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Philips 10100-8 10" woofer replacement in Transmission Line cabinets

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  • Frub
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    Originally posted by fpitas View Post
    That's a bit harsh. Engineering, like all science, progresses with time. Many famous and unquestionably talented engineers and scientists had their share of erroneous beliefs and conclusions, it's just part of the process.

    Francis
    True...
    Last edited by Frub; 02-21-2015, 09:58 PM.

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  • Frub
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    Originally posted by martin View Post
    What does it take to show a robust TL design methodology?

    Answer, start with a given driver and design the TL geometry and stuffing placement. Based on the design, calculate predictions for the electrical impedance, driver SPL response, terminus SPL response, and combined system SPL response for both the empty and stuffed TL. Build the TL system and measure the empty and stuffed electrical impedance and SPL output results. Plot the predicted responses and measured responses on the same graph to demonstrate that the procedure correlates. Show this for a variety of other designs to show the calculation method is robust and not just a single point success. Now you have shown that you totally understand how a TL works and can program that knowledge and produce a reliable design tool.

    Examples :

    MJK's MathCad worksheets - completely verified by many users.

    George Augspurger's TL software - completely verified by many users.

    HornResp - partially verified.

    Leonard Audio TL Software - partially verified.

    Bailey and Bradbury Articles - no valid software or correlation of method (Bullock and MJK both tried but were not successful)

    Repeated reference to a set of 40+ year old articles is just not very interesting. If you have the data to show a robust TL design methodology based on these papers, as defined above, then that is of great interest. Anything short of that is just not a credible discussion in my opinion; I am not interested in going down that path again for the umpteenth time.
    Who is it that is referencing 40+ year old articles? Stuffing? Should it be synthetic or long fiber wool? How do you prepare the stuffing? It makes a difference... Yes there were the Bailey and Bradbury articles, but the origins of the transmission line design predates those articles to sometime in the 50's. But, even so, they weren't just flying by the seats of their pants; they were already taking impedance measurements. Transmission lines weren't a gimmick, they did evolve. There was a method to the madness or they would have died off. People could already hear that they worked better than sealed and ported designs. There was obviously something valid about the design that influenced you, or why would you bother to put it to numbers. What you heard clearly influenced your thinking. Bailey and others would be thanking you for continuing their work. No surprise that Bailey didn't have access to valid software, or even a smart phone. It was a different time. It would be like dismissing the early designers of computers because they used valves instead of solid state.

    In addition to building two lines using your math I also built an Augspurger designed line that came to 8' and made provision for lengthening the line, it sounded great. I added an extra two feet and it sounded better. My experience is the longer the line the more subtle it is, more like a good concert hall. How is that measured? How do we know if we ever have it right? What is our reference? How many people building transmission lines now days have ever built a 14' line and compared it. It's like photographers who have only ever used a digital camera criticizing film. Some people think the sound from sealed boxes is superior, others from planar speakers. They don't necessarily sound alike, but they both may measure well. What is the source material? Are we ever missing a parameter? For someone to say it sounds perfect, because the math is perfect is a stretch. If so, there would be a world of perfect speakers, all sounding alike.

    The early transmission line builders understood something and experimented with drivers and found those that worked. They knew that a line of a certain length worked with certain drivers, that small list of drivers was well documented, including the Philips in question. There was a time when someone could offer Mr. Keilau some help, but now there appears to be almost no one on this thread with that knowledge, most everyone being just a bit smug. Makes you wonder if anyone has ever built anything or just busy crunching numbers. I was able to offer him what I thought would might be an appropriate substitute, and then someone else kindly offered their help. Instead, Mr Leilau was baited into defending himself. Coming up with this list of drivers was a valid approach with the tools that the early TL designers had available to them. From there, they did do some reverse engineering. John Wright, according to IMF, specified certain parameters for the B139 used in some of his transmission lines. So, they already knew something. They were not just sitting on their hands. All B139's did not look alike, I've seen different magnet structures.

    Cheers...

    Leave a comment:


  • MSaturn
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    8/10 would read crazy old dude bizarro threads again

    Leave a comment:


  • djg
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    Originally posted by Frub View Post

    No, I built a couple new math lines. The math verified and double checked. They worked well enough, others thought so. I built still another new math line and gave it to a friend, he loved it. But, they had no other reference.
    Ignorant peasants wallowing in the mediocrity of your "new math" TLs. Jeez.

    Leave a comment:


  • isaeagle4031
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    Can you provide data that backs up Bailey's theory as correct? Can you say unequivocally that further work of Martin and others is incorrect? Time and time again, Martin's worksheets have proven accurate, much as the same as Jeff Bagby's PCD. The measurable conclusion is there unlike Baileys. What I have seen of the models of Bailey's work have not been and then numerous reasons why the model and application don't mesh.

    Leave a comment:


  • Frub
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    Originally posted by isaeagle4031 View Post
    I don't believe it's fair to call him a troll. He has said nothing but his own opinion. Let the discussion continue.
    Thanks...

    Leave a comment:


  • martin
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    What does it take to show a robust TL design methodology?

    Answer, start with a given driver and design the TL geometry and stuffing placement. Based on the design, calculate predictions for the electrical impedance, driver SPL response, terminus SPL response, and combined system SPL response for both the empty and stuffed TL. Build the TL system and measure the empty and stuffed electrical impedance and SPL output results. Plot the predicted responses and measured responses on the same graph to demonstrate that the procedure correlates. Show this for a variety of other designs to show the calculation method is robust and not just a single point success. Now you have shown that you totally understand how a TL works and can program that knowledge and produce a reliable design tool.

    Examples :

    MJK's MathCad worksheets - completely verified by many users.

    George Augspurger's TL software - completely verified by many users.

    HornResp - partially verified.

    Leonard Audio TL Software - partially verified.

    Bailey and Bradbury Articles - no valid software or correlation of method (Bullock and MJK both tried but were not successful)

    Repeated reference to a set of 40+ year old articles is just not very interesting. If you have the data to show a robust TL design methodology based on these papers, as defined above, then that is of great interest. Anything short of that is just not a credible discussion in my opinion; I am not interested in going down that path again for the umpteenth time.

    Leave a comment:


  • Frub
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    Originally posted by Paul K. View Post
    If you used the "new math" correctly to model TLs and you built exactly what you modeled, then you would have gotten good to excellent results, so apparently you didn't do one or both actions at all well. Also, what the heck are you talking about when you say only your long lines don't "hum" or don't make noise? None of my "new math" lines hum or make audible noise. That said, Bailey was a pioneer on TLs and nobody is simply dismissing his work, but times have changed and improvements in designing TLs are readily available leading to improved performance. You can choose to live in the past, of course.
    Paul
    Or build on the past and move into the future. If not for Bailey and others of his time we might not be where we are. It's not right to say Bailey was wrong. Like so many things someone has to first have the idea. Too many people are now acting like they came up with the idea. More so, Bailey's theory was correct and we're trying to improve on it.

    No, I built a couple new math lines. The math verified and double checked. They worked well enough, others thought so. I built still another new math line and gave it to a friend, he loved it. But, they had no other reference. I flip back and forth regularly; single drive, planars, sealed cabinets, transmission lines. Always trying to learn something. Assuming nothing.

    "So much time we spend in our education, in our lives is spent learning certitudes, learning habits, trying to fight against the unknown" Bertrand Piccard.

    I often wonder if Martin ever went back with one of his new math designs and compared it to the old math TL that so impressed him and spurred his interest in transmission lines.

    Leave a comment:


  • Paul K.
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    If you used the "new math" correctly to model TLs and you built exactly what you modeled, then you would have gotten good to excellent results, so apparently you didn't do one or both actions at all well. Also, what the heck are you talking about when you say only your long lines don't "hum" or don't make noise? None of my "new math" lines hum or make audible noise. That said, Bailey was a pioneer on TLs and nobody is simply dismissing his work, but times have changed and improvements in designing TLs are readily available leading to improved performance. You can choose to live in the past, of course.
    Paul

    Originally posted by Frub View Post
    I read nothing harsh. Too many people seem to get pleasure from taking a bite of Mr. Bailey. Remember he helped get us started and we are only building on his ideas. If Bailey were in our time with the idea and with the resources we have available you would be talking about him differently. People have been harsh with their criticisms toward Mr. Bailey, but we owe him. I've taken his ideas and built on them with longer lines and they work perfectly, no humming, no bottoming out, etc... I've built transmission lines using the new math and they have been a disaster. A close friend built two 14' lines with 24" Hartleys and they are magnificent. Seems like too many people want to dismiss Mr. Bailey and make the transmission line exclusive to this era. There are a enough young people floating around that think Steve Jobs invented the computer.

    Leave a comment:


  • Mike b
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    Originally posted by isaeagle4031 View Post
    I don't believe it's fair to call him a troll. He has said nothing but his own opinion. Let the discussion continue.
    Agree,and this has been a very informative discussion for me as well as entertaining

    Leave a comment:


  • isaeagle4031
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    I don't believe it's fair to call him a troll. He has said nothing but his own opinion. Let the discussion continue.

    Leave a comment:


  • fpitas
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    Originally posted by djg View Post
    New troll is more polite than the original troll.
    +1

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  • djg
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    New troll is more polite than the original troll.

    Leave a comment:


  • isaeagle4031
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    But the theory of the past was proven incorrect. Nothing against Bailey or any of the audio pioneers. We are thankful for their ideas and spirit. But just as in other areas we have advanced. Martin and others have developed the models that with accurate input have time and again to be correct. Why is this so hard to understand? The old is better because?????

    Leave a comment:


  • Frub
    replied
    Re: Philips 10100-8 10" woofer replacement in Transmission Line cabinets

    Originally posted by martin View Post
    I just looked back in my personal notes and found that I have been working on transmission lines for over 25 years. I have the articles you referenced and all the copies of Speakerbuilder. I analyzed many TL's using the methods in the referenced articles and compared the results against measured electrical impedance and SPL plots. The methods did not correlate, the calculated results based on these theories were wrong. I was not alone in this conclusion, check out the paper by Bullock and his experience with TL modeling.

    So I designed and built a test TL and took many careful measurements, revisited all of my equations and fixed the mistakes resulting from following the articles you provided. The biggest mistake is the belief that the fibers move and slow the speed of sound. This was a fundamental error made by Bailey and Bradford in their AES articles.

    At the same time I was formulating my models George Augspurger approached the problem with a different method of modeling and reached the same conclusions. Our two different calculation approaches produce the same answers for a given TL geometry. Both of us have produced excellent correlations between predictions and measured electrical impedance and SPL responses. Everything I have done is on my site for people to review and form an independent opinion. George Augspurger's work is presented in AES papers and in the Journal of the AES. Over the past 10 years many TL's have been designed by different users of my MathCad worksheets and after building them the measured results matched the predictions. Sounds pretty well wrapped up to me.

    Don't like or believe in the newer more modern TL design theory and want to stick with the work from the late 60's and early 70's is fine by me. Can you show calculated results with enough detail that they can be checked and then produce a build with measurements that correlate against the predictions? I can. Since I have not seen any real work from you in my opinion your posts do not carry a lot of weight. Bring something to the table for people to chew on, more then just words telling others with years of successful experiences that they are wrong. Not much point in continuing a one sided conversation. Your move.
    The fibers may not slow the speed of sound, but they do move.

    Leave a comment:

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