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  • inexpensive vintage 2-way

    This is the first project I've posted, so here goes

    A friend of mine that I work with was chatting with me and said he was searching Craigslist for a pair of speakers for his garage, looking to spend around $50 / pair. I saw this as a perfect opportunity for a project. He agreed to let me build him something as opposed to buying something worn out, made of half inch chip board, and possibly stolen..

    I knew he liked heavier music like Metallica, Tesla, etc. and that he is a huge fan of the sound of the big floor speakers of days past, so I tried to recreate that style speaker, but better than most cheapos, in a smaller form to work in the garage.

    Drivers:

    I opted for an 8" woofer and a tweeter. I figured that this gave me the most woofer I could find to work in a two-way with a super inexpensive crossover option, as well as work well for his music choice.

    I chose the MCM 55-2971 (sorry PE, just couldn't argue with a $7.50 woofer for this project..) 8" poly cone woofer. For the price, the specs are very good, although being realistic, I don't believe for a minute that the specs are completely accurate..

    I wanted a paper cone tweeter because I wanted that vintage sound, and for the price I didn't have much for options. I didn't want a piezo and don't much care for the "ticky" sound of mylar semidomes. I saw the Goldwood GT25 and was satisfied with how it would likely work for this project and it had a respectable power handling. In PCD, I was able to make it blend with the MCM 8 relatively well with just a cap.

    Crossover:

    To keep budget, any inductors were out. I used PCD7 and was able to allow the woofer to roll off naturally and get by with a first order on the tweeter. I used a 3.3uf poly cap. This made for a higher crossover point than typically desirable, but figured it was worth a shot, and worked out well. I physically aligned the coils, so driver alignment was factored, and the tweeter was wired in positive polarity.

    Cabinet:

    Menards has some sanded finished pine plywood that has been looking interesting to me to work with, was relatively cheap when on sale, and was very easy to work with. I used 3/4" throughout. It wasn't entirely void free, but wasn't bad at all. The volume ended up being about 1.1 ft3 gross, tuned to 41 hz. This project was an opportunity where "acoustic ratio" proportions would work, so I used them in the design. The cabinet is air nailed, glued, braced, and caulked. It doesn't ring at all and is solid and dead. The port is a slot style on the front bottom. The upper portion is stuffed. I had stuffing throughout, but sounded better with an empty chamber behind the woofer.

    I wanted to align the driver coils, so I fabricated a wave guide, which was a ton of work, but turned out well. The cabinet was stained, but the guide was sprayed with Rustoleum bedliner, which gives a horn look and texture.

    I covered the drivers with grilles I made using cloth and soft copper tube made into a ring. He wanted grilles, so I made a set from cloth and 1/4 inch hardboard.

    Listening:

    All in all, they sound very good. They have a very spacious sound that isn't localized and stages very well. The bass is solid and not boomy at all. My only complaint is that the midrange lacks attack and seems to be a little soft. I attempted reversing tweeter polarity and that was not good at all. I'm certain that a more proper crossover could remedy this if budget allowed. The tweeter initially had a bright laserbeam hotspot, but behind the ring grille over it, i affixed a small cotton ball in the center, in front of the dustcap, which resolved that quite nicely. The whole system sounded worlds better after about 24 hours of break-in.

    My final thoughts:

    They sound much better than they have any right to for the price. Underestimating lumber, shipping, and not initially pricing in grilles, I was slightly over budget, but still not far off. They are fun and pleasant to listen to, and frankly I don't really want to part with them after listening to them for 3 days. I bring them to the guy today for his first look and listen, wish me luck! :D


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    Last edited by dynamo; 12-03-2013, 08:49 AM.
    Projects:

    transcenD: http://techtalk.parts-express.com/fo...5035-transcend
    Summits: http://techtalk.parts-express.com/sh...75-The-Summits
    References: http://techtalk.parts-express.com/sh...-My-References
    Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

  • #2
    Re: inexpensive vintage 2-way

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    Projects:

    transcenD: http://techtalk.parts-express.com/fo...5035-transcend
    Summits: http://techtalk.parts-express.com/sh...75-The-Summits
    References: http://techtalk.parts-express.com/sh...-My-References
    Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

    Comment


    • #3
      Re: inexpensive vintage 2-way

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      Projects:

      transcenD: http://techtalk.parts-express.com/fo...5035-transcend
      Summits: http://techtalk.parts-express.com/sh...75-The-Summits
      References: http://techtalk.parts-express.com/sh...-My-References
      Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

      Comment


      • #4
        Re: inexpensive vintage 2-way

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        Projects:

        transcenD: http://techtalk.parts-express.com/fo...5035-transcend
        Summits: http://techtalk.parts-express.com/sh...75-The-Summits
        References: http://techtalk.parts-express.com/sh...-My-References
        Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

        Comment


        • #5
          Re: inexpensive vintage 2-way

          The first chart is no baffle step factored for the woofer, which may not be far off considering they are probably going to be placed in a garage corner.

          The second is assuming 3db in baffle step, and the third is all 6db of loss factored in.


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          Projects:

          transcenD: http://techtalk.parts-express.com/fo...5035-transcend
          Summits: http://techtalk.parts-express.com/sh...75-The-Summits
          References: http://techtalk.parts-express.com/sh...-My-References
          Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

          Comment


          • #6
            Re: inexpensive vintage 2-way

            This, I like. Awesome job.

            Those sooperdooper cheap MCM poly woofers can perform very well.
            Don't listen to me - I have not sold any $150,000 speakers.

            Comment


            • #7
              Re: inexpensive vintage 2-way

              Need to get my **** in gear with the 4 I have. Nice work!!!!!!

              Edit: I really like the write-up too. Makes awesome sense and plays perfect to the strengths of cheap-o drivers. Very, Very, well done!

              Edit Edit: What do you think of that GW tweeter? It got quite a bit of play in my "lil' Brits" using a $0.69 buyout woofer. I love it, actually and it may end up my go-to cheap tweeter. I still shake my head when I hear it. It's a darn good lil' tweeter.
              Facebook Page - Ocean State Acoustics

              Comment


              • #8
                Re: inexpensive vintage 2-way

                What your guy said?

                Comment


                • #9
                  Re: inexpensive vintage 2-way

                  I dig these. They "look" like they belong in a garage or rec-room (meant as a compliment). They beg to be covered in Jegs, K&N and STP stickers, along with a few beer bottle lables.

                  Comment


                  • #10
                    Re: inexpensive vintage 2-way

                    Thanks everybody for the really kind words, much appreciated and glad you like them! I like that goldwood tweet; it has some rough edges that a good crossover can probably polish off better, but that is nearly every tweeter I guess.. I have always liked the sound of paper cone tweets, especially compared to piezo or mylar..

                    The guy really likes them, and they sound great on his setup. He scored an old Sony ES prologic era receiver at a second hand shop. That thing is pretty stout and seems to have resolved the midrange issue, so perhaps it's partially the fault of my gear that I was thought it was lacking mid attack. They really rock and the sound is huge. The bass is so perfect with all tone and eq controls flat. And I think some Jegs stickers would compliment them well!
                    Projects:

                    transcenD: http://techtalk.parts-express.com/fo...5035-transcend
                    Summits: http://techtalk.parts-express.com/sh...75-The-Summits
                    References: http://techtalk.parts-express.com/sh...-My-References
                    Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

                    Comment


                    • #11
                      Re: inexpensive vintage 2-way

                      Originally posted by mzisserson View Post

                      Edit Edit: What do you think of that GW tweeter? It got quite a bit of play in my "lil' Brits" using a $0.69 buyout woofer. I love it, actually and it may end up my go-to cheap tweeter. I still shake my head when I hear it. It's a darn good lil' tweeter.
                      I just wanted to answer your question better, I didn't have much time when I posted last night, sorry. I like it a lot. When mounted in those guides I threw together (with just lucky guesswork, no calculations or simulations), along with a little damping material in front of the dustcap, the soundfield is really big with almost no localization. It actually has me throwing some ideas around of making some HT speakers laid out like the Klipsch THX mains, with the GT25 in a waveguide vs the horn. I have another pair, along with the Goldwood mids to match, So I may do a WWMT vs the MMT like the Klipsch. I definitely want to and plan to work with it again in other projects. I'd really like to see your lil' brits. I've been searching and will keep looking, but if you have the link, could you post it? Thanks!

                      here's that Klipsch I was talking about:

                      http://www.klipsch.com/kl-650-thx-bookshelf-speaker

                      Again, I appreciate the compliments from everybody alot! Thanks!
                      Projects:

                      transcenD: http://techtalk.parts-express.com/fo...5035-transcend
                      Summits: http://techtalk.parts-express.com/sh...75-The-Summits
                      References: http://techtalk.parts-express.com/sh...-My-References
                      Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

                      Comment

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