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Flex Your PCD Mettle:

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  • Re: Flex Your PCD Mettle:

    I auditioned it last weekend before increasing the baffle step that 1.5 dB, which improved it further. I cannot pretend to hear the other changes, but I'm going with the data. It's not eWave Deluxe, but close....

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    • Re: Flex Your PCD Mettle:

      Here are a few off axis plots.
      Attached Files

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      • Re: Flex Your PCD Mettle:

        Originally posted by scitizen17 View Post
        Here are a few off axis plots.

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        • Re: Flex Your PCD Mettle:

          Yes, that is correct.

          Scott

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          • Re: Delite 10e

            Added woofer polars above:

            http://techtalk.parts-express.com/sh...79#post1647179

            Directivity:








            Cumulative Spectral Decay:



            Attached Files
            Last edited by Zilch; 05-31-2010, 07:31 PM.

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            • Re: Flex Your PCD Mettle:

              Zilch,

              What is your overall impression of the plots I posted?

              These measurements were taken in a room (basically a workshop) approximately 30' x 60' with several wall shelves, lots of cardboard boxes, a couple of columns, several desks, and other various and sundry items scattered about. Acoustic tile ceiling (9 ft.) and ceramic tile floor. The speakers were placed about 40" off the floor. Does the 1 meter measuring distance negate these factors?

              Comment


              • Re: Flex Your PCD Mettle:

                Originally posted by scitizen17 View Post
                Does the 1 meter measuring distance negate these factors?
                It does for gated measurements.

                In a large room like that, the room modes don't much affect the low frequencies in your ungated measurements, and the smoothing takes out the hash at the high ones, so I'm considering those the most representative of the actual response among what you have shown.

                The horn appears to be and exponential with a relatively narrower beamwidth at the high frequencies, and thus, is not constant directivity. Notwithstanding this, the speakers should sound quite good and image well when toed in toward the listener....

                Comment


                • Re: Flex Your PCD Mettle:

                  Thanks very much for your comments. They do indeed sound very good to me, and I have been listening to them with zero toe-in, as I usually do with most systems to achieve the best imaging in my opinion. For that reason I have opted to leave the high frequency driver "slightly" hot with regards to the woofer sensitivity. It appears that the most satisfying listening distance is at the equilateral triangle configuration.

                  Originally posted by Zilch View Post
                  It does for gated measurements.

                  In a large room like that, the room modes don't much affect the low frequencies in your ungated measurements, and the smoothing takes out the hash at the high ones, so I'm considering those the most representative of the actual response among what you have shown.

                  The horn appears to be and exponential with a relatively narrower beamwidth at the high frequencies, and thus, is not constant directivity. Notwithstanding this, the speakers should sound quite good and image well when toed in toward the listener....

                  Comment


                  • Re: Flex Your PCD Mettle:

                    Great to see the nuts and bolts of the actual software.
                    Thanks for posting that.


                    Originally posted by Zilch View Post
                    Pete requested some additional measurements with the L-pad set at 3:00 in lieu of 1:00, which are attached below.

                    Also, here are the offsets as I presently have them, on the forward axis:

                    http://www.nytimes.com/2010/10/14/bu...html?src=busln

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

                    Comment


                    • Re: Flex Your PCD Mettle:

                      Originally posted by Skywave-Rider View Post
                      Great to see the nuts and bolts of the actual software.
                      As you see, we're ignoring the woofer Z offset and just working with the differential. I'm deriving that indirectly from the measured location of the maximal inverse null, using which method, I can peg it within a fraction of a mm, but haven't yet come up with a rational result once putting the woofer into the mix. As long as the design center is near the midpoint between the drivers, where the original data is taken, we are still able get mighty close with the filter design.

                      [No, I didn't figure that all out; it just happened.... :p ]

                      Comment


                      • Re: Flex Your PCD Mettle:

                        Originally posted by Zilch View Post
                        I auditioned it last weekend before increasing the baffle step that 1.5 dB, which improved it further. I cannot pretend to hear the other changes, but I'm going with the data. It's not eWave Deluxe, but close....
                        Thanks Zilch, looks like you produced another low cost winner.

                        Could you explain the difference in this one vs the deluxe ewave?

                        Comment


                        • Re: Flex Your PCD Mettle:

                          Originally posted by penngray View Post
                          Thanks Zilch, looks like you produced another low cost winner.

                          Could you explain the difference in this one vs the deluxe ewave?
                          Hi, Penn,

                          Don't know how many have picked up on it yet, but I've done all of these with basically the same woofer/waveguide center-to-center distance, so the primary variable in establishing the height of the forward vertical lobe is the crossover frequency, and we can see that, even with its 12" woofer, Deluxe achieves a more relaxed alignment. Delite 10e uses the 122i waveguide, which imposes additional constraints due to its pattern control limitations. A substantial proportion of its 10" diameter is dedicated to roundover, and if my data is correct, operatively, it is a "small" waveguide not suited for use at so low a crossover frequency as some may have presumed.

                          Somebody's going to have to mount 122i on a flat baffle with a bigger motor than CDX1-1425 to obtain more definitive data with respect to its capabilities than this build has demonstrated. Usable within these limits? Yes, but not much more, until proven otherwise. I'll be working up the summary for Delite 10e this weekend and posting it. A remeasure of Deluxe horizontal polars should appear here soon, as well, now that I am better set up with a rotary table to do that....

                          Comment


                          • Re: Flex Your PCD Mettle:

                            Added nearfield low frequency response, this post:

                            http://techtalk.parts-express.com/sh...65#post1646965

                            And re-measured eWave Deluxe horizontal polars here:

                            http://techtalk.parts-express.com/sh...10#post1625810
                            Last edited by Zilch; 05-30-2010, 02:41 AM.

                            Comment


                            • Re: Flex Your PCD Mettle:

                              Originally posted by Skywave-Rider View Post
                              Zilch, Are both of these horizontal?
                              Yes.

                              See Atkinson's normalized one on JBL Array 1400 here:

                              http://www.stereophile.com/floorloud...er/index5.html

                              And Revel Ultima Salon2:

                              http://www.stereophile.com/floorloud...el/index5.html

                              I have to do a bit of cleanup on a couple of the others, but after posting the Delite 10e summary, I'll put up a toggle post for fun....

                              Comment

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