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How to Train Your PM180-8

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  • Wushuliu
    replied
    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...

    Leave a comment:


  • ani_101
    replied
    These sounds fantastic in the vapor audio speakers...

    Leave a comment:


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

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  • dcibel
    replied
    Re: How to Train Your PM180-8

    I'll give it a shot, thanks for the tip.

    Leave a comment:


  • fdieck
    replied
    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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  • dcibel
    replied
    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.

    Leave a comment:


  • fatmarley
    replied
    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

    Leave a comment:


  • Pete Schumacher
    replied
    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

Name:	PM180ZMA.gif
Views:	1
Size:	19.1 KB
ID:	1167050

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  • Pete Basel
    replied
    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.

    Leave a comment:


  • czag
    replied
    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.

    Leave a comment:


  • dcibel
    replied
    Re: How to Train Your PM180-8

    No problem Jeff, I understand. I have a pair of the PM220 en-route to me, so I'm just trying to get as much info on them as possible. I guess I'll find out when they get here, but I'm just trying to decide if I should be looking at a 3-way design instead of my original 2-way plan using a Wavecor TW030WA12 which is an above normal size tweeter with a small waveguide.

    Leave a comment:


  • Jeff B.
    replied
    Re: How to Train Your PM180-8

    Originally posted by dcibel View Post
    Thanks for that insight, even if you're not responding to my posts.
    Sorry, no offense intended. I'm just hit and miss on here sometimes. I don't always keep up with the everything.

    Leave a comment:


  • dcibel
    replied
    Re: How to Train Your PM180-8

    Originally posted by Jeff B. View Post
    From my measurements it goes wickedly chaotic at just over 1 khz with wide-bandwidth 25 dB swings to deal with. It's not that it's unusable, but it requires some steep slopes to make work. I've worked with some B&C and Eminence 8" drivers that have a very smooth and extended bandwidth by comparison. The offer a lot more flexibility.
    Thanks for that insight, even if you're not responding to my posts.

    Leave a comment:


  • Jeff B.
    replied
    Re: How to Train Your PM180-8

    Originally posted by Rory Buszka View Post
    If anything were done to improve the PS180 and PM180, it would be to adjust the weight percentage of Kevlar fiber in the cone (to keep it light but make it less stiff = less ringing) and apply a damping coating to the back side, maybe only from a starting point of 1/2 the outside radius to the outside edge. Slicing the paper cone either requires die-cutting tooling or would be labor-intensive. I see no reason to modify the dust cap or even the open pole piece, however a copper-anodized aluminum plug that is just tall enough to fill the gap would look cool if visible thru the dust cap. However, I don't really predict anything will be done to that driver. If were still in that chair, I'd let it go as-is. It's a niche driver so sales are likely to remain small even with changes.
    There's probably a list of things that can be done for any driver, which in the end turns it into another driver. However, I think the PM-180 has its place when used as a midrange and does an excellent job. I have used it in a very high-end design for someone, and I am looking at it right now for use in another three-way.

    I do wish you guys had done a bit more to tame the PM-220 though. From my measurements it goes wickedly chaotic at just over 1 khz with wide-bandwidth 25 dB swings to deal with. It's not that it's unusable, but it requires some steep slopes to make work. I've worked with some B&C and Eminence 8" drivers that have a very smooth and extended bandwidth by comparison. The offer a lot more flexibility.

    Leave a comment:


  • Rory Buszka
    replied
    Re: How to Train Your PM180-8

    If anything were done to improve the PS180 and PM180, it would be to adjust the weight percentage of Kevlar fiber in the cone (to keep it light but make it less stiff = less ringing) and apply a damping coating to the back side, maybe only from a starting point of 1/2 the outside radius to the outside edge. Slicing the paper cone either requires die-cutting tooling or would be labor-intensive. I see no reason to modify the dust cap or even the open pole piece, however a copper-anodized aluminum plug that is just tall enough to fill the gap would look cool if visible thru the dust cap. However, I don't really predict anything will be done to that driver. If were still in that chair, I'd let it go as-is. It's a niche driver so sales are likely to remain small even with changes.

    Leave a comment:

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