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Continuuation. (active continuum 3way)

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  • Continuuation. (active continuum 3way)

    I have just finished converting my continuum 3way to an active setup and decided to do a short easy (hopefully) to understand write up on the process I used. This process can be used with any passive speaker that you want to convert to an active speaker using a mic and measurement program (I recommend omnimic for ease of use although any decent mic and program that measure frequency response can be used) and your choice of active processor (I am using a minidsp, other active processors may vary but still should work in much the same way).

    You will also need amps but I assume you know all the gear that will be needed and how to hook it all up. If not there is plenty of info on that elsewhere or just ask on the tech talk part of the forums.

    I will update this thread soon so stay tuned.

    Original project can be found here http://techtalk.parts-express.com/fo...ntinuum-kaboom

  • #2
    Step one is to measure overall response of the speaker with the crossover in place. This is for a reference to be sure your results are close to the original response when done. Be sure to save the FRD measurement to use as an overlay in the steps to come.

    The measurement doesn't need to be perfect but the mic should be placed in the same spot as this measurement when taking the final measurement. I chose 2.5 foot from the tweeter because it gave me a clean response through the mid to tweeter crossover area. I wasn't too worried about the woofer region as it is hard to get good in room measurements that low and I didn't think it would be too difficult of an area to get right using this method.

    Here is my measurement of the overall response. (This is not the proper width cab for the mid and tweeter so it may not look as smooth as the original continuum measurement)
    Attached Files
    Last edited by killa; 11-07-2016, 05:13 PM.

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    • #3
      The next step is to measure each individual driver with its section of the crossover in place. Remember to disconnect the other drivers that are not being measured (ex. when measuring the tweeter disconnect the mid and woofer) Don't forget to save the FRD measurements for the steps to come.

      These measurements will be taken nearfield right next to the cone to get as clean as a response as possible. Note the mic positions as the next step will need the mic placed as close to the same spot as possible. Don't worry about how the response looks too much as long as there isn't a lot of noise.

      These are the nearfield responses of my tweeter, mid, and woofer
      Attached Files
      Last edited by killa; 11-07-2016, 05:14 PM.

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      • #4
        Now we are going to use the nearfield measurements taken in step 2 that we saved earlier. Pic the FRD file of the driver you want to work with (the one that was measured with crossover in place, see step 2). I am going to start with the mid (since I forgot to save images of this part for the other two drivers).

        Add the FRD file to your measurement graph (omnimic allows you to do this, not sure about other programs). It will look like the pic below (the black response on the graph)

        After adding the FRD it is now time to measure the driver without the crossover. This combined with the FRD file will show us the difference in response between the raw and filtered driver and allow us to use signal processing to shape the raw response to the filtered response.

        Here is the raw and unfiltered response
        Attached Files
        Last edited by killa; 11-07-2016, 05:37 PM.

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        • #5
          From here on out it is just a matter of shaping the raw responses with signal processing and measuring to see if it matched the FRD we measured in step 2. Omnimic allows you to do this on the fly as it keeps doing repeated measurements every second or so.

          I already knew what slopes Jeff used on the original design (12Db LR) so I input those and just adjusted the crossover frequency up and down until I got the same slopes. This got me close but not perfect. To get things even closer I had to play with the EQ settings some.

          Little tip If your response levels don't match up well (ex. your raw measurement is hotter by a few DB) you can use your DSP to turn the volume down to match the overlay.

          Here is where I ended up with the mid
          Attached Files
          Last edited by killa; 11-07-2016, 05:59 PM.

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          • #6
            Here are the the remaining drivers after I did the above (step 4). As you can see I was able to get a pretty good match with all three drivers.
            Attached Files
            Last edited by killa; 11-07-2016, 06:04 PM.

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            • #7
              Step 5. Now that we have all the drivers EQed and matched to the original responses we need to do a final measurement of the overall response to adjust our levels and to check to make sure final response matches the original response.

              In this step we will use the measurement taken in step 1 and add that to the response graph (same way we did in step 3). Set the mic up in the same position as step ! and start taking measurements. Then we simply adjust the output levels so they match the overlay. In my case I adjusted the output of the DSP so that the midrange output matched my overlay since it's level was already pretty close. This left the tweeter very hot so I turned the tweeter level down to match the overlay also.

              My woofer I just kind of eyeballed the squigglies so they were close to matching. I knew my filters were good as far as xo slope so it would just be a matter of listening by ear to adjust the level.

              Here is my final response and a inverted tweeter response. These particular measurements weren't very clean but get the idea across.
              Attached Files
              Last edited by killa; 11-07-2016, 06:24 PM.

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              • #8
                If anything is unclear let me know and I will attempt to fix it. Note, I did say attempt
                Last edited by killa; 11-07-2016, 06:28 PM.

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                • #9
                  I tried to delete my No. 8 reserved slot but for some reason it wouldn't let edit it lol.

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                  • #10
                    Nice... good to see an uptick in active projects...!!! So any apparent benefit to going active over passive?

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                    • #11
                      I've done a couple fully active builds, I prefer passive, honestly. Active works if you need to hammer FR into submission, or you're doing something out of the box, but I prefer passive crossovers to active in terms of simplicity (anyone with an amp can use them) and simplicity of the design (active can become super complicated fast with phase adjustments and whatnot).

                      रेतुर्न तो थे स्रोत
                      return to the source
                      leviathan system thread
                      deadhorse thread
                      shockwave build thread

                      instagram :: greywarden_13

                      in war, victory . . . in peace, vigilance . . . in death, sacrifice.

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                      • #12
                        From this experiment I would say yes there are benefits. I almost don't want to say this but I do hear more detail in the sound. The thing is I can't be sure if it is because of going active or because I am using different equipment. I was going through a topping DAC to an Emotiva preamp, and then of course an amp (outlaw audio 7075 which if I remember correctly is a rebranded ATI design). The minidsp I use has it's own DAC/volume control so I just go straight to that with a digital source, then to the amp. This eliminates the need for the topping and preamp.

                        The other major pro is the ability to EQ and shape response much more easily than a passive network could. You can also do things a passive can't do.

                        I do agree with greywarden though that it can get complicated quickly depending on what the user wants but for 2 channel music it isn't too bad.

                        I will also add that if i were to put together my ultimate 2 channel music system it would be active.

                        Also if anyone is interested here is a decent review and look at the DSP I am using

                        http://diygeezer.com/minidsp-4x10-hd-review/

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                        • #13
                          The only thing you can't do in a passive xover is boost or increase level of output relative to the input. Passives only cut and contour.
                          That said- I also tend to prefer passives.

                          Later,
                          Wolf
                          "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                          "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                          "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                          "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                          *InDIYana event website*

                          Photobucket pages:
                          http://photobucket.com/Wolf-Speakers_and_more

                          My blog/writeups/thoughts here at PE:
                          http://techtalk.parts-express.com/blog.php?u=4102

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                          • #14
                            Yes you can do anything with a passive as long as the impedance doesn't go too low. I think it would be interesting to do this with that speaker you had that was used for testing the sound of different crossover parts.

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                            • #15
                              Uhm- which one? Cecropia or Attitudes?

                              Really though, I know what you mean.
                              Wolf
                              "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                              "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                              "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                              "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                              *InDIYana event website*

                              Photobucket pages:
                              http://photobucket.com/Wolf-Speakers_and_more

                              My blog/writeups/thoughts here at PE:
                              http://techtalk.parts-express.com/blog.php?u=4102

                              Comment

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