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It’s that time audio enthusiasts! Registration for the 2019 Speaker Design Competition is now open! Visit midwestaudiofest.com for details and to list your speaker project. We are excited to see all returning participants, and look forward to meeting some new designers this year, as well! Be sure your plans include a visit to the Parts Express Tent Sale for the lowest prices of the year, and the Audio Swap Meet where you can buy and trade with other audio fans. We hope to see you this summer! Vivian and Jill
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3-Way Active - High WAF - Hi-Vi-Fas

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  • #46
    Re: 3-Way Active - High WAF - Hi-Vi-Fas

    I just meant that virtual sources from baffle diffraction, reflections off grills, and that sort of thing would tend to be higher magnitude. I didn't really mean you should worry about that. It's all mostly settled once you choose drivers anyway. I think a decent "rule of thumb" strategy is to measure or estimate the two frequency ranges where the mid matches the woofer and the tweeter in dispersion and try to cross there, adjusting as needed to meet the bandwidths the drivers can handle. I haven't really looked at your project that carefully to be honest, just wanted to comment on the graphs because I thought they were kinda misleading.

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    • #47
      Re: 3-Way Active - High WAF - Hi-Vi-Fas

      Those bases look great, they almost disappear against the dark wood floor. Nice looking setup.
      My modest builds:
      Armadillo TM, A.K.A. Lil' Dillo
      Tarkus/Armadillo build #2
      Armadillo Center Channel
      Au-Rock-O Sub
      Tarkus
      Staining MDF tutorial

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      • #48
        Re: 3-Way Active - High WAF - Hi-Vi-Fas

        Thanks for all the kind feedback. Here's some pics of the guts of the entertainment center.

        This is the HTPC side - Running a i5-2550k @ 4.2ghz with 18TB of storage. Audio comes from an Asus Xonar D2X locked in @ a native bitrate of 16bit-44khz since the critical listening I do to is @ that rate/resolution. I've since added 2 intake fans to the holes on the right. Air is designed to travel from the right side to the left side, and exhaust there. It is a very positive pressure design, and since it is so big, I rely on localized directed air on components that need it, such as the hard drives, CPU, etc. The intake/exhaust flow is mainly to keep the ambient temperature in the case acceptable, not to actually cool anything specifically.



        This is the audio side. Running a JL XD 600/6 amplifier with a 60amp 13v power supply. Processing is done by a pair of MiniDSP units. I have a delay/power regulation unit in the chain as well. At power up, it will immediately send regulated power to the DSP units, then power the amp on after a few second delay. Shutdown is done in reverse.



        I've been struggling with tuning - crossover points, levels etc - using a RTA and a calibrated mic. I've had good success doing this in many cars with active crossovers, but I'm having a bit of trouble with this. I'm able to get the response very flat with no issue (one of the easy parts of using a 3-way with good drivers), but it doesn't sound "right". The sound feels rather dead and the low frequency extension is very one-note. I used the same ported alignment as the OS MTMs (also using 2 of the same woofer), so I'm not sure what the issue is. I'll keep at it (can't wait for the Active Crossover Design tutorial session at the upcoming get together).

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        • #49
          Re: 3-Way Active - High WAF - Hi-Vi-Fas

          Originally posted by devinkato View Post
          I've been struggling with tuning - crossover points, levels etc - using a RTA and a calibrated mic. ...... I'm able to get the response very flat with no issue (one of the easy parts of using a 3-way with good drivers), but it doesn't sound "right". The sound feels rather dead and the low frequency extension is very one-note.
          Hmmmm... I could just be clutching at straws here, but two things come to mind:

          1. What about the room dimensions? Have you done any calculations on Axial, Tangential and Oblique Modes? There are several internet sites that have this available for your use. (I could send you a quick and dirty version I have for MS Excel.) Certain ratios of Length to Width to Height will produce fabulous results while others can make the sound quite bad (regardless of ANY speakers used in that room.) Once you understand those modes (Axial contribute the most) you can attempt to make adjustments so that you will not stimulate the problematic (coincident) modes. Or even create a Helmholtz resonator to help with certain problem frequencies. Ask the TT forum for help after you run through the calculations.

          2. The other important thing that people sometimes forget about is the ratio of Reflection to Absorption to Diffusion. A "normal" sounding room will have a good balance of all three. Too much of one, or not enough of another will cause some of the problems that you are describing.


          Hopefully this helps.

          Your speakers look friggin awesome. Nice job.
          ~Marty

          Baby Eidolons
          Sapphos
          Cables (Post #54)
          Other speakers (Post #21)
          Design Thoughts (Posts: 6,10,13,33,35)
          Boundary Augmentation
          Dispersion/Interference

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          • #50
            Re: 3-Way Active - High WAF - Hi-Vi-Fas

            A few tips:

            - did you take a nearfield measurement of a woofer to verify Fb? (or verify with impedance measurement, etc.)

            - Try to set yourself up to take some nice clean gated measurements with the speaker way out in the room and on the floor pointed up (and propped up enough to leave to port clear). Measure up and down the vertical axis. That will give you an idea of how your phase tracking between drivers is.

            - Remember to turn it up. Speakers that have flat on-axis response in-room tend to sound pretty dull at low volumes.

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            • #51
              Re: 3-Way Active - High WAF - Hi-Vi-Fas

              Originally posted by dtruck View Post
              A few tips:
              - did you take a nearfield measurement of a woofer to verify Fb? (or verify with impedance measurement, etc.)
              How do you go about verifying Fb? I did some searching, and know how to calculate it, but how do you measure in the real world? Play a tone and look for a peak?

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              • #52
                Re: 3-Way Active - High WAF - Hi-Vi-Fas

                Just put your mic right up 1cm from a woofer cone. You should see a deep notch in response at Fb.

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                • #53
                  Re: 3-Way Active - High WAF - Hi-Vi-Fas

                  holy heck your project is awesome.... makes me embarrassed of my projects... but... active 3 ways all the way

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