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Flex Your PCD Mettle:

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  • Re: Flex Your PCD Mettle:

    Sealed: some built-in protection if they are ever fed with very low frequency energy. Maybe a little easier to integrate with subs, though YMMV. Can stuff the daylights out of the box, to better absorb back wave midfrequencies.

    Vented: less diaphram movement down near where the port contributes, so some more available output there. Less forgiving design if T&S parameters vary. Can't stuff box too much (as it will hurt port efficiency), so gotta be careful to somehow avoid midfrequency reflections back out the cone, or mids leaking out the port.

    Passive: same as vented, except a little more versatile on adjustment (no big tubes inside box, just mess with weight on passive), and better blocking of leaking mids.

    Use WinISD (or similar) and model it with different volumes/tunings. Sometimes the "ideal" box size is way bigger than one that works almost as well but is way smaller.

    If you don't need output below where the sealed box works, I'd go with that. A lot more forgiving of parameters and stuffing.
    Free & Free-form simulator/designer for Passive Crossovers
    SynergyCalc 5: design spreadsheet for Wooden horns and DIY Synergy Waveguides
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    • Re: Flex Your PCD Mettle:

      Originally posted by gmannel View Post
      And finally, if I model the 2512 using TS parameters, etc, rec.box size is 2.37 cf. Manufac spec sheet says 0.8!! What do I believe? That's a huge difference!
      Attached Files

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      • Re: Flex Your PCD Mettle:

        For an updated E-wave mini?
        http://www.eighteensound.com/index.a...roduct&pid=262, plus either this -
        http://www.parts-express.com/pe/show...number=290-507, this -
        http://www.eighteensound.com/index.a...roduct&pid=256, or this -
        http://www.eighteensound.com/index.a...roduct&pid=243??????
        I have the above CD/WG and since neither that nor any of these 3 woofer choices were avail when the orig was developed, I was wondering if these 'model' well?

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        • Re: Flex Your PCD Mettle:

          This is a detailed instruction set from 18sound with similar but older drivers - http://www.eighteensound.com/staticC...Sound_kit8.pdf
          Same build and tweak/redo crossover or bi-amp w/ active(miniDSP)?

          Comment


          • Re: Flex Your PCD Mettle:HP Power Pro

            Originally posted by srbliss
            Hello Pete,
            What is your final design on the crossover on this setup? I have the drivers and really want to make a pair of 'tribute' E-wave speakers honoring Evan. I have the badges ready to go (I fronted most of the $$ to have them made) He helped me more than a lot on my not so Econo JPL pro (2235H and 2452H-SL on PT-F95HF) speakers and I want to do this project right in honor of him.
            Steve
            If you check the very next post, Zilch commented on why it might not be so good to leave it at that setup, due to the vertical directivity.

            The simplest thing to do would be to mount the woofer recessed so that acoustic centers line up.

            But if I recall correctly, the nice plot was derived using the values in the previous post.

            Woofer: 1.2mH, .2 Ohm ; 22uf shunt ; 1mH, .2 Ohm ; zobel 15uF, 8 Ohm

            Tweeter: 1.5uF ; 1.2mH .2 Ohm ; 10uF in series with 3.3 Ohm to tweeter.
            R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

            Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


            95% of Climate Models Agree: The Observations Must be Wrong
            "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

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            • Re: Flex Your PCD Mettle:

              I've begun building the econowave - deluxes, all speakers/waveguides and crossover parts should be here mon/tuesday.

              I started building the boxes, i made them a bit narrower to fit behind my screen.

              dimensions are 17wx25.5hx10.5d (double baffle - woofer recessed to second piece, and opening rounded over) -- using the kappalite 3012lh, do I need to port the box, or will it be fine stuffed/sealed?

              I've read as much as I can in here and other forums--hoping the boxes will be ok as I've made them. Was a bit worried about depth, but I think they should be deep enough. Is there a necessary amount of clearance needed behind either driver? I think as is i should have 1-2" behind either.

              I appreciate any help guys--I never had a chance to know or speak with Zilch and after reading so many threads with his name in it and all the time he's put into this project, I was saddened to hear of his passing.

              THanks-
              steve

              Comment


              • Re: Flex Your PCD Mettle:

                Hey Super Steve,
                You want to build using Z's deluxe crossover, but with Brandon's cab style? You have big round over bits?
                Regards,
                Dan

                Comment


                • Re: Flex Your PCD Mettle:

                  Originally posted by NEO Dan View Post
                  Hey Super Steve,
                  You want to build using Z's deluxe crossover, but with Brandon's cab style? You have big round over bits?
                  I think I have 1.5 and 1.25 inch bits--possibly 1 inch...

                  But ya basically the same style, with the listed deluxe xover (since I have the parts already on the way)

                  I'll post a picture of the cabinet progress tomorrow -- not that the square boxes are exciting

                  Comment


                  • Re: Flex Your PCD Mettle:

                    The roundover looks like it will be the "thing" that determines the distance between drivers, although you can always route into the flat edge of the WG.
                    Regards,
                    Dan

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                    • Re: Flex Your PCD Mettle:

                      How low do you want them to play? Pro drivers don't tend to go too low. Having simmed other pro drivers w/ similar specs, I would suspect you won't get much lower than the high 40's for F10.

                      Depth isn't too critical as long as the driver fits.


                      Originally posted by jayhawk785 View Post
                      . . . -- using the kappalite 3012lh, do I need to port the box, or will it be fine stuffed/sealed?

                      . . .
                      Was a bit worried about depth, but I think they should be deep enough. Is there a necessary amount of clearance needed behind either driver? I think as is i should have 1-2" behind either.


                      THanks-
                      steve
                      I was so much older then, I'm younger than that now.
                      OS MTMs http://techtalk.parts-express.com/sh...d.php?t=220388
                      Swope TM http://techtalk.parts-express.com/sh...d.php?t=221818
                      Econowave and Audio Nirvana AN10 fullrange http://techtalk.parts-express.com/sh...d.php?t=216841
                      Imperial Russian Stouts http://techtalk.parts-express.com/sh...=1#post1840444
                      LECBOS. http://techtalk.parts-express.com/sh...ghlight=lecbos

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                      • Re: Flex Your PCD Mettle:

                        I was hoping for 40's/flat-ish to 50 would be nice...




                        there's the box construction. I have to go get some more mdf tonight --ran out of wood to doublebaffle--had some math issues

                        So, I should be ok with that volume--do i need to port it or just go sealed with some stuffing?

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                        • Re: Flex Your PCD Mettle:

                          The 3012LF should have no problem reaching into the 40s in the right sized cabinet.

                          Fs: 37Hz
                          Qts: .32
                          Vas: 3.8cf

                          Factor in the coil resistance, and Qts moves up, allowing even lower F3.
                          R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

                          Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


                          95% of Climate Models Agree: The Observations Must be Wrong
                          "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

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                          • Re: Flex Your PCD Mettle:

                            The 3012LF should have no problem reaching into the 40s in the right sized cabinet.

                            Fs: 37Hz
                            Qts: .32
                            Vas: 3.8cf

                            Factor in the coil resistance, and Qts moves up, allowing even lower F3.
                            Pete, that's basically my question--what's the right sized cabinet, and should it be ported or sealed? There's really no definitive answer, short of people using the parts express knockdown... which is around 1.6cuft.

                            And as far as porting, there doesnt appear to be anything suggesting for certain that it should or shouldnt be.

                            thanks for all the responses guys--appreciate it.

                            Comment


                            • Re: Flex Your PCD Mettle:

                              Originally posted by jayhawk785 View Post
                              Pete, that's basically my question--what's the right sized cabinet, and should it be ported or sealed? There's really no definitive answer, short of people using the parts express knockdown... which is around 1.6cuft.

                              And as far as porting, there doesnt appear to be anything suggesting for certain that it should or shouldnt be.

                              thanks for all the responses guys--appreciate it.
                              I don't have the modeling software handy at the moment, but a guess, looking at the numbers, you'd need a cabinet of roughly 3cf, with a port tuning around 42Hz, which should give you F3 in the mid 40s. You could probably get away with a 3" diameter flared port. Port length? That's a guess I couldn't make with any confidence.

                              Zilch talked about using an EQ to handle the low end in the knockdown cabinet. If you don't want to use EQ, then a larger cabinet is definitely in order, as in a floor standing tower with the same footprint as the knockdown cabinet.
                              R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

                              Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


                              95% of Climate Models Agree: The Observations Must be Wrong
                              "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

                              Comment


                              • Re: Flex Your PCD Mettle:

                                I don't have the modeling software handy at the moment, but a guess, looking at the numbers, you'd need a cabinet of roughly 3cf, with a port tuning around 42Hz, which should give you F3 in the mid 40s. You could probably get away with a 3" diameter flared port. Port length? That's a guess I couldn't make with any confidence.

                                Zilch talked about using an EQ to handle the low end in the knockdown cabinet. If you don't want to use EQ, then a larger cabinet is definitely in order, as in a floor standing tower with the same footprint as the knockdown cabinet.
                                Pete, I've already created the boxes--my concern is the port/no port at this point. I created them about as large as I could with maintaining the baffle width of the PE box.

                                My interior volume is 1.77604cu ft. Slightly larger than a PE box. I'll try to find the winisd file for the 3012lf driver, but even then id like input on what you guys think in terms of port no port with that box size.

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