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Peerless by Tymphany STW-350F-188PR01-04 in a Passive Radiator Set-up

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  • #16
    When I model PRs, granted I use WinIsd, I put in the native parameters of the PR, Fs, Sd, Xmech, and Qms and let it calculate anything extra. I add weight then to get the desired tuning.

    Before I do any of that though I see what an optimum vented enclosure looks like and what a near ideal Fb is. That is generally what I model to then with the PR design.

    you can probably do the same in the software you are using.

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    • #17
      Originally posted by STIchris722 View Post

      Per PE's add:
      "With an Xmax of 10.4 mm this driver might not seem all that impressive. However, Xmax is just a physical measurement and not actually the limit of linear excursion (Xmax = (Voice Coil Length - Magnetic Gap Height) / 2). The STW-350F has a remarkably long 36 mm magnetic gap with a 57 mm long voice coil. Thanks to such extreme dimensions and a well controlled magnetic field, this driver is capable of 45.5 mm of excursion before any major loss in motor strength (Bl). In other words, this driver is capable of 90 mm (3.5") peak to peak excursion while still producing low distortion output."

      I understand the math for Xmax, but the 45.5mm is not derived from any numbers I can make sense of. I am probably way off here, but I thought anything passed your forward linear excursion (Xmax) that the coil winding would be above the magnetic gap. If someone could shed some light on this I would greatly appreciate it. As it stands now, this excerpt from the PE add completely confuses me on what Xmax ever meant and is making me question whether the figure is important or not. Is the Xmax 45.5mm or 10.4mm? If it is 45.5mm then that totally changes the passive radiator calculations doesn't it?
      Xmax is the total stroke in one direction with the coil completely within the magnetic gap. The cone does not stop at that point though - all that happens is less of the coil is within the gap. Traditionally, the force developed by the coil will be reduced because less of it is in the gap, but there will still be force. How they can claim that there is no major loss in motor strength is interesting.

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      • #18
        Originally posted by Dukk View Post

        Xmax is the total stroke in one direction with the coil completely within the magnetic gap. The cone does not stop at that point though - all that happens is less of the coil is within the gap. Traditionally, the force developed by the coil will be reduced because less of it is in the gap, but there will still be force. How they can claim that there is no major loss in motor strength is interesting.
        Something to do with their internal motor structure ...
        http://techtalk.parts-express.com/fo...khanspires-but
        http://techtalk.parts-express.com/fo...pico-neo-build
        http://techtalk.parts-express.com/fo...ensation-build

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        • #19
          I've been fiddling with this same driver with PR's quite a bit lately. I'm by no means an expert concerning the driver or PR's but my conclusions have been thus:

          There are VERY FEW passive radiators that can handle the weight and excursion required to tune the driver low enough and loud enough to take advantage of the driver's potential.

          My goal is 20 hz flat at 115db, 17hz f3, reasonable sized box (aimed for 4 cu ft, but might go up to 5). That my not be your goal, and that's fine. But in order to do that, the only suitable PR's I've found are the CSS APR and Earthquate SLAPS. BOTH require multiples to accept any power levels above a plate amp (like the power from a Crown XLS1500 or XLS2000 that I'm currently using). I have both sitting in the basement ready to try but no time yet to build an enclosure.

          The real problem I've found is that a single PR isn't sufficient, neither is a pair of PR's. Instead, a quartet of 12" PR's is needed. But when you add more PR's, you also have to add more weight to each one to keep the tuning low. If you step up to a 15" or 18" PR (or pair of PR's, as is required in my case) they simply aren't designed to handle that kind of weight. So you must compromise and accept a higher tuning frequency, lower power handling and output, or risk destroying the PR's. The APR12 needs between 1000 and 1100 grams EACH to tune infrasonic.

          NOTE: it is my understanding that the weight chart listed for the Dayton's PR's is the TOTAL moving mass, NOT THE ADDED MASS. Meaning, the moving mass of the diaphram and associated parts is 400 grams without any added weight. The 925 grams is after adding all seven disks - the weight of added mass totaling only 525 grams. This is the weight that should be entered in to WinISD under Added Mass NOT 925 grams. Look closely at the product description and hopefully I am understanding that correctly. One of the forum moderators on here even noted that they have never added more than the listed mass via the included disks to a Dayton PR so they aren't sure if it could handle they type of weight that the CSS APR12 can.

          I really like this driver. I have one sitting in the basement waiting to replace an HT18 that is going to a friend. I figure it needs to outperform the HT18 in order for it to be worthwhile. I've run at least 100 sims with the driver so far - sealed, vented, LLT, PR with at least 30 different PR's or PR configurations. I guess you need to decide how loud and low you want it to play. Like I said, higher tuning and less power make the Dayton PR's a viable option. But why limit the driver? So far, the honest best configuration I've found is vented 4.5 cubes with 2 stoopid long ports. Good for 116 db on 1550 watts with vaguely acceptable port velocities. Or a quartet of CSS APR12's maxed out which still yields a sub-20hz F1. Sorry for the rant. I suspect I will be building several enclosures for this driver for fun but wanted to share a bit of what I've observed. It would be fun to see what the Dayton PR's can support before exploding...

          Comment


          • #20
            Originally posted by Blenton View Post
            I've been fiddling with this same driver with PR's quite a bit lately. I'm by no means an expert concerning the driver or PR's but my conclusions have been thus:

            There are VERY FEW passive radiators that can handle the weight and excursion required to tune the driver low enough and loud enough to take advantage of the driver's potential.

            My goal is 20 hz flat at 115db, 17hz f3, reasonable sized box (aimed for 4 cu ft, but might go up to 5). That my not be your goal, and that's fine. But in order to do that, the only suitable PR's I've found are the CSS APR and Earthquate SLAPS. BOTH require multiples to accept any power levels above a plate amp (like the power from a Crown XLS1500 or XLS2000 that I'm currently using). I have both sitting in the basement ready to try but no time yet to build an enclosure.

            The real problem I've found is that a single PR isn't sufficient, neither is a pair of PR's. Instead, a quartet of 12" PR's is needed. But when you add more PR's, you also have to add more weight to each one to keep the tuning low. If you step up to a 15" or 18" PR (or pair of PR's, as is required in my case) they simply aren't designed to handle that kind of weight. So you must compromise and accept a higher tuning frequency, lower power handling and output, or risk destroying the PR's. The APR12 needs between 1000 and 1100 grams EACH to tune infrasonic.
            Your Goal is basically on point with mine. I was going to use an Ashly KLR4000 to power it (4000W RMS @4ohms bridged Mono). Riddle me this....What happens if you use a more dense mass on the PR instead of the stamped pot metal washers? I was thinking about some tungsten or lead that could be threaded on. How does that change things?

            When you model this, what are you inputting for Xmax on the Peerless?
            "I don't know everything and do not claim to. I continue to learn and that is what makes me human."

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            • #21
              Originally posted by Dukk View Post

              Xmax is the total stroke in one direction with the coil completely within the magnetic gap. The cone does not stop at that point though - all that happens is less of the coil is within the gap. Traditionally, the force developed by the coil will be reduced because less of it is in the gap, but there will still be force. How they can claim that there is no major loss in motor strength is interesting.
              This has been beat to death on this and other forums. A little bit of marketing but a lot of engineering has been put in to this driver to make it work as it does - big driver, small box, low tuning, gobs of power handling, insane amounts of excursion. I can't pretend to know the intricacies of loudspeaker motor design, but I think the key is "no MAJOR loss" in motor strength. bcodemz explained some of the advantages of the motor design with that ginourmous coild and what it will get you in real life. I mean, it would seem to reason that there is so much wire on an almost 8" coil that even if half of it left the gap, you would still have more wire in the gap than most any other driver with a 4" or small voice coil!

              If everybody and their dog hadn't run poor George Bullimore gbullimore off every other forum for bestowing an amazing driver on the DIY community, only to have everyone pough pough on a single parameter that is very poorly defined by ANY manufacturer (coil vs gap / 2, coil vs gap /2 * 15%, coil vs gap /2 *30%, klippeled 10 %, klippeled 15%, yadayadayada) then argue with the man who designed it, positing that they (the DIY community members) know sooooo much more than the Tymphany designers when it comes designing a good driver instead of, oh, I dunno, asking productive questions.. Like why they rated Xmax at 10.2 mm or what they mean by "no major loss in motor strength" and what this driver excels at. Instead, it was the usually inflammatory defamation of a driver being scrutinized on paper while simply dismissing the few with first hand experience or any knowledge on the matter. Ugh. Sorry. Bigger rant. Just wish I was around when George was frequenting the forum - would have loved to pick his brain before everyone started lobbing flaming brown paper bags of excrement at his front door.

              So, I guess that means I'm doubling down on the STW-350F. Ha! Adding another one to the cart this weekend...

              And, if you feel that those comments were in any way berating or derogatory and aimed at you - they were not. I'm not lobbing flaming paper at anyone here. I don't feel it is productive to point fingers and start a flaming war so please don't misunderstand my intentions or words. Just wanted to set up my straw man that was made from other peoples' words and burn the thing to the ground.

              Comment


              • #22
                Originally posted by STIchris722 View Post

                Your Goal is basically on point with mine. I was going to use an Ashly KLR4000 to power it (4000W RMS @4ohms bridged Mono). Riddle me this....What happens if you use a more dense mass on the PR instead of the stamped pot metal washers? I was thinking about some tungsten or lead that could be threaded on. How does that change things?

                When you model this, what are you inputting for Xmax on the Peerless?
                Cool. Glad to hear that. I didn't want to put words in your mouth or assume you wanted the same thing just because I did. You know, the old "well, I'M doing this with this driver, so YOU should do the same thing..." Haha.

                The density of the weights is irrelevant; it's the total mass that matters. Well, I mean, to a point. If you stacked styrofoam on it to get your desired mass, well, that would just be silly. But 500 grams of tungsten would do the same thing as 500 grams of steel. Adding more mass shifts the tuning down, but also increases the PR excursion. So you usually run out of PR excursion tuned low way before driver excursion or power handling (the two real limiting factors for a subwoofer). So you add another PR, but now your resonate system has twice as much surface are so you have to add more weight to each PR to keep the tuning low. So you up the power until you run out of excursion or can no longer hang more weight on the PR without it sagging or un-centering itself. And thus goes the cycle.

                It really is quite analogous to a standard port: small diameter ports (PR diameter) can easily be tuned low using a shorter port length (smaller added mass), but the tradeoff is higher air speed. In order to decrease air speed, you need to increase the port diameter which, in turn, increases the length. Add a second port of equal size (PR), and now you have to lengthen both ports (add more mass to each PR) to keep the tuning same tuning.

                I entered 10.4mm in the TS parameters, but see my "usable" xmax as ~20mm. From the hundreds of pages of forum posts by fodder tossers that I've waded through concerning the STW-350F, this appears to be a more acceptable Xmax; I derived this mostly from Bullimore's posts as well as excursion, distortion, klippel, and other data that has been posted.

                Though, honestly, I'm not using it as a hard and fast limit like I am for the PR's or for other drivers. I DO, however, use the 45mm xmech as a more rigid limit. Even with over 2000 watts, I haven't seen more than ~25mm in sims anywhere above 20 hz. Below 15hz without a high pass filter, you will see it approach 45mm or surpass it, but I have serious doubts as to whether or not even a Crown XLS will output usable power at 10 hz with significant rolloff. I know the iNuke won't - behringer even shows you the amp response rolling off below 20 hz in the spec sheet. So I'm really focused on keeping Xmax below 23 mm above 20 hz, but I'm not really terribly concerned with it like I am with other drivers. Perez (can't remember his first name or username on here) posted a video of this thing plugged in to a wall outlet without bottoming out! With that kind of suspension, I'm just not that worried about it.

                I'm working out of town this week but would be happy to collaborate more and post some of my sims later.

                Comment


                • #23
                  With the type of egregious power that the KRL4000 puts out, you might be temped to put it in a sealed box with lots of boost. This will work fine, except you WILL see 45mm xmax with half that input power, IIRC. In WinISD, there is a tab for Amplifier Apparent Voltage or something like that - not sure if your program has it but I'm sure somebody can chime in. I'm sure you already know this, but if you use, say, 500 watts as your input power but add 3db of boost, the amplifier has to supply 1000 watts at the boosted frequency. 6db - 2000 watts and so on. My only complaint about this is the overall SPL will suffer, even with the boost. But, Bullimore did say that he prefers this sub in a small sealed cab with a little bit of boost. I'm guessing he doesn't turn on the intro to Live, Die, Repeat: Edge of Tomorrow for kicks and grins... For music, I would be very tempted to go this route. For HT and music, vented or PR is way more efficient in the low bass region (something bcodemz pointed out on an earlier post). So that's what I'm pursuing.

                  Instead, a dB or two or three around 20 or 22 hz should allow you to use a smaller box (see what 3 or 3.5 cubes gets you) and flatten out the drooping low end response that accompanies it. Just have to monitor the PR excursion at that level...

                  Comment


                  • #24
                    Originally posted by Blenton View Post

                    This has been beat to death on this and other forums. A little bit of marketing but a lot of engineering has been put in to this driver to make it work as it does - big driver, small box, low tuning, gobs of power handling, insane amounts of excursion. I can't pretend to know the intricacies of loudspeaker motor design, but I think the key is "no MAJOR loss" in motor strength. bcodemz explained some of the advantages of the motor design with that ginourmous coild and what it will get you in real life. I mean, it would seem to reason that there is so much wire on an almost 8" coil that even if half of it left the gap, you would still have more wire in the gap than most any other driver with a 4" or small voice coil!

                    If everybody and their dog hadn't run poor George Bullimore gbullimore off every other forum for bestowing an amazing driver on the DIY community, only to have everyone pough pough on a single parameter that is very poorly defined by ANY manufacturer (coil vs gap / 2, coil vs gap /2 * 15%, coil vs gap /2 *30%, klippeled 10 %, klippeled 15%, yadayadayada) then argue with the man who designed it, positing that they (the DIY community members) know sooooo much more than the Tymphany designers when it comes designing a good driver instead of, oh, I dunno, asking productive questions.. Like why they rated Xmax at 10.2 mm or what they mean by "no major loss in motor strength" and what this driver excels at. Instead, it was the usually inflammatory defamation of a driver being scrutinized on paper while simply dismissing the few with first hand experience or any knowledge on the matter. Ugh. Sorry. Bigger rant. Just wish I was around when George was frequenting the forum - would have loved to pick his brain before everyone started lobbing flaming brown paper bags of excrement at his front door.

                    So, I guess that means I'm doubling down on the STW-350F. Ha! Adding another one to the cart this weekend...

                    And, if you feel that those comments were in any way berating or derogatory and aimed at you - they were not. I'm not lobbing flaming paper at anyone here. I don't feel it is productive to point fingers and start a flaming war so please don't misunderstand my intentions or words. Just wanted to set up my straw man that was made from other peoples' words and burn the thing to the ground.
                    Nah - no offense taken. I was admin on a couple of popular car audio boards for years. I don't get worried until someone threatens to kill me..

                    And honestly, although I have been in the electronics industry since 1990, my interest in DIY home audio really only ramped up a few months ago. I had never heard of this driver before this thread so my earlier post was carefully worded as 'interesting' rather than 'bu||@h*t' Who am I to say their engineering is incorrect.

                    FWIW, I am a HUGE fan of vented boxes. PRs are cool but give me a couple of big ol' vents any day!

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