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ATTENTION: Continuum Builders

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  • ATTENTION: Continuum Builders

    I have received three complaints of the Continuum being too bright in the treble. Two of these units were measured, and their results were essentially identical - showing the entire tweeter level about 1.5-2 dB higher than flat for the summed response. However, my sample, and Jim Salk's sample measured much flatter through the treble, as I intended the speaker to be.

    It makes me wonder if the RS28a varies in sensitivity a couple of dB. I know I have heard four other versions of the speaker from other builders and never noticed a high frequency over-emphasis in them, but the I believe the reports and measurements from the ones that have contacted me about it, as it was enough of an emphasis that they noticed it, and the measurements appear to confirm it.

    As a result of the first person to request a way to lower the tweeter I did a little modeling to come up with the best solution. Since the entire tweeter level is high and not just a certain region (more evidence for varying sensitivity), the best solution is to leave the series resistor in the RC circuit unchanged and instead add a parallel resistor (like you see on an L-Pad) between the RC contour circuit and the tweeter. In fact, this resistor could be placed directly across the tweeter's terminals if that works best. We found that a 15 ohm resistor was perfect for the amount of change needed and lowers the overall tweeter level by 1.5dB based on measurements.

    So, if you have felt that the Continuum was bright, but haven't said anything, you may be affected in the same way as these others. Add the 15 ohm resistor and it should correct the issue. The response of the Continuum above 500Hz was designed to be extremely flat as a reference.

    For what it's worth, a 20 Ohm would trim the highs a bit less and a 10 ohm a bit more. Feel free to tweak as desired for the balance that seems right in your room and system.

    Jeff B.
    Click here for Jeff Bagby's Loudspeaker Design Software

  • #2

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    • #3
      Re: ATTENTION: Continuum Builders

      Was it people who used the RS28F instead? (may be a stupid question, but I thought I'd ask just in case)
      Isn't it about time we started answering rhetorical questions?

      Paul Carmody's DIY Audio Projects
      Twitter: @undefinition1

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      • #4
        Was this the old version RS28A?

        Hi Jeff,
        I'm not that familiar with the continuum but the RS28A I sent you was the older ferrofluid version which is, er, a tad less sensitive, by about 2 dB than the newer nonferro version. Not sure if this played any role...
        audioheuristics isn't around right now...

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        • #5
          Re: ATTENTION: Continuum Builders

          Originally posted by Paul Carmody View Post
          Was it people who used the RS28F instead? (may be a stupid question, but I thought I'd ask just in case)
          Nope. RS28a. If someone built with the RS28F then is wasn't a Continuum, and they didn't get any support from me.
          Click here for Jeff Bagby's Loudspeaker Design Software

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          • #6
            Re: Was this the old version RS28A?

            Originally posted by markk View Post
            Hi Jeff,
            I'm not that familiar with the continuum but the RS28A I sent you was the older ferrofluid version which is, er, a tad less sensitive, by about 2 dB than the newer nonferro version. Not sure if this played any role...
            Well, that may explain most of it. I did, in fact, use the older tweeters you sent me. However, Jim's measurements were balanced like mine, and the other speakers I heard at DIY Indiana seemed to sound the same as mine. No one commented on any high frequency difference. Still, I did use the older tweeters in my speakers. I may need to modify the crossover schematic to show the choice of parallel resistors.

            Jeff
            Click here for Jeff Bagby's Loudspeaker Design Software

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            • #7
              Re: ATTENTION: Continuum Builders

              Nice timing Jeff.

              I was literally going to order the crossover components tonight. I am glad I procrastinated and watch Stargate Universe first.
              My projects
              https://picasaweb.google.com/112307725038877176664

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              • #8
                Re: ATTENTION: Continuum Builders

                Originally posted by ckmoore View Post
                Nice timing Jeff.

                I was literally going to order the crossover components tonight. I am glad I procrastinated and watch Stargate Universe first.
                I'm so annoyed I got out of cycle on the stargate universe series after missing a few. I was all ready for season two after watching 1 on blu ray but now have to wait until season two is on blu ray...

                What are we going to do when there are no more stargates to watch. I sucked my wife into watching 10 years' of SG1, atlantis, and now Universe...
                audioheuristics isn't around right now...

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                • #9
                  Re: ATTENTION: Continuum Builders

                  Originally posted by markk View Post
                  What are we going to do when there are no more stargates to watch.. .
                  I don't know... I just don't know. :(

                  If you like Stargate, check out Farscape. A great, underrated show. Just bought the complete series on DVD at Costco.


                  ...sorry for hijack. Back to Continuums.
                  My projects
                  https://picasaweb.google.com/112307725038877176664

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                  • #10
                    Re: ATTENTION: Continuum Builders

                    The last batch of RS28A that I bought (which, granted, was back in the "with ferrofluid" days) had a sensitivity variation of about a dB between the least and most. I just "matched paired" the ones that didn't go into active systems, and of course for the ones that did it didn't matter . . .
                    "It suggests that there is something that is happening in the real system that is not quite captured in the models."

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                    • #11
                      Re: Was this the old version RS28A?

                      Originally posted by Jeff B. View Post
                      Well, that may explain most of it. I did, in fact, use the older tweeters you sent me. However, Jim's measurements were balanced like mine, and the other speakers I heard at DIY Indiana seemed to sound the same as mine. No one commented on any high frequency difference. Still, I did use the older tweeters in my speakers. I may need to modify the crossover schematic to show the choice of parallel resistors.

                      Jeff
                      I am always a little hesistant to make a direct comparison with measurements unless I pair the two off in a single testing session, so I can't be 100% sure of this, but there may be a bit of sensitivity difference with the nonferro being slightly higher. It might not be 2 dB though.

                      Plus, I don't pay uber attention to the absolute sensitivity of drivers since I always measure a design myself, but I can see how that might cause a bit of confusion...:o
                      audioheuristics isn't around right now...

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                      • #12
                        Re: ATTENTION: Continuum Builders

                        Originally posted by ckmoore View Post
                        I don't know... I just don't know. :(

                        If you like Stargate, check out Farscape. A great, underrated show. Just bought the complete series on DVD at Costco.


                        ...sorry for hijack. Back to Continuums.
                        I'm trying to like Farscape. It's on netflix streaming through the wii(hey it works pretty good!). The writing is pretty good but come on, muppets as aliens? And what's with the goofy theme music.

                        What was pretty good was Firefly, but pity that the show ended quickly and is now a cult classic...
                        audioheuristics isn't around right now...

                        Comment


                        • #13
                          Re: ATTENTION: Continuum Builders

                          Originally posted by markk View Post
                          I'm so annoyed I got out of cycle on the stargate universe series after missing a few. I was all ready for season two after watching 1 on blu ray but now have to wait until season two is on blu ray...

                          What are we going to do when there are no more stargates to watch. I sucked my wife into watching 10 years' of SG1, atlantis, and now Universe...
                          SG1 was one of my all-time favorite shows. Absolutely loved it, saw every episode and the movies. I felt the character development and story lines were very well constructed.

                          I watch Universe (it's on the DVR schedule) but It's dark and depressing in comparison. Not quite as easy to love.
                          Click here for Jeff Bagby's Loudspeaker Design Software

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                          • #14
                            Re: Was this the old version RS28A?

                            Originally posted by markk View Post
                            Plus, I don't pay uber attention to the absolute sensitivity of drivers since I always measure a design myself, but I can see how that might cause a bit of confusion...:o
                            One reason I'll likely always use LAUD for all my design work. Absolute measurements of drivers made years apart and auto-adjusted to 2.83v @1m makes a driver substitute in a current design easy. Too bad that Windows screwed up the audio path after Win98.

                            dlr
                            WinPCD - Windows .NET Passive Crossover Designer

                            Dave's Speaker Pages

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                            • #15
                              Re: ATTENTION: Continuum Builders

                              Since we strayed...

                              Firefly was great - damm them for cancelling it!

                              Wendy watches the SG series so I am somewhat up on that one - like some of it, especially the original movie. If it was out from under the syfy umbrella it would have been a much higher quality show - the writing was good.

                              Babylon 5 had great stories but suffered from poor dialogue at times, mostly bad movies, and terrible guest writers. Still liked it though. Of all the guest writers, only Neil Gaiman did it any justice. B5 still gets my vote for the science fictional "best lumbering dreadnought" award - the EA destroyer and definitely best fighters : )

                              To stray back to reality, check this out!!!

                              http://www.adastrarocket.com/aarc/

                              And the flash movie of VASIMR running at 100% in a vacuum chamber - see bottom of page:

                              http://www.adastrarocket.com/aarc/VX200

                              Makes me want to go back to school, I have the "wrenching" experience on HVPS/radar equipment from the Navy.

                              Cheers / Robert

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