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Some good info...!

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  • Some good info...!

    Found this site, it is a bit basic, but still quite useful. A lot of information.


    http://audiojudgement.com/index/
    Last edited by kevintomb; 09-27-2017, 06:29 AM.

  • #2
    What site?

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    • #3
      This site, of course ;)
      Don't waste your money on a new set of speakers, you get more mileage from a cheap pair of sneakers. Next phase, new wave, dance craze, anyways it's still rock and roll to me!

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      • #4
        I can't see it. It must be like the Emperor's New Clothes, and I'm unfit :(
        Francis

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        • #5
          You certainly do have a sense of humor!

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          • #6
            Maybe http://www.bose.com

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            • #7
              http://audiojudgement.com/index/

              Wow, sorry not sure what happened!

              http://audiojudgement.com/

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              • #8
                Out of curiosity I read part of the section about transmission lines, and it's so full of inaccuracies, downright lies and BS, it's laughable. After about 3 paragraphs I gave up.
                Paul

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                • #9
                  Originally posted by Paul K. View Post
                  Out of curiosity I read part of the section about transmission lines, and it's so full of inaccuracies, downright lies and BS, it's laughable. After about 3 paragraphs I gave up.
                  Paul


                  Ugh...really?? I read a few parts and found some good info, did not read it all....


                  He does refer the book he took most of his info from, so I assumed it was mostly accurate

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                  • #10
                    Originally posted by Paul K. View Post
                    Out of curiosity I read part of the section about transmission lines, and it's so full of inaccuracies, downright lies and BS, it's laughable.
                    I disagree, it's pretty accurate as far as pure TLs go, other than not taking into account any T/S specs. It doesn't consider mass loaded TLs, but that particular horse is of a different color anyway. I do see numerous errors, for instance the explanation of how damping functions, in not only TLs but also in sealed boxes, but they're errors that exist in the source materials he used. It appears that the author's experience is less hands-on than just copied and pasted from other sources. If those sources got it wrong then so did the author. What's really curious is his use of formulas in cab design instead of software. That alone puts him 20 years or more behind the curve.

                    www.billfitzmaurice.com
                    www.billfitzmaurice.info/forum

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                    • #11
                      The first paragraph states that there is no reliable software to model the enclosure results in an accurate fashion. So what about software from Martin King, George Augsperger and Leonard Audio? Then its stated, in so many words, that knowing where to place damping material (the line stuffing) is hard to predict. That's one of the many things the modeling software let's you determine. Then, it's stated that only by trial and error can one make a good transmission line speaker. That's what the modeling software eliminates, trial and error. Moving on to the step-by-step recommended design process, it's stated that you make the length of the line such that its 1/4-wavelength resonant frequency equals the driver's fs. That's only true if the driver's Qts is close or equal to 0.4. If Qts is more than a little bit higher (or lower) than 0.4, the line's 1/4-wave resonance needs to be lower (or higher) than fs. When damping materials are discussed in detail, a table is shown that's clearly from George Augsperger's work, so why didn't this author know about George's software? Also, it's stated that long-fiber wool and Acousta Stuf are better than polyester fiber and fiberglass for damping. That's also not true, although as that table showed, it takes different stuffing densities from the materials to achieve similar results. All of the examples showing a driver in a TL show them with the driver mounted at the very beginning of the line. Unless it's a subwoofer that's crossed low, like 100 Hz, that's a poor-performing location. He concludes with this: The transmission line speaker design is definitely something that is more on the exotic side. Pretty difficult to design, to build and with no guarantees for the end result. Other than being a bit more complicated to build a folded line, that's BS. At the very end the only listed reference is the 7th Edition of Vance Dickason's Loudspeaker Design Cookbook, and as Bill mentioned it appears rather clearly that this author, Marius Tanasescu, just copied what Vance had used without any further checking. There are also a couple of emails to Marius with his replies, and it's clear to me that Marius did no personal research on the availability of accurate software for modeling TLs and is living in the past.
                      Paul



                      In the first it's stated that there is no reliable software to

                      Originally posted by kevintomb View Post



                      Ugh...really?? I read a few parts and found some good info, did not read it all....


                      He does refer the book he took most of his info from, so I assumed it was mostly accurate

                      Comment


                      • #12
                        Originally posted by Paul K. View Post
                        The first paragraph states that there is no reliable software to model the enclosure results in an accurate fashion. So what about software from Martin King, George Augsperger and Leonard Audio?
                        Look at the date of his source material. I would imagine when Vance wrote that, probably well before 2005, he was merely paraphrasing from Bailey and Bradbury, so now we're back to the 1970s. Marius strikes me as being sincere, but sadly out of date, and most likely unaware that's the case. He even still uses ported box alignments; I haven't since Bullock on Boxes was my guide.
                        www.billfitzmaurice.com
                        www.billfitzmaurice.info/forum

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                        • #13
                          You are correct, of course Bill, that the original source is outdated, but that doesn't excuse Marius from not doing far better research, especially since all of this under his name was created (copied) in 2016. Further, if you go to the very bottom of his TL Section and read his replies to the second of two emails others sent him, he reinforces the incorrect assumptions that stuffing in a TL significantly slows down the speed of sound while apparently dismissing the existence of Martin King's TL modeling software the emailer mentioned, even though the very beginning of his Section on TLs states there is no available software that can accurately model a TL. (Martin's TL experiments clearly showed there was no change in the frequency of the 1/4-wavelength resonance in a TL from no stuffing through three increasing stuffing densities.) And, Marius had the audacity to conclude his reply with this: Designing a TL might sound easy on paper, but when actually building one, you will encounter some difficulty, because they are very unpredictable. Any sincerity on Marius' part doesn't excuse his sloppy/lazy research.
                          Paul



                          Originally posted by billfitzmaurice View Post
                          Look at the date of his source material. I would imagine when Vance wrote that, probably well before 2005, he was merely paraphrasing from Bailey and Bradbury, so now we're back to the 1970s. Marius strikes me as being sincere, but sadly out of date, and most likely unaware that's the case. He even still uses ported box alignments; I haven't since Bullock on Boxes was my guide.

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                          • #14
                            Augsperger debunked the speed of sound being significantly slowed by stuffing some 15 years ago. Yes, Marius is incorrect on many counts, mostly because he's quoting outdated sources. A lot hasn't changed in the last 15 years, or for that matter the last 50, but a lot has.

                            www.billfitzmaurice.com
                            www.billfitzmaurice.info/forum

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