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The Mounties - 5.0 on the cheap

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  • The Mounties - 5.0 on the cheap

    As if there weren't enough micro-monitors already, I'll add mine to the mix. The goals were straightforward: Small, cheap, light enough to be wall-mountable anywhere, wood matched to the rest of the room, and competitive or better SQ-wise than entry/mid-level HTIB systems.

    The cabinets are pretty simple in design, but execution is a little tougher. They're 3/4" pine, 8"h x 5"w x 6"d, ported to 105 hz with a 1"d x 2.75" port. It's tough to fit the crossover and retrieve it, and it generally went through the woofer hole and was hot-glued to the bottom of the cabinet (no boards). based on actual woofer measurements (most of mine had Fs near 98 hz, rather than the advertized 111hz), the modeled F3 is ~ 95 hz. i think they'd be ok crossing at 100 hz to a sub, 125-150 if you really need it loud.

    The peerless india woofer needs a shallow lip routed around the top edge of the mounting hole, but it's almost the same diameter as the frame, so it's easy to leave that showing. it also doesn't have great venting behind the cone, so it's required to route out some material on the backside of the baffle if 3/4" is used, and probably some if 1/2" is too.

    The nuance tweeter has 3 screw holes around the edge, but is almost .625" deep itself, so there's little material for the screw to grab. on one baffle, i set the depth for the router a tenth too far, and went all the way through. i learned that strategically glued thin scraps behind these screw holes made a lot of sense.

    the wood came from one or two 6" wide, 8-foot pine boards from home depot that were maybe $7 each. this is a little softer than what i usually use, but allowed them to have a nicer, more consistent grain pattern. life is full of tradeoffs. stain is minwax walnut oil-based, with some wipe-on gloss poly.

    the crossover was 2nd order electrical on both woofer and tweeter with an L-pad. values on the L-pad are pretty flexible, i posted the best combo i found overall, but one or two of my 7 tweeters were a dB or so louder/quieter, so getting a few resistors in the 2.4-4 ohm range will allow for quick adjustments. i usually went with 2.4 and didn't go above 2.7 on the series resistor, but used 2.7, 3, or 4 for testing on the shunt resistor. phase tracking is not perfect, but the 3rd order electrical on the tweeter i also experimented with modeled a little better, but lacked some air in the top end. since these are for HT, i figured that's more important. since these are expected to be on/near wall, and to keep costs down, there's no BSC to speak of. with the waveguide tweeters, they sound pretty good off-axis, which is great for HT speakers placed in non-optimal locations.

    i like the midrange on the peerless india woofer. once it has some good airflow, it sounds pretty smooth. it was a bit choked and distorted easily on a test baffle previously. these are 4-ohm speakers, but they're pretty efficient (woofer is 88.5 dB), so most amps shouldn't struggle with the load, it's only pushing a couple of watts at the most.

    Total cost for parts for a set of 5 was $111, including screws, port tubes, and terminal cups. The 5W 5% wire-wound resistors are probably fine for this project, given the low power levels, and will save some money and space, but i had the dayton's on hand.

    The name came from the wall-mounting requirement.... they were almost called the "microns" but i'm gonna save that for another day.

    so the overall verdict is that it met or exceeded initial expectations, and the value is good, but the woodworking is a little trickier than first thought. it can be frustrating to stuff things into the cabinet and do all the router work, so beginners, be advised.
    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

  • #2
    Re: The Mounties - 5.0 on the cheap

    and a few build shots, highlighting the baffle recesses:
    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


    • #3
      Re: The Mounties - 5.0 on the cheap

      Those look cool , very high WAF!

      Comment


      • #4
        Re: The Mounties - 5.0 on the cheap

        Originally posted by patrickm View Post
        it can be frustrating to stuff things into the cabinet and do all the router work, so beginners, be advised.
        That's the challenge of the small-box design! :D

        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


        • #5
          Re: The Mounties - 5.0 on the cheap

          Yep, mounting small woofers can be a PITA. Project looks great, and I have five of those woofers sitting around I may have to do something with now. Good job Patrick!
          Don't listen to me - I have not sold any $150,000 speakers.

          Comment


          • #6
            Re: The Mounties - 5.0 on the cheap

            Originally posted by Wolf View Post
            That's the challenge of the small-box design! :D
            and making crossovers on boards....
            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


            • #7
              Re: The Mounties - 5.0 on the cheap

              I bought six of these tweeters. They would have been great if they had matched Zaph's test results, but they were wildly variable:

              http://techtalk.parts-express.com/sh...d.php?t=223838

              Maybe yours don't have this problem, but I would test them all to be sure, if you can.

              John

              Comment


              • #8
                Re: The Mounties - 5.0 on the cheap

                yeah, i remember that thread. i bought about 10 planning to use either 5 or 7, and tested 3-4 before my computer went down a few weeks ago. still haven't gotten everything back up and running for measurements, but the 3 i had mostly had 1-2 dB level variations that i compensated for in the L-pad, and didn't seem to have the same spread yours did. thanks for the reminder, though. did yours ever change after use?

                EDIT: also, re-reading that thread, i think you got the 4 3/4" waveguide tweeters, i got the 2 3/4". i'm sure the tweeters are the same, but not sure about the comparative age or storage quality since initial production -- i know some of the blue bravox woofers had cone sag problems, and others were just fine.
                Last edited by patrickm; 06-18-2011, 10:53 PM.
                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: The Mounties - 5.0 on the cheap

                  I've just started work on these and I need some help. I've only built two and already made mistakes with the enclosure, and now I look at the xover diagram and the coils are different to the cart and they distort easily with my lepai. The enclosures are 8H x 5W x 6D built from 5/8" plywood.Is there something I've missed and which coils are correct? My Zaph's B3S seem to be handling more power, how is that possible?

                  Comment


                  • #10
                    Re: The Mounties - 5.0 on the cheap

                    I really like these. The boxes look great, and the price is right. Very cool!


                    Mark
                    You go your way, I'll go mine. I don't care if we get there on time.

                    ~Pink Floyd

                    Comment


                    • #11
                      Re: The Mounties - 5.0 on the cheap

                      Originally posted by Palos View Post
                      I've just started work on these and I need some help. I've only built two and already made mistakes with the enclosure, and now I look at the xover diagram and the coils are different to the cart and they distort easily with my lepai. The enclosures are 8H x 5W x 6D built from 5/8" plywood.Is there something I've missed and which coils are correct? My Zaph's B3S seem to be handling more power, how is that possible?
                      Hi - the coils in the cart are a little oversized because i didn't see a .12 mH at PE, and tried both .60 mH and .55mH as I refined the design on the woofer section. For the .12, you need to unwind a few turns from the .15 mH. (I have a meter, and didn't count how many). either way, using .12 / .55 or .15 / .60 should not cause the high distortion.

                      i have some zaph B3S's here, and tried those with a lepai, and both got reasonably loud before distortion sets in. For the 5.0, i had been using an old pioneer HT receiver, and turned it up pretty far. first, i'm assuming you have a clean signal to the lepai and the input isn't over-driven and that you don't have the bass knob turned up because the B3S's work ok.

                      the first thing to make sure is that you removed some of the material on the inside of the baffle aroudn the woofer opening. you want to leave about 1/4" just around the woofer so it can breathe. that's the most likely cause of distortion.

                      the woofers do require some break-in time - if this is the first you've powered the up, give it some time, or gently flex the cone in and out with your fingers (be careful not to go too far).

                      if it's not any of those problems, and you hook up the tweeter and woofer individually, can you tell which one the distortion is coming from? alternatively, if you post a picture of your crossover, i'd be happy to take a look and help troubleshoot.
                      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


                      • #12
                        Re: The Mounties - 5.0 on the cheap

                        Originally posted by Mark65 View Post
                        I really like these. The boxes look great, and the price is right. Very cool!
                        thanks, man, especially from someone with an equally tiny two-way. these actually looked a bit better in person than the photo (a little darker, the flash kind of cut through the stain or something). i've been tempted to pick up some of those aura's at madisound before they run out to give it a try, but i've been trying to thin the herd of drivers here.
                        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


                        • #13
                          Re: The Mounties - 5.0 on the cheap

                          Thanks for the response. I bought a lcr a cheap with this order so I'll measure and then unwind and re measure to see how accurate it. As for my MISTAKES, I didn't chamfer the inner baffle and I put on of the terminal cups behind the tweeter so I may have to add a baffle or redo the boxes. They have had about 4-5hrs of listening time. How long was their break in period and how is the bass response compared to your B3S, mine is hardly there. The woofer is distorting and I'll post pics of the xo, for now the components are just twisted together and lead through the port.

                          Comment


                          • #14
                            Re: The Mounties - 5.0 on the cheap

                            Thanks for the response. I bought a lcr a cheap with this order so I'll measure and then unwind and re measure to see how accurate it. As for my MISTAKES, I didn't chamfer the inner baffle and I put on of the terminal cups behind the tweeter so I may have to add a baffle or redo the boxes. They have had about 4-5hrs of listening time. How long was their break in period and how is the bass response compared to your B3S, mine is hardly there. The woofer is distorting and I'll post pics of the xo, for now the components are just twisted together and lead through the port.
                            not sure i'd recommend someone else do this, but i have used a rabbeting bit before to remove material through a baffle before. (i've also chopped/chisled off baffles and replaced them too, that's the safer way to go). but i think that's the main problem, the low power handling, lack of bass, etc. all point to the same cause, that the woofer is getting choked. the venting in the back of it isn't very good, so it's more critical than usual to give it some air.

                            as for break-in time, i flexed the cones, and most of the changes seemed to be within the first couple hours.

                            the bass on mine were comparable to, if not better than, the sealed B3S. i think in the final setup the sub crossover for them was at 80 or 100 hz. that high-pass definitely helps, but it didn't have to be 150-200.
                            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


                            • #15
                              Re: The Mounties - 5.0 on the cheap

                              I did end up coming up with a full range design for the PoI woofer, if'n anyone is interested. I was able to use all buyout caps from Madisound, but the coils drove the cost up farther than the driver is worth (IMHO). In addition, the driver cutout was not chamfered, and the baffle was not rounded over, I got lazy.
                              Don't listen to me - I have not sold any $150,000 speakers.

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