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  • Re: Flex Your PCD Mettle:

    Originally posted by jayhawk785 View Post
    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.
    If you have EQ available, you can port even that smaller enclosure and extend the bass into the upper 30s with the right tune (as Zilch mentioned).

    Without EQ, you won't be reaching into the 40s, and you have to be careful of tuning too high and getting a peaky bass response.

    When I get home from my last day at work here, I can run a sim on the posted TS specs and see what happens.
    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:

      If you have EQ available, you can port even that smaller enclosure and extend the bass into the upper 30s with the right tune (as Zilch mentioned).

      Without EQ, you won't be reaching into the 40s, and you have to be careful of tuning too high and getting a peaky bass response.

      When I get home from my last day at work here, I can run a sim on the posted TS specs and see what happens.
      that'd be fantastic.

      per the eq recommendations, is that completely in lieu of a passive crossover?

      adding a couple mini dsp's to do it is what I'd be doing instead? I'd be completely out of my element there, I can follow directions and handle the woodworking side--but the crossover design and tweaking is over my head.

      I could cut open the bottom and add another chamber for another cubic foot or so, it wouldn't set these guys up to high. they'll be behind a screen so im not overly concerned that they look living room worthy

      last day at work--i've always hated when i give my notice and they actually make me work it. Love it when companies pay you the two weeks and send you on your way

      Comment


      • Re: Flex Your PCD Mettle:

        Originally posted by jayhawk785 View Post

        last day at work--i've always hated when i give my notice and they actually make me work it. Love it when companies pay you the two weeks and send you on your way
        I was notified back in March 2010 that my position was no longer needed, and was given an 11 month severance package. A few months later, they hired me back for a contract stint with another internal group. That ended last August. In November, they called me back again. That stint ends tomorrow, and the severance picks up again.

        Now, it's on to full time speaker building and audio work in general with Vapor. May even be "repping" Arte Forma gear soon. Been dreaming about doing this next phase for most of my adult life. I'm both excited and apprehensive for obvious reasons, but I'm teaming up with some very gifted folks and have very high hopes.

        Wish me luck!!! ;)
        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:

          sounds like a fun and exciting opportunity. also sounds like they cancelled your position prematurely

          *best of luck!

          and I look forward to what you see port wise for this thing with that internal volume

          Comment


          • Re: Flex Your PCD Mettle:

            Originally posted by jayhawk785 View Post
            sounds like a fun and exciting opportunity. also sounds like they cancelled your position prematurely

            *best of luck!

            and I look forward to what you see port wise for this thing with that internal volume
            Thanks. By the way, I was born in Lawrence!
            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:

              Thanks. By the way, I was born in Lawrence!
              me too! Lawrence Memorial Hospital circa bicentennial

              Comment


              • Re: Flex Your PCD Mettle:

                Originally posted by jayhawk785 View Post
                me too! Lawrence Memorial Hospital circa bicentennial
                got you beat by about 20 years!
                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:

                  got you beat by about 20 years!
                  heh, probably didnt run into each other then ;)

                  2/3 speakers are here. everything should be here by wednesday...



                  got all the boxes done--just need to figure out port/length, tune. I also figure I can add a base to them which would give me another .75cu ft if needed.

                  Comment


                  • Re: Flex Your PCD Mettle:

                    Well, I ran a sim using 1.8 cubic feet, and a 45Hz tune, and assuming .3 Ohm series resistance to account for wiring and the inductor. 50Hz F3, which is quite respectable. 6.5" long, 4" diamter port. Add a peaking 2nd order HP, 6dB boost at 35Hz, and increase the port to 12" long, you'll get 35Hz F3 with good woofer control to tuning.

                    Or, increase the enclosure to as much as 3cf, with a 40Hz tune, and get F3 of 40Hz with a 4" long, 4" diameter port.
                    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:

                      Well, I ran a sim using 1.8 cubic feet, and a 45Hz tune, and assuming .3 Ohm series resistance to account for wiring and the inductor. 50Hz F3, which is quite respectable. 6.5" long, 4" diamter port. Add a peaking 2nd order HP, 6dB boost at 35Hz, and increase the port to 12" long, you'll get 35Hz F3 with good woofer control to tuning.

                      Or, increase the enclosure to as much as 3cf, with a 40Hz tune, and get F3 of 40Hz with a 4" long, 4" diameter port.
                      so if i go the boost route, with an active crossover--do you recommend the minidsps or something else? --does it take the place of the passive crossover--or call for a redesign?

                      appreciate the simulation--I'll see what it would take to get me to 3cu feet (without looking ridiculous)

                      Comment


                      • Re: Flex Your PCD Mettle:

                        Originally posted by jayhawk785 View Post
                        so if i go the boost route, with an active crossover--do you recommend the minidsps or something else? --does it take the place of the passive crossover--or call for a redesign?

                        appreciate the simulation--I'll see what it would take to get me to 3cu feet (without looking ridiculous)
                        If you use miniDSP, that's probably the easiest solution, if you can program the type of HP filter described. I'm not sure that's a built in function, a peaking 2nd order HP, but if it is, you're in. Just insert it at the input of the amp.

                        The passive XO remains either way, unless you want to add more amps and replace the XO between woofer and tweeter. But I'd question that since the XO is so simple to begin with.
                        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:

                          If you use miniDSP, that's probably the easiest solution, if you can program the type of HP filter described. I'm not sure that's a built in function, a peaking 2nd order HP, but if it is, you're in. Just insert it at the input of the amp.

                          The passive XO remains either way, unless you want to add more amps and replace the XO between woofer and tweeter. But I'd question that since the XO is so simple to begin with.
                          Hm, so now i have to decide what to do there eh. I'm guessing I'd need two minidsps--dont think they make one with more than 2 channels in.

                          otherwise figure out how to expand the bottom a bit on the finished boxes and increase the volume...

                          Comment


                          • Re: Flex Your PCD Mettle:

                            Originally posted by jayhawk785 View Post
                            Hm, so now i have to decide what to do there eh. I'm guessing I'd need two minidsps--dont think they make one with more than 2 channels in.

                            otherwise figure out how to expand the bottom a bit on the finished boxes and increase the volume...
                            If you use the MiniDSP, and implement the boost, you can use your existing cabinets.
                            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:

                              You can build them with the passive networks and probably get better results.
                              As for the boost, you can use an amp with DSP to make the filter, the newish behringer inuke line with DSP come to mind or you can use something like a DEQ2496 or MIC2200 to get it done.
                              Regards,
                              Dan

                              Comment


                              • Re: Flex Your PCD Mettle:

                                Originally posted by NEO Dan View Post
                                You can build them with the passive networks and probably get better results.
                                As for the boost, you can use an amp with DSP to make the filter, the newish behringer inuke line with DSP come to mind or you can use something like a DEQ2496 or MIC2200 to get it done.
                                Hmm the inukes look intriguing and aren't too expensive.... Two nu1000s would work ok there... Will it do what I need it to do to keep the boxes the same size / active xover...?

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