phase rotation. This can not easily be done with very many drivers available today. It still takes some crossover design skills, but I know a guy that I'm confident can pull it off ;)

                The driver also offers excellent bass extension, which is a plus as well.
                Click here for Jeff Bagby's Loudspeaker Design Software

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                • #98
                  Re: Best new midwoofer?

                  Originally posted by Jeff B. View Post
                  For me, I see the extended frequency response as an opportunity to achieve a true transient perfect / minimum phase speaker by taking advantage of the inherently small phase rotation. This can not easily be done with very many drivers available today. It still takes some crossover design skills, but I know a guy that I'm confident can pull it off ;)

                  The driver also offers excellent bass extension, which is a plus as well.
                  Did you mean 1st order BW filter?

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                  • #99
                    Re: Best new midwoofer?

                    Originally posted by internova View Post
                    Did you mean 1st order BW filter?
                    No, but the driver could easily be used with a single coil given its flat response and impedance and provide a 1st order roll-off. The problem is, that's not likely to provide a transient perfect summation because you will have a hard time getting a tweeter to provide you with a true first order roll-off for very far. I was considering something a little more complex. Which means I will have to fire CALSOD back up on the old computer because I can't do this kind of circuit in PCD. I won't go into details now, but it doesn't use any all-pass delay ladders either.
                    Click here for Jeff Bagby's Loudspeaker Design Software

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                    • Re: Best new midwoofer?

                      Originally posted by Jeff B. View Post
                      No, but the driver could easily be used with a single coil given its flat response and impedance and provide a 1st order roll-off. The problem is, that's not likely to provide a transient perfect summation because you will have a hard time getting a tweeter to provide you with a true first order roll-off for very far. I was considering something a little more complex. Which means I will have to fire CALSOD back up on the old computer because I can't do this kind of circuit in PCD. I won't go into details now, but it doesn't use any all-pass delay ladders either.
                      Hi Jeff,

                      What are the pros and cons of a "transient perfect summation"? I guess what I'm saying is what are the sonic differences when compared to a non-transient perfect design? I don't think I've ever heard a transient perfect summation design before. Any commercial examples? Thanks.

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                      • Re: Best new midwoofer?

                        Hey, Jeff and everyone else in this thread!
                        Thought you might be interested in this Vifa I tested. It looks very, very good. I think it's a great contender to the Satori and about $100 cheaper.
                        http://techtalk.parts-express.com/sh...32#post1793932


                        I still would like to get my hands on one of these, though. I'll try build up some funds and give Madisound a call.

                        Thanks again for providing your data. When our powers combine, we are Captain Planet! errrr....

                        :D
                        ErinsAudioCorner.com

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