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Budget Dayton 3way project

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  • Budget Dayton 3way project

    Thinking of next year's MWAF, I started planning this around the DC28F-8, PA165-8 and SD270a-88 as a <$100/each 3way that could reach ~105db with an F3 around 40hz....then realized Dayton's 15-20% price increase this year puts that combination about $0.50 over the mark. Sooo close! :(

    Although the ND25FW-4 looks like a really good option (so do the PC105 and PA130-8). I kind of threw my hands up and decided I can lower all three to the TD20F-4, PC105-4 and SD215a-88....cutting driver costs nearly in half (and reusing drivers I already own) and shrinking the required cabinet size.
    These might still be able to reach up to ~102db, not a terrible ways short of the original plan.

    I'm leaning toward a 1.5ft-cu cabinet, tuned a little under 40hz while keeping the port short enough to push resonance above 1100hz where the woofer's response should be -25-30db down.

    I'm really curious if a 200-300hz XO point from sub-to-mid is low enough to allow the sub to be side-mounted instead of forward-facing with the rest of the drivers?
    I'd love to be able to make these 6-8inches wide instead of 10inches wide if possible.
    Is that XO point too high to allow side-mounting with good results?
    My first 2way build

  • #2
    A few comments. Maybe MWAF gets a 20% limit increase? Under $200 doesn't mean all Dayton. There are better tweeters for the price of the DC28F. GRS can work as mids. Pair of DC160-8 will go low. Side mounted woofers I'd recommend below 200 Hz. Your Mid will need to get bigger/ have multiples to go to 200 with overlap.
    John H

    Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

    Comment


    • LOUT
      LOUT commented
      Editing a comment
      A ~20% limit increase does seem kind of likely. I'm guessing a lot of driver prices have shot up between price increases for supply/shipping and the US dollar's worth dropping.
      I know the <$200 and Dayton categories are two different classes, but I don't have the gear nor ambition to measure at home (I've heard the outdoor ladder technique is basically required if you want resolution higher than ~1/3octave below 2khz from gated measurements)...so I rely on the frd files despite their flaws, and I like the thrifty comfort of staying within the lowest price class even when it's pretty arbitrary.

      I think a single SD215a-88 can keep up with a pair of DC160-8 down to ~40hz F3 while allowing a smaller enclosure and lower price. The pair of DC160-8 could work for a 2.5way, but the SD215+PC105 combo is still a little cheaper and won't have the midwoofer playing nearly as deep.
      Pair of DC160 would make a slimmer cabinet easier though...no need to worry about side-mount.

      200hz sounds like a good target then. I'll probably mess around to see what I can do with the PC105 because I did have it crossing a little below 200hz while climbing to about 3/4 xmax (about 1.5mm), but that was an earlier and rougher XO. Might be able to get the lows behaving similarly without screwing up the mid-XO section now that I know 200hz is something worth persuing.

  • #3
    I tested the PC105-8 a while back when I was starting to plan a similar effort.
    I would have moved forward with it, but was unable to tame its breakup with as few parts as I wanted at the time. (I was going for 2nd order slopes or Duelund transfer functions if you will.)
    Little did I know that you could probably “tank” it with a small cap just like on a woofer.

    In my opinion, it performs incredibly well for the money. Punches way above its weight. HD is pretty darn good and response is smooth. By the way the FR breakup does not manifest as HD either.

    good luck with whatever you go with!
    Greg

    Comment


    • LOUT
      LOUT commented
      Editing a comment
      I practically never see the PC105 used (outside of Wolf's BarGain soundbar) which makes me worry that it has some terrible flaws where folks (with better ears than I have) are avoiding it, so it's great to hear it's capable of working very well. Admittedly my current 2ways using them are pushing them well out of their intended range down low, but I sit fairly close and they still seem to handle things "gracefully" (their bass can get growly when pushed, but it's not unpleasant to me).
      A 3way should avoid my previous mistakes though.

      I just started to assume ALL instances of frequency spikes/breakup included a lot of HD. That's interesting to learn it doesn't necessarily have to.
      In your measurements, do you remember if it had any issues with "ringing" at certain frequencies? I'm about 95% certain what I'm hearing is a cabinet or port resonance, but it doesn't hurt to ask.

  • #4
    I believe this is the driver that someone cut some small slits in the cone and was able to drastically reduce the breakup and even HD.

    Comment


    • LOUT
      LOUT commented
      Editing a comment
      I think I remember seeing a thread about that using one of the SB drivers. It was a smooth-cone driver, not woven or anything super textured.
      The PC105 (and rest of the PC lineup) have a somewhat glossy, tightly texured cone rather than smooth (I really like how their cones look, but that's subjective).

  • #5
    I don't think anyone slit the PC105, least not to my knowledge. The main offender was the PM180, and then the NSB buyouts.

    There's no reason to slit the woven cones as the wave breaking is already accomplished.

    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


    • #6
      Here’s my HD measurements @96dB and 12”/30cm:

      Click image for larger version

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      It beat out the known performer and beloved TG9 in HD in my testing which puts it in darn good company. You have to spend a good bit of money to get a smooth response and low consistent HD across a wide bandwidth better than that guy. You’re getting dangerously close to SB15MFC30 territory. I’m not saying it’s as good as the SB driver, but it’s got low HD.

      You can also see that although the HD2 peak at 4.5kHz seems to correspond to the FR breakup, there is no corresponding HD3 peak at 3kHz.

      I don’t see why this driver isn’t used more. I’m a big fan.

      Comment


      • LOUT
        LOUT commented
        Editing a comment
        Thanks for posting the measurement. I remembered seeing it earlier (I think in your thread comparing different woofers with a giant baffle for halfspace measurements), but this means I don't have to dig through the search feature.
        Now I can pretend the reason I love the pc105 is because it's a deceptively good driver and ignore the real reason that I'm simply not a very discerning listener.

    • #7
      Originally posted by Wolf View Post
      I don't think anyone slit the PC105, least not to my knowledge. The main offender was the PM180, and then the NSB buyouts.

      There's no reason to slit the woven cones as the wave breaking is already accomplished.

      Wolf
      Yes my bad I had the drivers confused.

      Comment


      • #8
        Finally got around to wiring up (rats'-nesting?) an XO for one of these. The box isn't the final shape or anything, but the front baffle isn't miles off from the dimensions I'm hoping for.
        I was afraid all of the higher-mH inductors I ordered a couple months ago were backordered and trapped together with some more stubborn backorders I'm still waiting for, but a couple of 4mH made it through along with some higher-uF caps....unlike the DMA45's which seem to be stuck in limbo. :(

        I understand proper gated, outdoor measurements would be better, but I can at least simulate what this might reach. This SIM includes some rough baffle/diffraction modelling as well as rough driver Y and Z offsets. The woofer's ported low-end extension isn't merged into these though.

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        The PowerDissipation and PortTuning6Pack sims are set around 12.5v (around 35-40watts @ 4ohm I think).
        The port tuning will probably end up higher as I get closer to the final version (shorter port length to push resonance up over 1khz), but this should more accurately show what it's doing right now. ​​

        I haven't heard them doing anything nasty yet, but I also just got them together and am probably a little too excited to be critical.
        My first 2way build

        Comment


        • #9
          You got the fever...
          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


          • #10
            I'm curious about why you'd put the 1.1 ohm resistor in the woofer's path. I'd think it would have to be a fairly high wattage resistor.
            It is estimated that one percent of the general population are psychopaths - New Criminologist: Understanding Psychopaths

            Comment


            • #11
              Originally posted by mattk View Post
              I'm curious about why you'd put the 1.1 ohm resistor in the woofer's path. I'd think it would have to be a fairly high wattage resistor.
              The resistance shown in-line with each inductor is the combined DCR/resistance of the inductors I'm using. Because I don't have a 5mH coil I instead resorted to using a couple 0.5mH and a single 4mH altogether in series (while trying to keep them a decent distance from each other)...which unfortunately increases the overall DCR by about 0.6ohm more than a single 5mH solidcore would likely have.

              The only real resistors being used are the 2ohm fellows on the midwoofer and tweeter....which I just realized could probably be simplified down to a single one shared between those two drivers. Neat.

              EDIT: Interesting, it looks like sharing a single 2ohm resistor and splitting afterward to the tweeter and midwoofer XO sections gives a slightly steeper roll-off for both the mid-LP and the tweet-HP, while using two seperate 2ohm resistors (one for the tweeter and one for the midwoofer) gives a gentler roll-off...as well as slightly flatter horizontal dispersion (but slightly less flat vertical/downward dispersion).
              This is the kind of circuit/XO thing that my brain doesn't find quite as intuitive (at least not enough to remember off-hand what the difference will naturally be), but I'll try to keep it in mind nonetheless.
              Last edited by LOUT; 08-19-2021, 05:05 AM.
              My first 2way build

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              • #12
                I picked up some 1/2" plywood and started cutting. It's surprisingly poor quality (never saw plywood warp that fast before) which is kind of a bummer, but the hardest cuts seemed to go well so I have some hope of it turning out alright. The amount of glue/filler and chips means it'll probably need to be painted instead of stained (the previous time I bought this stuff it was nice enough to stain) but I need to get better at smoothing and painting anyway. This counts as practice.

                Final outside dimensions should be 8.5"-wide, 35" tall and 15.5" deep if I don't mess up the last few cuts. This should leave around 2ft-cu for the woofer which lets a stubby <5"-long port reach ~30hz.

                I realized the information on the Dayton TD20 specsheet mis-lists the SD at 31.4cm when it should probably be closer to 3.8cm. Even Dayton's own website lists it this way, so it's not just a PE website typo. This made me realize the tweeter would obviously end up passing 0.1mm earlier than originally planned (I think its XMAX is ~0.2mm, but figured better safe than sorry), so I might tweak the HP to cross a little higher. I found what looks to be a good spot where it should handle the box getting ~40watts without pushing the tweeter beyond 0.1mm, but I'm not sure how I like the potential squiggly lines changes.
                I'll likely try different things after they're put together for real (instead of their current temporary boxes), but I doubt I'll be able to hear much difference if any....unless one of the XO tweaks does something pretty obvious and weird.
                My first 2way build

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                • #13
                  You could look at the DX20BF00-04 if you run into limitations with the TD20. The DX20 is about the same size (1 mm larger frame) and has an Fs that is 1/2 of the TD20. It has an Xmax of 0.2 mm and an Sd of 4.9 cm2. I have used it and consider it a great budget 3/4" tweeter at $5 more than the TD20. Personally I wouldn't xover it any lower than 3 KHz LR4 and maybe 3.5 KHz LR2. YMMV.
                  "Everything is nothing without a high sound quality." (Sure Electronics)

                  Comment


                  • LOUT
                    LOUT commented
                    Editing a comment
                    Thanks for the recommendation. I should've probably mentioned that I'm still only raising the XO point to about 2200hz compared to the current one that should be just a hair under 2000hz, and the slope is between 2nd and 3rd order I think (around 15-18db/oct).
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