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peerless 830875 and fountekcd3.5H mtm

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  • peerless 830875 and fountekcd3.5H mtm

    well i have had these woofers for many months and the tweeter for a few weeks and thought it was time to get busy.
    i whipped up a test box yesterday from mdf and plywood i had on hand.



    did some measuring last night with the omnimic and started a sim with pcd. what a great tool.
    the omnimic graph is raw woofers and tweeter and summed with crossover in place.

    " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

    Quote Originally Posted by hongrn. Oct 2014
    Do you realize that being an American is like winning the biggest jackpot ever??

    http://www.midwestaudioclub.com/spot...owell-simpson/
    http://s413.photobucket.com/albums/pp216/arlis/

  • #2
    Re: peerless 830875 and fountekcd3.5H mtm




    " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

    Quote Originally Posted by hongrn. Oct 2014
    Do you realize that being an American is like winning the biggest jackpot ever??

    http://www.midwestaudioclub.com/spot...owell-simpson/
    http://s413.photobucket.com/albums/pp216/arlis/

    Comment


    • #3
      Re: peerless 830875 and fountekcd3.5H mtm

      these are horizontal only

      " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

      Quote Originally Posted by hongrn. Oct 2014
      Do you realize that being an American is like winning the biggest jackpot ever??

      http://www.midwestaudioclub.com/spot...owell-simpson/
      http://s413.photobucket.com/albums/pp216/arlis/

      Comment


      • #4
        Re: peerless 830875 and fountekcd3.5H mtm

        3.5H has slightly raised response 10khz to 20khz which adds a bit of "air" or "sizzle"
        I didn't understand the phrase: the omnimic graph is raw woofers and tweeter and summed with crossover in place
        You took the raw woofer response, then tweeter and then both with the crossover? Why is the tweeter response so rolled off on the top octave?
        http://www.diy-ny.com/

        Comment


        • #5
          Re: peerless 830875 and fountekcd3.5H mtm

          the thin lines are woofers and tweeter raw. the thick blue is both with a crossover in place. you can see they match on the high end. i dont know why it rolls off but i suspect its inherent to the omnimic because my last two builds did the same. i just checked it from about 3" and its the same. there is plenty of sizzle. best tweeter i have ever used.
          it has a clarity to it.
          " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

          Quote Originally Posted by hongrn. Oct 2014
          Do you realize that being an American is like winning the biggest jackpot ever??

          http://www.midwestaudioclub.com/spot...owell-simpson/
          http://s413.photobucket.com/albums/pp216/arlis/

          Comment


          • #6
            Re: peerless 830875 and fountekcd3.5H mtm

            it tuns out that the sine sweep gives much better results. Bill DID tell me this, i just didn't listen. mo better?

            this one with 4 ohms on the tweeter
            " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

            Quote Originally Posted by hongrn. Oct 2014
            Do you realize that being an American is like winning the biggest jackpot ever??

            http://www.midwestaudioclub.com/spot...owell-simpson/
            http://s413.photobucket.com/albums/pp216/arlis/

            Comment


            • #7
              Re: peerless 830875 and fountekcd3.5H mtm

              Wow that looks really flat! Good work

              रेतुर्न तो थे स्रोत
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              • #8
                Re: peerless 830875 and fountekcd3.5H mtm

                This does look much better. Would you mind if I make a couple of suggestions?
                you have a bottomless notch on the woofer? Sorry, I am not very familiar with PCD.
                http://www.diy-ny.com/

                Comment


                • #9
                  Re: peerless 830875 and fountekcd3.5H mtm

                  i was hoping you would. (not sarcasim) i know you are using the same fountek.
                  bare in mind, i will start over and measure with the sine sweep in the morning.
                  " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

                  Quote Originally Posted by hongrn. Oct 2014
                  Do you realize that being an American is like winning the biggest jackpot ever??

                  http://www.midwestaudioclub.com/spot...owell-simpson/
                  http://s413.photobucket.com/albums/pp216/arlis/

                  Comment


                  • #10
                    Re: peerless 830875 and fountekcd3.5H mtm

                    Well, New Year is coming up.
                    I would look at the woofer break up very closely.
                    http://www.parts-express.com/pedocs/...ifications.pdf
                    It appears to be around 4200hz and mostly on axis. Look in to Far Field response of the woofer with the crossover on and slightly off axis. Get the CSD of the woofer with and without crossover from around 30" mic position or so. Also, do the distortion sweeps of the woofer with and without crossover on and off axis. It'll bring up more info on how effective the slope+notch are.
                    Same thing with the 3.5H

                    Fountek has a problematic issues with the rear chamber (I doubt the foil itself rings but who knows) accompanied by distortion spike. That has to be sloped out from audibility. I would pay very close attention to it. It'll sound crystal clear after you deal with that spike.
                    http://www.diy-ny.com/

                    Comment


                    • #11
                      Re: peerless 830875 and fountekcd3.5H mtm

                      Arlis or r-carpenter...I have a few questions:

                      1. Why second order on the woofer and third for the tweeter? Is it for better protection for the Fountek?

                      2. Why would you cross one driver over at 2.5KHz and the other at 3KHz? Why not cross both at the same frequency?

                      3. Why Butterworth slopes and not 4th order LR slopes?

                      I'm not critiquing, or criticizing your design at all, just trying to understand more about crossovers and PCD.

                      Nice work, by the way!

                      Thanks...

                      Comment


                      • #12
                        Re: peerless 830875 and fountekcd3.5H mtm

                        one somtimes has to go higher order to get good phase tracking. i let the drivers show me the way. i dont really know all the rules about this so i just guess and see what works.
                        " To me, the soundstage presentation is more about phase and distortion and less about size. However, when you talk about bass extension, there's no replacement for displacement". Tyger23. 4.2015

                        Quote Originally Posted by hongrn. Oct 2014
                        Do you realize that being an American is like winning the biggest jackpot ever??

                        http://www.midwestaudioclub.com/spot...owell-simpson/
                        http://s413.photobucket.com/albums/pp216/arlis/

                        Comment


                        • #13
                          Re: peerless 830875 and fountekcd3.5H mtm

                          foxfire
                          There are no set slopes and by the book design necessities. Individual driver responses are EQed by means of passive crossover (in this project) until their individual and summed up responses are within a reason. Meaning that the response of the loudspeaker is fairly flat and without serious aberrations. The off axis response should be looked at too. And then non linear as well. Oh, and impedance also. aNd Phase.
                          Drivers do not roll off gradually. Roll off character depends on the motor and inherit driver response. So the crossover implementation should address these issues and hopefully make smooth transition between the two.
                          It's not only the protection for Fountek, it's also making sure that all "unclean" so to speak, artifacts are filtered out and with ribbons, most of these artifacts are down low. So, sharper slope provides better filter to stop the nastiest from getting through.
                          Why not cross them at the same frequency? Because you kinda trying to mate a cow to an antelope and some sideways positioning may be needed.
                          http://www.diy-ny.com/

                          Comment


                          • #14
                            Re: peerless 830875 and fountekcd3.5H mtm

                            Really nice rebate template Arlis. ;)

                            Should be a fine sounding system when you get everything ironed out.

                            Ron
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                            The good thing about science is that it's true whether or not you believe in it. - Neil deGrasse Tyson
                            http://www.youtube.com/watch?v=cjuGCJJUGsg

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                            • #15
                              Re: peerless 830875 and fountekcd3.5H mtm

                              Originally posted by foxfire3 View Post
                              2. Why would you cross one driver over at 2.5KHz and the other at 3KHz? Why not cross both at the same frequency?
                              As I understand it, those are the frequencies that the filters start to roll off at, but it's not a dead stop, more of a gradual slope (as you can see in the transfer function graph). So what you actually end up with is a bit of overlap between the 2 drivers where the roll off of one driver "crosses" the other. So the filter frequencies are 2.5k and 3k, but the actual "crossover frequency" is somewhere in between. The idea is to set your filters far enough apart, so that the area where the drivers are playing the same frequency sum together, without being louder than the other frequencies above or below that. If they were the same frequency, there would be too much overlap, and you'd have a peak in the response. That's my basic understanding of why it works anyways.
                              My modest builds:
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