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EPI-like woofer-tweeter modules

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  • #31
    +1 for H1411. That's the driver that I was going to use to build some retro speakers to go with my Pioneer SX-850. I really miss my EPI 180s !

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    • #32
      I have some old EPI speakers. The drivers were refoamed at some point. If there's interest, I can do a spread of measurements on the tweeter for dispersion and distortion.

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      • #33
        Also, from the direct acoustics website:
        Physical Dimensions

        From my understanding of the science of loudspeaker design, I understand that there are more then (Einstein’s) four dimensions. By revelation, I understand that there are twenty-seven such dimensions.
        How do we make use of these dimensions to improve bass response in a loudspeaker which won't piss of our spouses?

        Comment


        • #34
          Originally posted by dynamo View Post
          Not sure how much you want to spend, but the seas H1411 fits the bill almost perfectly, and is one of probably very few modern drivers to do so. Looks at first glance you will want to plug your port and run it sealed. Might need to dial the mid and tweeter back a dB or two.

          There just aren’t a lot of drivers made anymore that just roll off smoothly around 1k or less and can be run with no crossover or notches. The Burhoe drivers seem to do that well. Obviously no crossover means no bsc, so lack of low end may also be if the speakers are on stands and/ or out from the wall. They will need to be close to the floor or wall behind them to reinforce the bass.
          Thanks dynamo,

          I have noticed that these speakers (even when they had the original woofers) were quite sensative to positioning....but man once you got it right they were on time!

          Theres not a whole lot of technical information I can find on the design of the EPI / Burhoe woofer, Winslow seems to be a man of few words when it comes to trade secrets and who could blame him.....
          His quote I referenced a couple posts up states "acheiving the roll-off was mechanical involving mass of voice coil and compliance of cone material......using a long voice coil and symetrical pole piece geometry"

          "mass of voice coil" in this context (i'm assuming) is resistance to acceleration, so is this referencing lighter or heavier?

          Aside from tearing apart a speaker there doesn't seem to be a way to confirm these attributes? The seas parameters for the H1411 list the voice coil height as 14mm and max coil travel at 35mm, so in this case i'm assuming VC length is a little more than the max travel? Most manufacturers don't offer those specs though.

          Is there anything to be learned regarding the pole piece geometry from the 'magnetic gap flux density' spec?

          The H1411 seems basically the newer version of the 25 tv-ew that lasse referenced? The Qts for the H1411 is .39 so that might work either sealed or ported ....is there another spec hinting otherwise? I've got a couple nice 'test' boxes that are 10" 2 way sealed ( advent legacy and AR 38) to try them in also.

          And hey.......cash is fleeting, high fidelity is an investment in the soul! (at least thats the crap I feed the wife!)

          I'm quite interested in the whole EPI / Burhoe dynamic with the KISS method and the clean sounds that result, certainly would like to continue down that path in future projects......understanding it is half the battle.

          any more education would be greatly appreciated!

          Bob

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          • #35
            Originally posted by civit View Post
            Also, from the direct acoustics website:


            How do we make use of these dimensions to improve bass response in a loudspeaker which won't piss of our spouses?
            mushroom tea ; )

            Comment


            • #36
              Originally posted by civit View Post
              I have some old EPI speakers. The drivers were refoamed at some point. If there's interest, I can do a spread of measurements on the tweeter for dispersion and distortion.
              you can't know too much......bring it civit !

              to compliment the H1411 they recoed a seas prestige 27 TDFC (H1189) and I was also eyeballing the seas E0055-06 T35C002 1.5" tweet or maybe that new peerless everyones going on about.

              Comment


              • #37
                Originally posted by Mountainman Bob View Post

                Thanks dynamo,

                I have noticed that these speakers (even when they had the original woofers) were quite sensative to positioning....but man once you got it right they were on time!

                Theres not a whole lot of technical information I can find on the design of the EPI / Burhoe woofer, Winslow seems to be a man of few words when it comes to trade secrets and who could blame him.....
                His quote I referenced a couple posts up states "acheiving the roll-off was mechanical involving mass of voice coil and compliance of cone material......using a long voice coil and symetrical pole piece geometry"

                "mass of voice coil" in this context (i'm assuming) is resistance to acceleration, so is this referencing lighter or heavier?

                Aside from tearing apart a speaker there doesn't seem to be a way to confirm these attributes? The seas parameters for the H1411 list the voice coil height as 14mm and max coil travel at 35mm, so in this case i'm assuming VC length is a little more than the max travel? Most manufacturers don't offer those specs though.

                Is there anything to be learned regarding the pole piece geometry from the 'magnetic gap flux density' spec?

                The H1411 seems basically the newer version of the 25 tv-ew that lasse referenced? The Qts for the H1411 is .39 so that might work either sealed or ported ....is there another spec hinting otherwise? I've got a couple nice 'test' boxes that are 10" 2 way sealed ( advent legacy and AR 38) to try them in also.

                And hey.......cash is fleeting, high fidelity is an investment in the soul! (at least thats the crap I feed the wife!)

                I'm quite interested in the whole EPI / Burhoe dynamic with the KISS method and the clean sounds that result, certainly would like to continue down that path in future projects......understanding it is half the battle.

                any more education would be greatly appreciated!

                Bob
                Regarding the moving mass I’m assuming it is higher causing a lower frequency mechanical roll off. I’m also going to guess the cone is a little more compliant. Nowadays stiff light cones are the in thing resulting in extended response and significant breakup.

                with the seas I believe the 14mm coil height is indicating + / - 7mm or so linear where the coil is in the gap and the 35mm is indicating a + / - 17.5mm xmech, mechanical limit of excursion. Both specs are respectable imo.
                Projects:

                Breezy Monitors: http://techtalk.parts-express.com/fo...reezy-monitors
                transcenD: http://techtalk.parts-express.com/fo...5035-transcend
                Summits: http://techtalk.parts-express.com/sh...75-The-Summits
                References: http://techtalk.parts-express.com/sh...-My-References
                Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

                Comment


                • #38
                  Well I suppose theres only one way to find out ! 'The other guys' actually have a kit that replicates the dynaco A25 that uses the H1411 / E0055-06 with just a 3.3 uf cap and 8,10, or 12 ohm resistor.

                  why doesn't PE sell seas ?

                  Comment


                  • #39
                    Contract I suppose. It appears seas and scanspeak both only have one distributor per country, and for those brands it appears the other guys are it. Plenty of fine products at PE but if you need or want one of those two you need to go there I guess.
                    Projects:

                    Breezy Monitors: http://techtalk.parts-express.com/fo...reezy-monitors
                    transcenD: http://techtalk.parts-express.com/fo...5035-transcend
                    Summits: http://techtalk.parts-express.com/sh...75-The-Summits
                    References: http://techtalk.parts-express.com/sh...-My-References
                    Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

                    Comment


                    • #40
                      10-4

                      I don't suppose PE likes people using their forums for competative products.........Winslow did say a woofer was sold here that matched up but didn't give detail, does PE offer anything remotely comparable?

                      Comment


                      • #41
                        Nothing that stood out to me. Not sure which one he was referencing. That seas unit is really one of the only drivers currently made that I know of that is specifically geared for your type of application.

                        PE understands they can’t carry every product and if they don’t have one that fits your needs then so be it. Forum rules do not prohibit discussion about products they do not carry, it only prohibits links to competitor websites. For example I could link the seas site for that driver but not the retailer that sells it.
                        Projects:

                        Breezy Monitors: http://techtalk.parts-express.com/fo...reezy-monitors
                        transcenD: http://techtalk.parts-express.com/fo...5035-transcend
                        Summits: http://techtalk.parts-express.com/sh...75-The-Summits
                        References: http://techtalk.parts-express.com/sh...-My-References
                        Vintage Style 2-way: http://techtalk.parts-express.com/sh...-vintage-2-way

                        Comment


                        • #42
                          I think the InDIYanna 2019 post /vote may be leaning towards 8" with dome 2-way. I would be curious how Winslow's design would hold up to some modern drivers and of
                          course an x-over that was more than a single cap. I was fortunate to meet Mr.Burhoe at NE/DIY one year and most people would have loved to pick his brain for a
                          couple hrs. but he did give a short discussion when he demo'ed his latest design. Maybe 2014/2015 in RI

                          Comment


                          • #43
                            Here are some crude measurements of the HF unit on my EPI A110s. These were done on baffle, from about 2.5' away. 0, 15, 30 and 45 degrees included. No crossover.
                            Click image for larger version  Name:	 Views:	1 Size:	137.7 KB ID:	1378188


                            Here are some distortion figures from Arta/STEPS. These were done at around 3" away, with the level set to 100db @ 1000hz.

                            Click image for larger version

Name:	
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                            Note that my distortion testing acumen is low and these should be taken with a grain of salt. 1/48 octave resolution.



                            Here's the back of the tweeter in question. Crossover for this tweeter includes one capacitor and one inductor.

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                            • #44
                              Well tried a couple different value air chokes in line with the woofer to see if it would smooth out the transition, tried one which low passed at 4500hz; way above the tweets high pass of 2500hz......was trying to initiate the natural rolloff aspect a little earlier and maybe smoother.

                              Also tried one that put the low and high pass right about at the the same 2500hz the way its supposed to be (Isuppose!)

                              I figured out that anything you add to the signal, even with the higher end components apples for apples..... makes things sound like arse!

                              I really don't understand why more manufacturers don't try to improve on this simple but effective design......strikes me a bit funny that only one woofer is made today for this application! ....well two if you count the Human. I wonder if there are more choices in the 8" woofer range?

                              These PA255-8 10" pro woofers wired straight really arent bad at all as long as you stay off axis a bit......still gonna start putting money back to make a set of those seas A26 (H1411/T35C) for the #1 system.

                              Frustrating stuff I tell ya what !

                              Comment


                              • #45
                                What about the Dayton RS270P-8A It checks alot of boxes....paper cone,low qts, 6mm xmax,low f3, fairly smooth roll off ? Hows it look to you fellers? vented volume is 1.43 and i'm at 1.45 go figure!

                                less sensative but i'm a little hot at 92 db with the PA255

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