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GRS/Goldwood project: progress

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  • GRS/Goldwood project: progress

    Spent the afternoon measuring, listening and tweaking.

    No final crossover yet, but I will say that it is an extremely simple design and I am close to final right now.

    So far, there is a single coil on the woofer and on the piezo, I added a parallel resistor. Then a series resistor followed by a series capacitor. Four components, two of them resistors

    The FR of the piezo is pretty ragged. However, sitting here listening to some stuff I am very familiar with leads me to believe that ultra-flat tweeters are nice and all, but anything over 10k is increasingly less important.

    With the current iteration, the FR (with about 2db of baffle step correction) is +/- 3db from 300 - 6000 Hz.

    Because of the raggedness of the tweeter, I am using the woofer higher than is optimal, but this is not a design comprised of "optimums". For example, it uses a $8 woofer and a $2.50 tweeter so right off the bat, there is a whole of "not optimums" happening In any event, the woofer in this enclosure rolls off at an almost text-book perfect 3rd order BW @ 2800Hz with a single coil ;)

    WRT the woofer, when I posted some impedance measurements a week or two ago I commented on a ripple in the curve. That shows up on the FR measurements, but it is a dip, not a peak. Dips are less of an issue than peaks, or so I "hear". In any event, I used that old axiom for this entire design. I ignored dips created when taming peaks. The measured FR of this guy will scare some people. Let's just say I am understanding how these things work a little better. I am definitely an objectivist, but I am learning how to apply objective measurements to my subjective interpretation. This is why everyone should buy a measurement rig

    There is no annoying sibilance, and no obvious hint of "shouting through cupped hands" that I have heard from previous piezo designs. All in all, not bad for the money.

    Bass extension is not good. However, given that this design is targeted towards the newbie builder (the enclosure can be built with a skil-saw, jig-saw and screws - no fancy routing, no round-overs, basic dimensions) it is assumed that bass augmentation will already be present or coming very soon. Many newbies start with a powered subwoofer. In point of fact, I also have a pair of the GRS 12" poly cones (thanks Arlis) and will be designing a bass bin for these.

    Even with only 2db of BSC, these are low sensitivity speakers so I would suggest finding a cheap, used HTR to power them. At the price, a guy could build about five of these (if you know what I mean).

    OK, back to listening and tweaking. I am at the switch-out-and-see stage.

    I will leave you with a little sneak peek:
    Don't listen to me - I have not sold any $150,000 speakers.

  • #2
    Re: GRS/Goldwood project: progress

    Very cool, Johnny. I think it's fun sometimes to try to build something worthwhile out of inexpensive or "junk box" parts. Looks like good inexpensive DIY fun to me!

    Comment


    • #3
      Re: GRS/Goldwood project: progress

      This is a cheap project even by my standards
      Don't listen to me - I have not sold any $150,000 speakers.

      Comment


      • #4
        Re: GRS/Goldwood project: progress

        ill have them up there monday john. got the mids too. see new thread.
        " 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


        • #5
          Re: GRS/Goldwood project: progress

          Send me your mailing address, Arlis.
          Don't listen to me - I have not sold any $150,000 speakers.

          Comment


          • #6
            Re: GRS/Goldwood project: progress

            Very cool project Johnny. I think it might help someone jump into the DIY speaker world that may have otherwise been reluctant. I can see someone thinking "Man, what if I spend $200 on parts and my novice woodworking skills make them sound like crap? I should just spend my $200 at Best Buy." With a project like this, like you said, even a person with little to no experience and some basic tools can jump in and try it out without spending too much Jack. Bravo!
            Craig

            The lowest possible F3 box alignment is not always the best alignment.

            Designing and building speaker projects are like playing with adult Lego Blocks for me.

            Comment


            • #7
              Re: GRS/Goldwood project: progress

              That is a large part of my motivation, Craig. My other motivation was to address the following though...

              I am sure a lot of people buy the cheapest speakers they can, throw them in a box with an "off-the-shelf" and they are disappointed with the results - or even worse, they are ecstatic with the results. With this project, it combines a couple of the cheapest drivers out there with a computer designed crossover and cabinet (I love saying that). A "proven" design, as it were. So many people come to the forum and they have a budget of $100 or so. This project will let them build a pair of reasonably good sounding speakers at a very reasonable price, and will not require any special tools or knowledge of acoustics. They are even voiced next to the wall, since that is where a lot pf people end up placing their speakers anyway.
              Don't listen to me - I have not sold any $150,000 speakers.

              Comment


              • #8
                Re: GRS/Goldwood project: progress

                It looks like a tiny Econowave. Great project.

                Comment


                • #9
                  Re: GRS/Goldwood project: progress

                  econowave jr. :D
                  " 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

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