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Ultra-budget MT floorstander for about $100 a pair

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  • Ultra-budget MT floorstander for about $100 a pair

    see updated crossover about 10 posts down

    For this project, the name for which has yet to be finalized (there are a couple candidates), the goal was to put together a speaker that would sound good, (especially compared to cheap floorstanders in big box retail stores), be easy to build even for those with limited woodworking skills and minimal tools, and with a price in the $100 range for parts & materials, not including finishing. I also wanted to put together a fairly well-documented build, since this was targeted at folks new to speaker building. For those of you looking for something smaller, i have a PC speaker / HT satellite in the works for about $25 per speaker.... stay tuned.

    Some of these goals were satisfied better than others -- the documentation and cabinet drawings are still in progress, and the price bumped up a little over the ambitious target, but you're probably still less than $110 a pair including MDF, and probably a few more bucks (vinyl laminate and painted baffle) to be completely done.

    Even though the drivers are buyouts, they're expected to be in stock for a while. The 12-ohm nominal woofer (which measures more like a nominal 8-10 ohm) makes this design safe for any amp. I used the Bravox 06BV02S in the prototype because i have about a dozen of them, but the 06VB03B is very similar, but sacrifices a few hz of F3 but uses a smaller box. For those that prefer the gray-cone bravox drivers' appearance, i haven't tested them, but they're probably a drop in replacement. (i'll test it for free if anyone sends one postage paid).

    The tweeter is the Peerless India T25QX01, which has a custom faceplate meant to match up with the Bravox woofers. this means that both drivers are surface mounted, but have rounded frames to reduce diffraction, and a jigsaw is more than sufficient to cut the holes because you won't see any rough edges on either one. the port is a "press-fit" design with a slight lip that will also cover some slightly less than round holes.

    The cabinet is about 1.45 ft^3, tuned to about 45 Hz. (8.5"w x 36"h x 12.5"d. if you use the bravox -03 woofer that's currently in stock, you can shave this to 10.25" deep.) Both model with F3's in the upper 30s, though the -02 woofer that's no longer available shows about 1dB higher below 100 Hz. The lower bass isn't overpowering, but gives a good full-range sound. Since the tweeter is crossed fairly close to its Fs, they're not going to play extremely loud without some increasing distortion, but i haven't noticed any issues at normal levels.

    The in-room measured frequency response is pretty good, with a slight dip around 4,000 hz, and otherwise +/- 2dB. the distortion measurements at 90dB reference level were pretty good too. all of the measurements were done with ARTA at 96kHz, using a pioneer home theater receiver run in stereo mode for the amp, and ART tube MP pre-amp, and a dayton EMM-6 microphone.


    Current pricing list for version 1 crossover:
    (2) $10.25 - Bravox 06BV03B 12-ohm blue poly woofer
    (2) $9.60 - Peerless India T25QX01 1" tweeter
    Bravox 06BV02B
    (2) $6.25 - .90 mH 20ga inductor ($7.25 for 18ga)
    (2) $3.49 - .15 mH 20ga inductor
    (2) $1.25 - 3 ohm dayton 10W resistor
    (4) $1.00 - 4 ohm dayton 10W resistor
    (2) $1.25 - 7 ohm dayton 10W resistor
    (2) $1.25 - 12.5 ohm dayton 10W resistor
    (4) $0.61 - 10ufF nonpolarized electrolytic cap
    (2) $1.34 - 1.0 ufF nonpolarized poly cap
    (4) $0.61 - 12ufF nonpolarized electrolytic cap
    (2) $0.56 - 6.8ufF nonpolarized electrolytic cap
    (2) $3.49 - binding post terminal cup
    (2) $3.15 - 2.5" flared port tube

    version 2 crossover is below, direct link here

    all told, including port, posts, etc, these will run about $90 / pair in parts (maybe $94 if you add screws and some insulated terminals. if you buy everything for 2 sets and get the quantity discount for 4+, you can hit the $80/pair in parts threshold).

    any feedback or constructive criticism appreciated.
    Attached Files
    Last edited by patrickm; 02-09-2012, 09:58 PM. Reason: link to v2 crossover
    TM (RS125/TB25-302), TM RS150S / Vifa BC25SC06, RS150-4 / Vifa ML-TL, 3CR-AL Ultra Budget: Electric Blue TM, TMM, MTM, Dragonflies , Mounties: Mini HT Satellite,sub for minions

  • #2
    Re: Ultra-budget MT floorstander for about $100 a pair

    pretty cool
    " 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


    • #3
      Re: Ultra-budget MT floorstander for about $100 a pair

      Very nice. Do you have the xo drawing? Can you compare these to the tritrix?

      Comment


      • #4
        Re: Ultra-budget MT floorstander for about $100 a pair

        Originally posted by duanebro View Post
        Very nice. Do you have the xo drawing? Can you compare these to the tritrix?
        yup, had to switch computers to post it (also noticed i had the old cap values in the post, so i corrected those now).

        unfortunately, i don't have a tritrix, so i can't make a great comparison. i'd imagine from what i've seen the tritrix gets a decent amount louder, and they appear to have a little flatter frequency response than these. since the surface area on the tritrix's two drivers is a little larger, that and the TL may give it a little better extension. and mine doesn't come with a fancy knock-down cnc'd cabinet kit

        also, here are larger versions of the distortion charts... PNG look better, but the size was really limited. graph is the same, just scales up better in this one.
        Attached Files
        TM (RS125/TB25-302), TM RS150S / Vifa BC25SC06, RS150-4 / Vifa ML-TL, 3CR-AL Ultra Budget: Electric Blue TM, TMM, MTM, Dragonflies , Mounties: Mini HT Satellite,sub for minions

        Comment


        • #5
          Re: Ultra-budget MT floorstander for about $100 a pair

          Patrick, you are a man after my own heart

          Those little aluminum tweeters are very nice. I bought a bunch of the faceplate-less ones last year, still have three of them.
          Don't listen to me - I have not sold any $150,000 speakers.

          Comment


          • #6
            Re: Ultra-budget MT floorstander for about $100 a pair

            I only have one complaint.

            The 2 C1 values (1uF/6.8uF) in the woofer portion allow the transmission of ultrasonics to be shorted to ground, possibly causing amplifier instability. I would recommend a 4 ohm resistor in series with the 1uF value, or a 2 ohm minimum in series with the 6.8uF value to avoid that potential issue.

            It's otherwise very well thought out and looks like a good build for a first-timer to attempt.
            Thanks for sharing!
            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


            • #7
              Re: Ultra-budget MT floorstander for about $100 a pair

              Originally posted by Wolf View Post
              I only have one complaint.

              The 2 C1 values (1uF/6.8uF) in the woofer portion allow the transmission of ultrasonics to be shorted to ground, possibly causing amplifier instability. I would recommend a 4 ohm resistor in series with the 1uF value, or a 2 ohm minimum in series with the 6.8uF value to avoid that potential issue.
              complaint appreciated, and changes made. the 1.0 uF was a late add during measurements, and i'd run an impedance sweep but hadn't thought about stuff outside the audio range.
              TM (RS125/TB25-302), TM RS150S / Vifa BC25SC06, RS150-4 / Vifa ML-TL, 3CR-AL Ultra Budget: Electric Blue TM, TMM, MTM, Dragonflies , Mounties: Mini HT Satellite,sub for minions

              Comment


              • #8
                Re: Ultra-budget MT floorstander for about $100 a pair

                Originally posted by johnnyrichards View Post
                Patrick, you are a man after my own heart

                Those little aluminum tweeters are very nice. I bought a bunch of the faceplate-less ones last year, still have three of them.
                ha, thanks. they're actually pretty good. i'm also glad my blue woofers didn't have the cone sag problem some of the other batches did. anyhow, speaking of our projects to give something back to the community through some super-cheap entry-level designs, watch out for this little guy, he's up next....
                Attached Files
                TM (RS125/TB25-302), TM RS150S / Vifa BC25SC06, RS150-4 / Vifa ML-TL, 3CR-AL Ultra Budget: Electric Blue TM, TMM, MTM, Dragonflies , Mounties: Mini HT Satellite,sub for minions

                Comment


                • #9
                  Re: Ultra-budget MT floorstander for about $100 a pair

                  Another excellent tweeter choice!

                  I have a three way coming up using two these, one of these, and one of these. Medium sized floorstander with full baffle step. Won't go particularly low, but will be capable of some decent output.
                  Don't listen to me - I have not sold any $150,000 speakers.

                  Comment


                  • #10
                    Re: Ultra-budget MT floorstander for about $100 a pair

                    version 2. after listening to them for a week and thinking they sounded a little forward compared to my primary set of speakers, i decided to take a hack at a more relaxed presentation, and one that actually gets a tad more sensitivity (to me, this suggests i should keep optimizing the original design). i went with a simplified crossover that cuts the part count, and i think overall i like this one better. it measures slightly better in-room too, but not everyone that builds one will have the same room dimensions i do.

                    the parallel resistor can be adjusted from 2.4 up through 6 ohms if you need to make the tweeter a little brighter or softer.
                    Attached Files
                    TM (RS125/TB25-302), TM RS150S / Vifa BC25SC06, RS150-4 / Vifa ML-TL, 3CR-AL Ultra Budget: Electric Blue TM, TMM, MTM, Dragonflies , Mounties: Mini HT Satellite,sub for minions

                    Comment


                    • #11
                      Re: Ultra-budget MT floorstander for about $100 a pair

                      Originally posted by patrickm View Post
                      ha, thanks. they're actually pretty good. i'm also glad my blue woofers didn't have the cone sag problem some of the other batches did. anyhow, speaking of our projects to give something back to the community through some super-cheap entry-level designs, watch out for this little guy, he's up next....
                      oooooh...

                      I've always wanted to try a speaker with waveguide tweeters.

                      From what I gather, it's a good thing, allowing the tweeter to be crossed lower, among other benefits... why isn't it done more often?

                      Comment


                      • #12
                        Re: Ultra-budget MT floorstander for about $100 a pair

                        Originally posted by lunchmoney View Post
                        oooooh...

                        I've always wanted to try a speaker with waveguide tweeters.

                        From what I gather, it's a good thing, allowing the tweeter to be crossed lower, among other benefits... why isn't it done more often?
                        I think the reasons are two-fold: one is that there is an association with WG and honky sound, and two: cost plus complexity.

                        Both reasons are no longer valid, not really. This day and age of cheap measurement tools and wide spread availability of woodworking tools has made addressing the difficulties much easier.

                        I have used the larger brother of the WG tweeter in the micro monitor above, and I really liked how it sounded.
                        Don't listen to me - I have not sold any $150,000 speakers.

                        Comment


                        • #13
                          Re: Ultra-budget MT floorstander for about $100 a pair

                          pair #1 is now basically finished up. going through the listening test, but sounding pretty good so far. these are just krylon'd MDF baffles and the PE cherry vinyl. (the color actually looks deeper in person). overall i'm pretty happy with this project. I think the crossover should also work in a bookshelf version, maybe 11-12" tall, tuned to about 50 hz. may build a matching pair just to test.
                          Attached Files
                          TM (RS125/TB25-302), TM RS150S / Vifa BC25SC06, RS150-4 / Vifa ML-TL, 3CR-AL Ultra Budget: Electric Blue TM, TMM, MTM, Dragonflies , Mounties: Mini HT Satellite,sub for minions

                          Comment


                          • #14
                            Re: Ultra-budget MT floorstander for about $100 a pair

                            Nice work - I'm sure they'll live long and prosper.

                            (snicker)

                            But really, great work!

                            Marty

                            Comment


                            • #15
                              Re: Ultra-budget MT floorstander for about $100 a pair

                              Those are pretty sharp looking! For reference, here is the FR plot of the Bravox 6.5" silver cones taken on about a 9" x 12" baffle with no roundovers:





                              Probably quite close to a drop in, although the woofer frame is different, cosmetically. Not enough to make much of an impact I imagine.
                              Don't listen to me - I have not sold any $150,000 speakers.

                              Comment

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