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Adding tweeter to Wolf's PC Speakers for better off-axis response + A few semi-related questions

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  • Adding tweeter to Wolf's PC Speakers for better off-axis response + A few semi-related questions

    Hey folks, so my next project is to build a single Wolfs PC speaker for a portable speaker box to carry around with me.
    Thing is, the speaker will always be facing straight up and be at about waist level. Because it'll be on a table with people listening around the table.
    So it cannot be facing in a particular direction. It must be omni-directional.

    Soooo.... I want to add a tweeter.
    But my enclosure width is such that I can only add a 2" overall diameter tweeter. No room for anything else.
    So I'm looking at this tweeter:
    Visaton SC5-8 Shielded 1/2" Polycarbonate Tweeter 8 Ohm

    http://www.parts-express.com/visaton...8-ohm--292-552

    Now one problem is it's rated at 90dB efficiency while the PC Speakers NS3 is rated at just 80dB.
    Can I get away with just using a crossover calculator to design a Butterworth 2nd order two-way.
    And then use an L-Pad? Or could someone help me with a crossover design?

    ALSO, what about a BSC filter since this will just be a 3Pi situation without any nearby walls for bass reinforcement?
    Should I design one?

    And last question, will this really handle up to 80 watts max?
    I'd like to get it to play as loud as possible, maybe up to 100dB @ 3'.
    I don't see that the PC Speakers have any kind of High Pass filter though.
    Maybe I should add a passive 12db filter at 80hz?

    Speaker will be used for watching TV shows as well as various music.
    With some music putting out beats around 30hz. Though I don't expect to hear that, I also don't want the NS3 blowing on me.

  • #2
    Remember that treble is more directional, and would require more than one tweeter for an Omni setup. You might not want to get that far into it.
    Remember that Omni speakers don't require BSC, as they emit sound in all directions. There is no wraparound drop of 6dB. On a table you will get boundary reinforcement.

    I don't know how loud they will get personally, BUT- the 500uF cap and small sealed volume acts as a very stiff air-spring and protects the driver very well. At an Iowa DIY, as told to me by bkeane, he had a set of PC cubes there hooked up to a Theta Dreadnought amplifier, and they TRIED UNSUCCESSFULLY to blow them up. There is no extra HP required, as the size and cap do the job well enough. I doubt you'll get response to 30Hz, but 55-65 Hz range is not unheard of.

    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:
    https://app.photobucket.com/u/wolf_teeth_speaker

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

    Comment


    • #3
      Oh, you'll probably be -10 to -15dB down anyway (by looking at the of-axis chart). Also, I'd say sitting face-up on a table will be more like a 2pi environment (like an "in-wall"). I'd just try an appropriate cap (to protect the tweeter) for starters and see how it sounds.

      I think you'd be looking at more like 20-25w max., since the woofer will get most of the energy anyhow. Probably shy of 95dB at 20w at 3ft.

      Comment


      • #4
        If you want a speaker that approximates the PC with a tweeter, my Helium design is an option.
        Keep an open mind, but don't let your brain fall out.

        Sehlin Sound Solutions

        Comment


        • #5
          Thanks, Guys!

          Originally posted by scottsehlin View Post
          If you want a speaker that approximates the PC with a tweeter, my Helium design is an option.
          I have no idea how I missed your build in all of my Googling over the last few weeks.
          This is PERFECT for what I'm trying to do!
          Thank you.

          Comment


          • #6
            most spakers have tweeters anyways wh ybuy spakers with mussing parts sounds likr broken things

            Comment


            • #7
              Originally posted by 69FireBird
              most spakers have tweeters anyways wh ybuy spakers with mussing parts sounds likr broken things
              You gotz to much highr learnin fer this pkace Sent from my SCH-S968C using Tapatalk
              craigk

              " Voicing is often the term used for band aids to cover for initial design/planning errors " - Pallas

              Comment


              • #8
                This is an excellent case of needing to carefully choose speakers that really suit the needs. "Teleconferencing" requires a deft touch in both speakers and usually "boundary" mics (if I understand your use correctly).

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