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  • Originally posted by Peter van Gils View Post

    Stef, I can bring you in contact with Christian (from Germany) if you like. Christian built the PM90 with the ND950. Send me a PM.

    I think Peter Morris used the 12NW76 (or was it the 12NDL76?) in one of his builds, but he liked the RCF more.


    Sent from my iPhone using Tapatalk
    I used the 12NDL76 in my 60 degree boxes, its a little difficult to compare as my 60 degree boxes have a slightly longer mid horn than the original PM90's. This was to accommodate the extra length of the XT1464 horn compared to the HF950.

    The longer mid horn in the PM60s works slightly better but I suspect the RCF is a slightly better driver in this application.

    Comment


    • Originally posted by Stef Smits View Post
      Does anybody have any experience with the RCF ND950 1.4 compression driver?
      I've read an article about a German company that build the PM90 with the ND950.
      I also thought RCF used the ND950 in the newer ART745A from 650 Hz and up.
      I'm aware that the ND950 can be fully used from 800 Hz, but I am curious of it will go a bit lower.

      Also would the B&C 12NW76 be suited driver for the low/mid?

      Thanks for any info!
      AFAIK, RCF use the HF950 horn in their new TT5A and TT2A. The TT5A uses the ND950 compression driver and the TT2A uses ND850.

      The TT5A crossover is 650Hz, the TT2a is 750Hz.

      The ART745A uses the ND940.

      I own some TT2A's and they are excellent, very natural sounding. When you compare these to the PM90 using the BMS4594HE you immediately notice how pristine the PM90's VHF is compared to the RCF. The PM90s sound noticeably better. It would be interesting to compare how the two compare at high SPL levels in the field.

      http://www.audioxpress.com/article/T...and-HF950-Horn

      Comment


      • Thanks for the reply!

        I think I'm going to sell the B&C's and buy some RCF's for the low/mid section.

        I'm very curious how the ND950 will perform in de PM90.

        Comment


        • Originally posted by Stef Smits View Post
          Thanks for the reply!

          I think I'm going to sell the B&C's and buy some RCF's for the low/mid section.

          I'm very curious how the ND950 will perform in de PM90.
          I think you will find only a very small difference between the B&C and RCF 12" drivers. I'm not sure you will notice much of a difference.

          Also if you try the ND950 its diameter is slightly bigger - 146mm Vs 133mm, so make sure it will still fit.

          Comment


          • The B&C driver I have is the 12nw76 not the 12ndl76.
            The nw has a higher xmax (8mm) and a bit lower qts value.

            I also had a reply from Christian who build the pm90 with the nd950. De rcf was up for the job and was able to play from 600 Hz. I think I will cross it a bit higher, just to ve safe.

            Comment


            • Originally posted by Stef Smits View Post
              The B&C driver I have is the 12nw76 not the 12ndl76.
              The nw has a higher xmax (8mm) and a bit lower qts value.

              I also had a reply from Christian who build the pm90 with the nd950. De rcf was up for the job and was able to play from 600 Hz. I think I will cross it a bit higher, just to ve safe.
              I think 600 Hz is getting a bit low for that driver on the HF950 horn ... The HF950 has a cut off frequency of 400Hz and you are getting close. I do not have any figures on the acoustic impedance of the horn, but I suspect RCF knows exactly whats appropriate and they cross that driver & horn at 650Hz in the TT5A.

              The 12NW76 will work but the response is getting a bit too uneven on the sim ... you could try it.


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              • I'm going to play safe, and buy some MB12N351's.

                Ps: the ND950 will fit in the original plan.
                Are there any descent schematic's available?

                Comment


                • Originally posted by Stef Smits View Post
                  Are there any descent schematic's available?
                  Something I had wondered as well, if you read back though the thread somebody was working on accurate plans, in any case I know Peter has also earlier in the thread given pretty good info to where certain panels come together in the box and there distant from external walls etc. Shouldn't be too hard to piece it all together from those details if one must.

                  Comment


                  • Originally posted by Jim dee View Post

                    Something I had wondered as well, if you read back though the thread somebody was working on accurate plans, in any case I know Peter has also earlier in the thread given pretty good info to where certain panels come together in the box and there distant from external walls etc. Shouldn't be too hard to piece it all together from those details if one must.
                    Still working on a good set of drawings for the 60deg version. I have most of it drawn, but not a published pdf yet. There's no reason to change them for the 90deg version unless you desperately need 1kg less weight per box. For the record - there's no good way to build the back corners without some excellent and very expensive CNC, Peter's method of cutting it off after the fact remains the best way I've found.
                    -MAX WARASILA

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                    • Been doing some measurements with my new Audiometica Clio Pocket set, and did some intense listen and measuring at different levels in a very big room.
                      I came to the conclusion that I got a better result moving the microphone around to different listening positions in the room to hunt those 'nasty' frequencies that doesn't show at on-axis 1 meter distance measurements.
                      Peaks was gently pulled down as discovered, resulting in quite a few eq's :0)

                      I have done two teatre jobs and a demo with 12x18" Bandpass with 20Kw amps and the output was crazy :0) Only signal lamps on my amps was lighting up. The headroom is enormous.
                      One of the very good things about this box is it's long throw properties without loosing low mid substance. Voices, toms and snare keep sounding 'full' at greater distances.

                      If you like, I will share the export (OQP) file from Powersoft. Could be fun to compare ;0)

                      Enclosed is an example of my method: (MH90_freq_resp_red is raw. Green is after eq. Yellow is 25degr 2m. Black is 25degr 4m after eq) The final measurment is not included thus not corresponding to the eq settings further down in this post.

                      Click image for larger version

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                      LOW eq on Powersoft K series.

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                      Hi eq on Powersoft K series:

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                      " location w/o front foam.

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                      Attached Files

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                      • Originally posted by Peter Morris View Post
                        I think 600 Hz is getting a bit low for that driver on the HF950 horn ... The HF950 has a cut off frequency of 400Hz and you are getting close. I do not have any figures on the acoustic impedance of the horn, but I suspect RCF knows exactly whats appropriate and they cross that driver & horn at 650Hz in the TT5A.
                        If you need a lower cutoff you could always try our new DE1090TN, a 4" diaphragm on a 1.4" throat - also not expensive or heavy.

                        http://www.bcspeakers.com/products/h...1-4/8/de1090tn
                        -- Bennett Prescott
                        Sales & Operations Manager - North America
                        B&C Speakers NA, LLC
                        Office: (973) 248-0955
                        Cell: (518) 488-7190

                        Comment


                        • Originally posted by Bennett Prescott View Post

                          If you need a lower cutoff you could always try our new DE1090TN, a 4" diaphragm on a 1.4" throat - also not expensive or heavy.

                          http://www.bcspeakers.com/products/h...1-4/8/de1090tn
                          Hi Bennett,

                          The DE1090TN looks very interesting and I would love to try some. In this case the cut-off frequency I was referring to was the horn flare.

                          FWIW I'm crossing my 90 degree boxes at 700Hz and the 60 degree boxes at 650Hz.

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