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Old system - off the shelf crossover measurements

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  • Old system - off the shelf crossover measurements

    After giving up my Supernova Minimus speakers to their new home, I had to pull out my old Nova 15's from storage in order to have some music in my listening spot. These are the first real speakers I ever got, back in about 1989 or so. They have traveled with me everywhere I moved, survived college (sort of) and a whole bunch of life until they were resigned to storage when I built up the Supernovas. They have had several woofers and tweeters, which I abused heavily, destroyed, and replaced again. The cabinets show lots of wear and tear from over the years too, which is why I went with my grandmother's pair for the Supernovas.

    The current incarnation was populated many years ago, well before measurement gear was cheap and the simulation tools were available to develop a proper crossover. Consequently, my design process was to use the specs of the drivers, match the woofer and tweeter published range and sensitivity spec, and plop in a textbook off the shelf crossover. These have a cheap MCM 8" foam surround woofer, and what I believe is an old Dayton silky tweeter wired with a 2kHz off the shelf 8 ohm crossover. They've always been used with a sub, so the lack of BSC wasn't a problem, and I since our ears adjust pretty easily I've never noticed any major issues with the frequency response.

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    Today I decided to do some ARTA sweeps to see how they actually perform. To my surprise, not too terrible.
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    Gated and unsmoothed response measured at 40 inches on tweeter axis is about +-6 dB. Not nearly as tight as a proper design, and shows the poor crossover mis-match around 3.5k and a couple extra dB of tweeter output, but I was pleasantly surprised.

    Distortion?
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    The Supernova's blow this out of the water, but nothing is jumping out as terrible. The rise near 4k is likely unmanaged woofer breakup, but I'm not taking the time to do individual driver measurements to confirm.

    These will be my basement speakers for now, and light a fire for me to build my 3 way project called the Anarchies sooner than later. I will run the YPAO calibration my receiver can do to compensate that +-6 dB and integrate the sub better. That should help scratch the HiFi itch for now.

    Also... I have a set of baffles ready to complete for these cabinets too. They'll be the new home of a part of DA215 woofers, with those same Silkies and a proper crossover design. These will then live on as a hand me down to my son, whenever he is stable enough to have a home for them.
    Electronics engineer, woofer enthusiast, and musician.
    Wogg Music
    Published projects: PPA100 Bass Guitar Amp, ISO El-Cheapo Sub, Indy 8 2.1 powered sub, MicroSat, SuperNova Minimus

  • #2
    Several things working against that speaker (recessed baffle, not recessed tweeter, off the shelf xo, etc.) yet surprisingly not a hideous measurements. Man that port looks tiny
    Last edited by PWR RYD; 09-01-2022, 06:33 PM.
    Craig

    I drive way too fast to worry about cholesterol.

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    • #3
      Originally posted by PWR RYD View Post
      Several things working against that speaker (recessed baffle, not recessed tweeter, off the shelf xo, etc.) yet surprisingly not a hideous measurements. Man that port looks tiny
      Yeah... they chuff like crazy if you ask for bass. Even the tiny motor original Realistic woofer had that problem.

      I did the YPAO adjustment and did some listening last night. Acceptable. This may be in my head, but I swear I can hear the distortion is higher relative to the Supernovas. These will just fatigue you quicker.
      Electronics engineer, woofer enthusiast, and musician.
      Wogg Music
      Published projects: PPA100 Bass Guitar Amp, ISO El-Cheapo Sub, Indy 8 2.1 powered sub, MicroSat, SuperNova Minimus

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      • #4
        If it means anything I think those were my favorite at the sdc.
        I'm certainly not good at this. Just stubborn enough to keep going.

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        • wogg
          wogg commented
          Editing a comment
          It does, thanks a lot!
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