Announcement

Collapse
No announcement yet.

Planning - Ultimate high sensitivity 3-way; open baffle hybrid

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Planning - Ultimate high sensitivity 3-way; open baffle hybrid

    I'm planning the ultimate passive high sensitivity design. The woofer will be in a box and the mid-range will be open baffle. Similar to the Salk Archos or Dan's Basslines. I have attached two pics for understanding of my goal.

    Tweeter - Satori TW29RN (4ohm, 2.83V: 96 dB) or ???
    Mid-range - Acoustic Elegance TD6M (8ohm, 2.83V: 94.5 dB) or Dipole6 (8ohm, 2.83V: 91.4 dB )
    Woofer - Acoustic Elegance TD12X (4ohm, 2.83V: 99.7 dB) or TD12H (4ohm, 2.83V: 96.46 dB)
    Passive Radiator - Dual Dayton Reference 12" passive radiators (TD12X only)

    Basic design questions:
    Woofer sensitivity - The woofer will be similar to the Salk Archos and Dan's Basslines. When the woofer is low to the floor that means no baffle step compensation since the floor is basically the baffle right? What losses can I expect in regard to sensitivity?
    Mid-range sensitivity - My understanding is that the mid-range does not need to be as sensitive as the woofer. How much leeway is there?

    Driver questions:
    Tweeter - The Satori seems to have the highest sensitivity at the most reasonable price. THD at audioxpress looks just okay with only 0.5mm xmax. Other than that I only see the Transducer Labs N28BER-G and they are way too expensive! Any suggestions? I am open to domes, ribbons and planars.
    Mid-range - Does AE have 4ohm models of each? What are the advantages of the dipole version?
    Woofer - I assume that they are the same other than the voice-coil. Will the TD12X have any disadvantages in extension or box size with passive radiators?

    Thanks

    Click image for larger version  Name:	salk_archos.jpg Views:	1 Size:	53.3 KB ID:	1382407Click image for larger version  Name:	basslines2.jpg Views:	1 Size:	142.9 KB ID:	1382408

  • #2
    With the woofer you can/might expect a loss of output below the midband efficiency, since the sensitivity rating is not specific to the low corner. Calculate the EBP (Fs/Qes) so you can see where the sensitivity number manifests itself predominantly. Below that frequency, output will be governed by the alignment, as you cant expect to be 99 dB/1W/1m down to 20-30Hz for no effort what so ever. Have you actually modeled them to see what kind of bass extension you would be getting with the dual PR setup?
    Last edited by guitar maestro; 07-17-2018, 08:35 AM.

    Comment


    • #3
      Be aware of the difference in FR response of the open mid forward and backwards. It has to be compensated within crossover design.
      http://www.diy-ny.com/

      Comment


      • #4
        I won't be doing the crossover but I will hire someone else to do it for me. Several people have done that before. I'm just trying to pick the best drivers and balance for performance and high sensitivity. I'm leaning towards the TD12X with the Dayton Passive Radiators. I guess I could then get close to 95-97db 2.83V sensitivity. I'm just debating between the TD6M and Dipole 6.

        TD6M-8ohm
        Fs: 75.9Hz
        Qms: 3.97
        Vas: 9.2 L
        Cms: .4 mm/N
        Mms: 11 g
        Rms: 1.3 kg/S
        Xmax: 3 mm(peak)
        Xmech: 6 mm(peak)
        Sd: 127 sqcm
        Vd: 0.04L (p-p)
        Qes: .29
        Re: 6.2 ohm
        Le: .15 mH
        Z: 8 ohm
        Bl: 10.6 T/m
        Pe: 200W (cont.)
        Qts: .27
        1WSPL: 93.4 dB
        2.83V: 94.5 dB

        Dipole6-8ohm
        Fs: 79.08 Hz
        Qms: 11.71
        Vas: 10.26 L
        Cms: 0.45 mm/N
        Mms: 9 g
        Rms: 0.38 kg/S
        Xmax: 3 mm(peak)
        Xmech: 8 mm(peak)
        Sd: 126.7 sqcm
        Vd: 0.04L (p-p)
        Qes: 0.77
        Re: 6 ohm
        Le: 0.09 mH
        Z: 8 ohm
        Bl: 5.9 T/m
        Pe: 50W (cont.)
        Qts: 0.72
        1WSPL: 90.2 dB
        2.83V: 91.4 dB

        Comment


        • #5
          Note for constant directivity and with the larger mid, you will need a narrow baffle width so you can cross to the tweeter below the dipole null.
          John H

          Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

          Comment


          • #6
            Originally posted by Krillin View Post
            I won't be doing the crossover but I will hire someone else to do it for me. Several people have done that before. I'm just trying to pick the best drivers and balance for performance and high sensitivity. I'm leaning towards the TD12X with the Dayton Passive Radiators. I guess I could then get close to 95-97db 2.83V sensitivity. I'm just debating between the TD6M and Dipole 6.

            TD6M-8ohm
            Fs: 75.9Hz
            Qms: 3.97
            Vas: 9.2 L
            Cms: .4 mm/N
            Mms: 11 g
            Rms: 1.3 kg/S
            Xmax: 3 mm(peak)
            Xmech: 6 mm(peak)
            Sd: 127 sqcm
            Vd: 0.04L (p-p)
            Qes: .29
            Re: 6.2 ohm
            Le: .15 mH
            Z: 8 ohm
            Bl: 10.6 T/m
            Pe: 200W (cont.)
            Qts: .27
            1WSPL: 93.4 dB
            2.83V: 94.5 dB

            Dipole6-8ohm
            Fs: 79.08 Hz
            Qms: 11.71
            Vas: 10.26 L
            Cms: 0.45 mm/N
            Mms: 9 g
            Rms: 0.38 kg/S
            Xmax: 3 mm(peak)
            Xmech: 8 mm(peak)
            Sd: 126.7 sqcm
            Vd: 0.04L (p-p)
            Qes: 0.77
            Re: 6 ohm
            Le: 0.09 mH
            Z: 8 ohm
            Bl: 5.9 T/m
            Pe: 50W (cont.)
            Qts: 0.72
            1WSPL: 90.2 dB
            2.83V: 91.4 dB
            If you're really running "dipole" that means you are in the region below beaming, or in the baffle step region and no higher. In that case, driver sensitivity is dropping at a 1st order rate, or 6dB per octave for an open baffle design. Your mid will need to be much higher sensitivity than the woofer in that case.
            R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

            Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


            95% of Climate Models Agree: The Observations Must be Wrong
            "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

            Comment


            • #7
              I honestly thought I would be gaining sensitivity in the mid-range and not losing it. Therefore I was only really concerned with the woofer. Bummer...I thought I read a comment somewhere that Jeff B. in the Archos found the mid-range 3db more sensitive than he thought it would be. Something about gain coming from the rear increased the power response.

              That only really leaves the Dayton PM180-8 in MTM format. Although cosmetically not what I was shooting for the performance should be there.

              Edit: Found it in post #8 "When I did the Salksound Archos which used an open baffle PHL midrange I found I needed to lower the midrange level about 3dB more than I anticipated based on using the same driver in the Salk Pharos. The gain is coming from the rear energy contributing to the drivers power response." -Jeff B.
              http://techtalk.parts-express.com/fo...itivity-output

              Comment


              • #8
                I don't have any input, but would just like to comment that I admire you for taking on such an ambitious project. A passive dipole is a big challenge, a HE design isn't easy either, but a passive high efficiency dipole is a really cool thing to pull off.

                Good high efficiency midranges are hard to come by. Have you considered the Audax model sold by those guys in Wisconsin?

                Comment


                • #9
                  it seems as though someone would feel the need to produce a high quality high efficiency midrange . some have attempted but either the quality or efficiency is just not quite what you need . the Dayton PM180 does come highly recommended . other than the PM180 and AE you will have to look at pro audio offerings , pro audio is starting to show up more now in home audio for this very reason . once you find that high efficiency midrange , will it work for your application ?
                  donc
                  Last edited by donc; 07-17-2018, 10:04 PM.

                  Comment


                  • #10
                    Krillin, PM sent.

                    Comment


                    • #11
                      Originally posted by Krillin View Post
                      I honestly thought I would be gaining sensitivity in the mid-range and not losing it. Therefore I was only really concerned with the woofer. Bummer...I thought I read a comment somewhere that Jeff B. in the Archos found the mid-range 3db more sensitive than he thought it would be. Something about gain coming from the rear increased the power response.

                      That only really leaves the Dayton PM180-8 in MTM format. Although cosmetically not what I was shooting for the performance should be there.

                      Edit: Found it in post #8 "When I did the Salksound Archos which used an open baffle PHL midrange I found I needed to lower the midrange level about 3dB more than I anticipated based on using the same driver in the Salk Pharos. The gain is coming from the rear energy contributing to the drivers power response." -Jeff B.
                      http://techtalk.parts-express.com/fo...itivity-output
                      There are several fullrange drivers, that would make great mids, efficient enough to do whst you need.
                      craigk

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

                      Comment


                      • #12
                        I've considered the pro offerings and Audax.

                        Audax - very high sensitivity but a ragged top end and I'm not sure that the motor design would compare with the top offerings from other major manufacturers. The plan is to top the Archos, not match it.
                        Pro offerings - They definitely have the sensitivity but the square frames, 10db swings in the frequency response, and lack of measurement comparisons make me wary.

                        So far the AE TD6M (especially if they make a 4ohm version), Dayton PM180-8 or the PS180 looks the most useful. The more I look it appears difficult to outdo the Basslines with the B&C 6MD38.

                        If Dan N. or Jeff B. read this how much losses did you incur with the PHL 1120 or B&C 6MD38 mid-range?

                        Comment


                        • #13
                          You can model the pseudo response on baffle with ABC dipole. I can shoot you a quick graph later tonight.
                          John H

                          Synergy Horn, SLS-85, BMR-3L, Mini-TL, BR-2, Titan OB, B452, Udique, Vultus, Latus1, Seriatim, Aperivox,Pencil Tower

                          Comment


                          • #14
                            Thanks jhollander

                            I reached out to John and apparently there isn't enough demand to justify a purchase of parts for 4-ohm versions.As this is just the planning phase I'll think on the MTM PM180 or AE TD6M/8M option for a while.

                            Changing the topic, has anyone found a fix to run Bagby's "Woofer Box and Circuit Designer 5" on a 64-bit version of office? I used it years ago and it was the most intuitive program that I found.

                            Comment


                            • #15
                              The Eminence Alpha-6c has an impressively flat looking graph for a pro speaker. Same with the FaitalPro 5FE120, if it is sensitive enough for you. You could possibly double up on the mid-range drivers if they are too quiet. Both could even possibly be run wide open, without a crossover, for more efficiency. The PM180 would seem ideal also, I have heard the PM220 and I think it sounds very good.

                              One of the great things about open baffle is that it is easy to mock up a quick test baffle to evaluate drivers.

                              Comment

                              Working...
                              X