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Dayton CBT36K - What do they sound like?

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  • Dayton CBT36K - What do they sound like?

    Hi I am interested in the CBT36Ks. Can someone tell me what they sound like? I understand that the technology is groundbreaking, etc.... however how would they be best described as sounding like a traditional box speaker or something from the magnepan line up? Thanks

  • #2
    Don Keele demo'ed the CBT36 at the Part Express' Midwest Audiofest meeting in Dayton six years ago. He added two subwoofers to handle the bass. Now the meeting room is a large space with high ceiling so listening isn't the same as a normal living room would be. The sound was very good as arrays played with dynamics and sounded effortlessly. Don selected sound effects and music that demonstrated the arrays.

    Keele was back at the MWAF three years ago with the CBT24 arrays which use a full range driver. Again excellent sound and performance.

    You can read more about how the CBT36 perform if you google 'cbt36' and follow some of the threads linked. While several links to photos and such are missing, I would recommend the avsforum thread at:

    https://www.avsforum.com/forum/155-d...t36-array.html

    Read especially Rick Craig's postings and comments (the postings beginning about message 91 are useful. Rick Craig of Selah Audio worked alongside Keele on testing/equalization of the CBT36 which prepared the speakers for later demonstrations.

    Another link with Rick's insight on the CBT36 read this thread on AudioCircle at:

    https://www.audiocircle.com/index.php?topic=108944.0


    Finally, the CBT24 version were reviewed by Sound and Vision at:

    https://www.soundandvision.com/conte...-system-review


    My journey with the Modified CBT24 design is detailed at these two links:


    http://techtalk.parts-express.com/fo...new-cbt-arrays

    https://www.diyaudio.com/forums/full...ied-cbt24.html

    In the last link I have more discussion about living with my Modified CBT24s.

    To answer your concerns I would say that a CBT will sound more like Magnepan arrays than a box speaker but with improved side to side coverage. The sound is truly more life like in my opinion.

    Jim


    Last edited by Jim Griffin; 12-21-2018, 10:44 AM.

    Comment


    • #3
      Jim,

      Thanks for the response and info. I need to find a way to audition and hear for myself but I do have a couple more questions.

      1) How do the 36Ks differ from the 24Ks beyond the addition of the tweeters?

      2) Magnepans sound great. The imaging and sound stage is amazing but they are also kind of wimpy / light and airy..... even if you add a sub. For techno, rock and other music they do leave something to be desired. It sounds like the soundstage and imaging for the CBTs is amazing but is the sound light and airy as well?

      Comment


      • #4
        You clearly have a lot of experience with Magnepans so I can not match your listening insight. My experience with them has been limited to hearing them at equipment shows and in showroom situations. I was lucky enough to tour their White Bear Lake , MN plant several years ago so I appreciate how there are made and the technology behind them.

        My near field line array experience and the resultant arrays and experiences were an attempt to achieve stronger sound response than planar speakers can achieve. My more recent work and listening to CBTs have convinced me that while CBTs may not provide a higher overall SPL strength vs. a robust line array, they do provide an overall better sound experience than line arrays and planars can attain.

        While both the CBT36 and CBT24 variants can create great sound, the 24's are less complex (3 vs. 4 weight levels, fewer drivers, less crossover complexity (a 2-way vs. a 3-way)) when compared to the 36's. I've read some listeners comment that the small, in-efficient tweeters are a shortcoming for the CBT36 as they have low SPL ratings which need EQ'ing correction. Hence, a DSP processor will be needed for the CBTs. I play my Modified CBT24s with just Audyssey MultEQ correction from a typical home theater receiver.

        I would not say that the CBTs sound light and airy. They do things that planars and line arrays can not. The in-room sound of CBTs is superior in my opinion.

        Don Keele claims that CBTs have 3D sound radiation with constant beamwidth, constant directivity, constant coverage (near constant sound level from each side of the room), and constant radiated power (virtually the same in-room volume level front to back). They have a lot of bang for the buck.

        Comment


        • #5
          Jim,

          How will the 24ks do in a large room? Our great room (kitchen /dining room / living room) is approx 36x36 with 10’ ceilings.

          Comment


          • #6
            Alex,

            My living room where I have my Modified CBT24s is 34 feet long by 24 feet wide. The ceiling in my room is 10 feet high around the room but the center of the ceiling slopes upward to form an apex down the long dimension which is 18 feet high at the peak. The in-room sound is excellent as the arrays form an inherent ground plane with the floor. Furthermore, any ceiling bounces are mitigated by the design of the CBTs. The arrays are spaced away from the sides of the room--see photos at:

            https://photos.google.com/share/AF1Q...ZvRlBfdm5EbGdR

            Hence, any reflections from the sidewalls are far away and minimal.

            See my reply in post #4 above. You will hear exceptional sound anywhere within your room with near constant volume. CBTs are perfect for your application and for mine.

            Jim
            Last edited by Jim Griffin; 05-28-2019, 10:10 AM.

            Comment


            • #7
              Originally posted by Jim Griffin View Post
              Alex,

              My living room where I have my Modified CBT24s is 34 feet long by 24 feet wide. The ceiling in my room is 10 feet high around the room but the center of the ceiling slopes upward to form an apex down the long dimension which is 18 feet high at the peak. The in-room sound is excellent as the arrays form an inherent ground plane with the floor. Furthermore, any ceiling bounces are mitigated by the design of the CBTs. The arrays are spaced away from the sides of the room--see photos at:

              https://photos.google.com/share/AF1Q...ZvRlBfdm5EbGdR

              Hence, any reflections from the sidewalls are far away and minimal.

              See my reply in post #4 above. You will hear exceptional sound anywhere within your room with near constant volume. CBTs are perfect for your application and for mine.

              Jim
              great looking room!
              What got me, I have that same exact area rug, bought in germany in the 1980s....like what is the chance??

              Comment


              • #8
                Jim,

                Thanks for the quick response and for sharing the photos. Glad to know that you have a large space as eell
                and hey are working out great.

                1) what subs are you using?

                2) what size would you recommend for a large space, PE subs or another manufacturer?

                Alex

                Comment


                • #9
                  I am currently using a sealed/boosted 2 cubic feet volume sub which I designed a few years. The driver is an Eminence Lab 12 with a P-E subamp. My receiver has MultEQ room correction which sweetens the sound for my room.

                  In the planning stage I have an upgraded design that uses a buyout Thiel Audio 12 inch sub and a 1200 watts DSP sub amp (the Dayton Audio 300-8000 model). One of these days I hope to have two of these subs to cover my room. I prefer the sealed/boosted approach with some measure of DSP to best match the subs to the room. The Thiel drivers with a similar DSP amp were used in their $5000 subwoofer unit.

                  P-E has several woofers that can satisfy my needs and likely your requirement.

                  Jim

                  Comment


                  • #10
                    Just want to point out real quick to Alex that Jim is the guy when it comes to line arrays in listening rooms, a real trail blazer. I’ve read his white paper on line arrays from 2003 (linked here: https://audioroundtable.com/misc/nflawp.pdf ) many times. So his endorsement of the PE kit CBT arrays counts for plenty. - Thanks for the work you have done Jim.




                    That said, I have some thoughts to share based on my experience with a non standard CBT designs. I had the honor of listening to Kevin K’s CBT arrays at this years Lone star audio fest. http://techtalk.parts-express.com/fo...t-array/page13




                    While seated imagine was fixed about 2/3 of the way up the array, and very deep. Treble details seemed to hop between tweeter on the array, this may be a size issue with the spacing of these tweeters. Of course tone was dead nuts as Rick from Selah audio had assisted with the tuning of the mini DSP that was working crossover duty. I thought that the woofers were a hair large for the job, making the constant volume as you approach the array trick not as convincing as it might have been with drivers that were less directional. Floor bounce did not exist - similar effect to sitting near field with stand mounted speakers. Ceiling reflections were limited, and helped with some of the smearing you can get sometimes when using lots of drivers.




                    I’m very picky, it’s kind of my thing. Overall these are really good speakers, and by far the best speakers I’ve heard that use multiple tweeters.

                    Comment


                    • #11

                      A couple of comments on noaudiophile's reply. I comment on the performance of what I build and design as well as speakers that I hear at DIY meetings and such. I don't do endorsements per se so don't accept my comments on the CBT36 as an endorsement.

                      On ceiling reflections with a CBT the shading of the drivers effectively reduces the signal that impinges on the ceiling so I don't hear any impact on the sound heard in the room. It is not a question of smearing at all as the radiated sound is coherent in my opinion. I have yet to hear sound smearing from a CBT array. Don Keele has commented that a CBT produces no comb lining or smearing of the sound at 2 inches, 2 feet, 20 feet and so on from the array. Listen for that when you listen to a CBT.

                      Comment


                      • #12
                        CBT designs are the most unatural sounding speakers I have ever lustened to. I have yet to hear one pair I would own. They are dull, flat and lifeless. I don't care who, or how respected the designers, this design does not work for music. The CBT 36 demos were a joke. All you were listening to, I have heard the demo several times, were the sub woofers. I don't listen to car engines revving at 10000 rpms or sounds from of a racetrack. I listen to music. Which is something this design can not reproduce in a natural, musical sounding way. No amount of processing can fix all the issues in this design.
                        craigk

                        " Voicing is often the term used for band aids to cover for initial design/planning errors " - Pallas

                        Comment


                        • #13
                          Originally posted by craigk View Post
                          CBT designs are the most unatural sounding speakers I have ever lustened to. I have yet to hear one pair I would own. They are dull, flat and lifeless. I don't care who, or how respected the designers, this design does not work for music. The CBT 36 demos were a joke. All you were listening to, I have heard the demo several times, were the sub woofers. I don't listen to car engines revving at 10000 rpms or sounds from of a racetrack. I listen to music. Which is something this design can not reproduce in a natural, musical sounding way. No amount of processing can fix all the issues in this design.
                          I've never heard the CBT arrays, but this is exactly how I'd describe the sound from modern J array PA systems. There's just nothing there.

                          Comment


                          • #14
                            Craigk and civit,

                            Thanks for the additional feedback. It is very curious because there are a number of people that are raving about these speakers including a # of experienced DIYers. Also reviews on PE are very positive.

                            Do you really not like the sound or is this a “religious” or “camp” thing?

                            thanks

                            Comment


                            • #15
                              Originally posted by alexghanotakis View Post
                              Craigk and civit,

                              Thanks for the additional feedback. It is very curious because there are a number of people that are raving about these speakers including a # of experienced DIYers. Also reviews on PE are very positive.

                              Do you really not like the sound or is this a “religious” or “camp” thing?

                              thanks
                              When you are trying to get people to make a purchase you do not post poor reviews.

                              I am not a big line array fan in general. That being said, there are several line arrays I could live with. There is no CBT design I have listen to that I would bring home. I do not like the design. Like I stated above, this is the most unnatural sounding speaker I have heard.
                              craigk

                              " Voicing is often the term used for band aids to cover for initial design/planning errors " - Pallas

                              Comment

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