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Flex Your PCD Mettle:

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  • Re: Flex Your PCD Mettle:

    Originally posted by edlafontaine View Post
    Zilch, Pete, see the original post:

    http://techtalk.parts-express.com/sh...&postcount=153

    I'm trying to get caught up on my home work and ready for Iowa. Can you clarify the work done in smoothing the DeLite 12 response around 2.2K? A schematic (or description of tap points) would be most helpful. I'd like to bring and show this along with "stock".
    Pete offered up a more sophisticated highpass with an impedance-correcting RCL notch (1.0mH, 8uF, 8R0) on the DE250 at #150:

    http://techtalk.parts-express.com/sh...03#post1634503

    I prototyped it and compared to my earlier version at #153, with changes in the component values as noted. Those changes were not arbitrary; I tried it with the specified values and tweaked it based upon the measured response. You can see the "spare" components at the lower left in the pic at #155, the 1.0 mH from the notch and the 2.2uF swapped out from the HF comp RC filter. The notch filter is there seen alligator'd across the L-pad; that's 8.2 uF in it, as 8.0uF is not standard.

    Ultimately, 12 days later, I went with Pete's simpler filter for "stock." That much time implies that I listened and compared, weighing the tradeoffs between performance and filter complexity before committing to final. The date stamp on the crossover plot is 4/7, so it's clear that I built it up for a final check, including measuring the vertical polars and finding the forward axis.

    I think you're on an good track here; it'll be interesting to learn whether you'd have made the same choice, based upon the final performance in your build....

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    • EconoWave HP - High Power Pro

















      Attached Files
      Last edited by Zilch; 08-31-2010, 10:31 PM.

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      • Re: Flex Your PCD Mettle:

        What's the story with this odd ball WG?

        http://www.parts-express.com/pe/show...umber=292-2576



        Lot's of good things about the Nexo PS8 of which this appears could possibly be a knock off of.

        http://www.nexo-sa.com/user/data/PS-R2BROCHURE.pdf

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        • Re: Flex Your PCD Mettle:

          Originally posted by Zilch View Post
          What HF driver did you run on 612?

          Never tried DE250 on 122i; Delite 10e was based upon Celestion 1425 and crossed high. It may work out better with DE250.

          All variants you are contemplating will require crossover development work except Delite 10 using XT1086. None on eBay active or completed right now, but we know they're out there. Penn have a pair he'll sell you, maybe?
          Haven't tried 612.....and given the cost vs 152i can't find a reason to. The SR XO measured soooo well that it suggests to my eyes that 220Ti and 152i are the budget combo of the year.:D

          With comparative measurments from your graphs, 2510 and Dayton PA310 are quite comparable on performance with the nod goin' to 2510 for better LF extension. I think i'll start with the HP section of SR and the LP section of Delite10.....level wise it's near an exact match.

          If i can pursuade Penn to part with his XT1086's then i'm all good......as long as 220Ti works well on em. I don't think you've ever tried that combo but the engineering is there with XT so overall, i'm optomistic.

          Don't know if you've followed along a discussion on AVS using side by side 6-8" drivers below AND above h152i possibly 8 rows of 2 for 16 in total. 16 Buyout 6.5's...cheaper than 3015....Hmmmmmmm:rolleyes:

          Would be loud as [email protected]&K that's for sure.....and pretty not bad to look at as well.

          Comment


          • Re: Flex Your PCD Mettle:

            Originally posted by Mayhem13 View Post
            What's the story with this odd ball WG?

            http://www.parts-express.com/pe/show...umber=292-2576
            Asymmetric, though neither Pyle nor Parts Express seems to know that.

            Could do the image stabilization thing, maybe, if the pattern is right.

            I've built up a pair, but haven't had opportunity to measure them yet; I'm doing the Altec thing next....

            Comment


            • Re: Flex Your PCD Mettle:

              Originally posted by Zilch View Post
              Asymmetric, though neither Pyle nor Parts Express seems to know that.

              Could do the image stabilization thing, maybe, if the pattern is right.

              I've built up a pair, but haven't had opportunity to measure them yet; I'm doing the Altec thing next....
              Nexo know it......and the response sims seem to sya maybe not for home use with a wide horizontal dispersion in the nearfield?

              I'll finish my bass bins and box tops without baffles for 2510 while you get around to the Pyle round.

              Still think RCF H100 might be a cost effective choice. Those Fascists seem to be serious when it comes to sound! Mussolini would be proud!

              Comment


              • Re: Flex Your PCD Mettle:

                Still working on a driver combo and box modeling. So I don't plan too shallow, what's the depth of the 152i waveguide with the d220ti or B&C250 CD attached?

                Tough time deciding between the SR and Deluxe. Does the SR work out to be a few DB more efficient, being that the 310-8 starts out a few DB higher? I can't interpret the graphs to figure that one out. And would that make a lick of difference with a 100w HT receiver...?

                Is the prime advantage sonically of the deluxe allowing lower F3 and more low boost without running out of xmax for non-sub situations? Zilch mentioned that they are sonically similar - but that's a pretty vague phrase (no offense). Could you clarify that at all?

                Oh, and my waveguides are en-route via FedEx. Whoo hoo!

                C.
                Last edited by Cerdic; 08-31-2010, 11:14 PM.

                Comment


                • Re: Flex Your PCD Mettle:

                  SR is substantially more efficient than Deluxe according to the measurements.
                  It clearly doesn't have the bass extension that Deluxe has........but that's what subs are for.:D Relocating the LF to a sub instead of the 12" midwoofer can only aid in midrange clarity if nothing else.

                  It's been tossed around that the Ti diaphram of the 220Ti isn't as smooth as the non metallic B&C DE250. Is it $85 better??.....there's tougher questions out there that need answerin':p

                  Comment


                  • Re: Flex Your PCD Mettle:

                    Originally posted by Mayhem13 View Post
                    Nexo know it......and the response sims seem to sya maybe not for home use with a wide horizontal dispersion in the nearfield?

                    I'll finish my bass bins and box tops without baffles for 2510 while you get around to the Pyle round.

                    Still think RCF H100 might be a cost effective choice. Those Fascists seem to be serious when it comes to sound! Mussolini would be proud!
                    Easy on the offensive statements. I'll make you a deal. You delete that post. Then I'll delete this. In that order.
                    http://www.nytimes.com/2010/10/14/bu...html?src=busln

                    http://mixonline.com/mag/audio_new_york_metro_46/

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                    • Re: Flex Your PCD Mettle:

                      What do we have left without a sense of humour.....I'm of italian decent myself and i stand by my heritage......and my post. Sorry if the terms Fascist and political figures such as Mussolini offend you.

                      Comment


                      • Re: Flex Your PCD Mettle:

                        Spanning a budget spectrum from $113 to $897:



                        The project index is in Post #1

                        Click "First" at the top or bottom of any page in this thread to go there:

                        http://techtalk.parts-express.com/sh...95#post1617195

                        Comment


                        • Re: Flex Your PCD Mettle:

                          I'm glad you put that list together Zilch.

                          It would have saved me a lot of time comparing Woofer / CD / Waveguide combinations.

                          Comment


                          • Re: Flex Your PCD Mettle:

                            Dropping the high and low, average total cost is $310, looks like.

                            Not cheap, but clearly the paradigm value leader....

                            Comment


                            • Re: Flex Your PCD Mettle:

                              http://techtalk.parts-express.com/at...7&d=1281207066

                              Zilch, do you want to have the back of the drivers line up? I know this was mentioned before in order to not tilt the axis but I couldn't remember where the reference point on the drivers were relative to alignment.
                              My simple speaker project
                              My simple subwoofer project

                              The Inlaws Hometheater

                              Comment


                              • Re: Flex Your PCD Mettle:

                                Originally posted by stgdz View Post
                                http://techtalk.parts-express.com/at...7&d=1281207066

                                Zilch, do you want to have the back of the drivers line up? I know this was mentioned before in order to not tilt the axis but I couldn't remember where the reference point on the drivers were relative to alignment.
                                It's a crap shoot, really; the acoustic center of the driver is rarely where conventional wisdom would suppose it to be. The only way to know is by measurement. We set the alignment by guessing to minimize the offset, then adjust the phase delay in the crossover to have the acoustical sum line up on the desired forward design axis.

                                Not everybody pays attention to this, but it's a significant factor in waveguide system design, where the center-to-center distance between drivers is comparatively large. See Wayne's video illustrating:

                                http://www.pispeakers.com/misc/Vertical_Nulls.wmv

                                Generally speaking, matching the physical alignment used in the development will yield the desired result. It's easy to check with measurement gear: invert the polarity of one of the drivers and find the vertical location of the mic where the interference null at crossover is deepest. Move the waveguide more forward relative to the woofer, and the axis moves downward, and vice-versa....

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