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How to Train Your PM180-8

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  • #61
    Re: How to Train Your PM180-8

    Originally posted by johnnyrichards View Post
    It isn't debatable, if it were - we would all be using cheaper drivers.
    Unless every person on earth can hear the difference between a system using a driver with a -40db distortion peak at 3.5Khz and one with no peak regardless of how the driver is used, it's debatable. I (and probably most on this forum) have heard speakers with relatively high distortion that sounded good and some with extremely low distortion that sounded horrible.

    Overall, I think these mods will prove to be significant improvements when the driver is used competently.
    Last edited by czag; 06-15-2015, 12:27 AM.
    Chris

    Goofing around since 2000.

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    • #62
      Re: How to Train Your PM180-8

      Dayton's impedance curve shows ripples around 100 Hz and as expected at the breakup
      frequency. Did you also see the 100 Hz ripple? Just wondering if it is measurement noise
      since I can't think of a good reason for it:
      http://www.parts-express.com/pedocs/...ifications.pdf

      Wish there was a higher efficiency version with shorter throw for midrange applications.

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      • #63
        Re: How to Train Your PM180-8

        Originally posted by Pete Basel View Post
        Dayton's impedance curve shows ripples around 100 Hz and as expected at the breakup
        frequency. Did you also see the 100 Hz ripple? Just wondering if it is measurement noise
        since I can't think of a good reason for it:
        http://www.parts-express.com/pedocs/...ifications.pdf

        Wish there was a higher efficiency version with shorter throw for midrange applications.
        Here's our actual measurement of the PM180 in the enclosure.

        Click image for larger version

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        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.

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        • #64
          Re: How to Train Your PM180-8

          Originally posted by Pete Basel View Post
          Dayton's impedance curve shows ripples around 100 Hz and as expected at the breakup
          frequency. Did you also see the 100 Hz ripple?
          It's probably because they used a WT3

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          • #65
            Re: How to Train Your PM180-8

            I got a pair of PM220 in the mail today, just thought I'd post some thoughts here. I must say that I absolutely do not like the sticky ring on the surround. I have no idea how PE took such a clean picture of these drivers. They came covered in cardboard dust from their own packaging, there's really no way for these to ever look completely clean, as they'll cling to any dust in the air. I'll be spending some time on each driver with a pair of tweezers to try and clean them up. Other than that I can say that the suspension is very low loss, and I'm surprised how thin the cone is. This is a very fragile speaker, probably not a good choice anywhere near children.
            "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
            exactly a Fc 3K for both drivers, anybody can do it." -Xmax

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            • #66
              Re: How to Train Your PM180-8

              I use blue painters masking tape to clean my sticky surrounds on vintage drivers since it seem to be tacky enough to pull the fluffies loose without ripping the surround. Avoid solvents although I have used denatured alcohol on 50 year old drivers with extreme stuff stuck to them.
              Last edited by fdieck; 06-18-2015, 12:25 AM.

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              • #67
                Re: How to Train Your PM180-8

                I'll give it a shot, thanks for the tip.
                "I just use off the shelf textbook filters designed for a resistor of 8 ohms with
                exactly a Fc 3K for both drivers, anybody can do it." -Xmax

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                • #68
                  Just found this. Oldie but goodie, especially the Scan Speek thread referenced in first post...

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                  • #69
                    These sounds fantastic in the vapor audio speakers...

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                    • #70
                      Jbruner, have you seen Troels' latest piece on using surround treatment with glue? Could be a clue to a less destructive method to get similar results...

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                      • #71
                        I had hoped that Pete or Ryan would update this thread, but I guess it's up to me to tell what happened. Upon request, I sent the original drivers from this thread to Ryan at Vapor Audio. That was early July, 2015. No response. In January 2016, I attempted to contact him. I got thru to him in February and told him I wanted to pass the sliced pair on to someone else, He said they were in the Derecho, and he wanted to keep them. He said he was planning on a full write-up, which tragically never happened. He did send me replacement drivers.

                        In the next few years, I saw sporadic glimpses on the internet of the sliced drivers at some industry shows. Apparently they were very well received. Just this year, I reached Ryan by phone and got permission to post this update.

                        The sliced PM180s are still in service in Ryan's Derecho speakers. He likes the improvements and said there is no downside. Without putting words in his mouth, here's a quote from Ryan on the internet. "The Derecho have the same midrange, but with the sliced cone process applied that totally transforms and greatly refines the presentation. It was a DIY'er, Josh Bruner, who created and perfected the process. When we got our hands on a pair, we decided to make them the standard midrange. It's a small improvement on paper that results in a large improvement in the real world." I also noticed that Pete S. praised the modified drivers in another thread, but never came back here to reveal his changed opinion.

                        So, I'm back here to say that the process works, and is long-term durable. I have some sliced drivers that have been in service for 6 years. I've already presented the science, so I'll just give my opinion now. The results are MAGICAL. No other driver modification is this effective or this important. This process will transform many drivers into the proper midranges that you always wished they were.

                        Here's a pic of the Derecho I cribbed from the web. Click image for larger version

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                        "Looks like you may have to design your own speakers. Its not that hard." -DE Focht

                        Diffraction Happens

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                        • #72
                          I heard the ply-stacked Derecho version on the banner at AXPONA that year, and I really liked them! Smooth, easy, and dynamic; they are a special build.

                          Good to see you are still around, Josh!
                          Wolf
                          "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                          "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                          "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                          "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                          *InDIYana event website*

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                          My blog/writeups/thoughts here at PE:
                          http://techtalk.parts-express.com/blog.php?u=4102

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                          • #73
                            I used the slicing technique on some Eminence alpha 6C drivers that I bought for the car. It worked well and allowed me to run the drivers without a low pass filter. Should have the measurements somewhere...

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                            • jbruner
                              jbruner commented
                              Editing a comment
                              I would love to see your results!

                          • #74
                            Originally posted by Wolf View Post
                            I heard the ply-stacked Derecho version on the banner at AXPONA that year, and I really liked them! Smooth, easy, and dynamic; they are a special build.

                            Good to see you are still around, Josh!
                            Wolf
                            Yeah, I'm certain it's a really nice speaker now! Good to see the old people still around! Enjoyed meeting you a few years ago!
                            "Looks like you may have to design your own speakers. Its not that hard." -DE Focht

                            Diffraction Happens

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                            • #75
                              Originally posted by jbruner View Post

                              Yeah, I'm certain it's a really nice speaker now! Good to see the old people still around! Enjoyed meeting you a few years ago!
                              They have been Ryan's main speakers since the day we finished them. Still occupy his main listening room today. Your mod is utterly transformative and should be incorporated at the factory.
                              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.

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