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KLH PR-950S - Replace drivers and crossover help

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  • KLH PR-950S - Replace drivers and crossover help

    Dear Forum,

    The KLH Model PR-950S' are an older low cost speaker from the early 90's (after KLH became a "cheap" brand - see specs at bottom). Saving my hard-earned grass cutting money, I purchased these speakers when I was only 14 years old believing these were the "renowned" KLH I heard about from friends of yore. I always loved them for the warm sound they produced but as a (much) older adult returning from overseas, I pulled these from storage to see if they still sound bellissimo to my ears. Pairing these with a modern Pioneer Elite SC-85 AVR, I am largely and predictably disappointed.

    Herein lies the purpose of this posting. Before I invest the time in either building costly speakers or purchase the units I so desire (Magnepan 1.7s), I wish to explore the possibility of a) replacing the drivers and crossover in the existing cabinet which is ported and without any internal bracing/separation or b) crossover to the 15" woofer bypassing the terrible 5 1/4", 4", and 1 inch "super-tweeter" and place a mid-bass/tweeter 2-way cabinet on top (a satellite so to speak). The 15" still sounds warm and provides a "big" sound that all the <12" speakers I have demo'd appear to lack.

    Referencing option "b", I thought about using a crossover point of 250Hz for the KLH woofer, and purchase speakers like the BIC Formula FH-65B to leverage as a replacement for the mid woofer/high range.

    I am open to any and all opinions and suggestions. Are both of these ideas reasonable or am I better off giving away the KLH's (let the crying commence) and start from the ground up?

    Thank you all!

    PS. I have been a customer of PE since 1993! Long live PE!!

    Linear Dynamics by KLH, model PR-950S
    Recommended for amps rated 5-300W
    Design: 15" - 4 way
    Cabinet: 4th Order, Ported
    Woofer: 15" polymer with ferrite magnet
    Midrange: 5 1/4" dynamic
    Tweeter: 3" liquid-cooled Kapton
    Supertweeter: 1" liquid cooled dome
    Crossover Frequencies: 900, 2800, 3400Hz
    Impedence: 6 ohms average

  • #2
    Re: KLH PR-950S - Replace drivers and crossover help

    I would consider the thought of turning the KLH into active bass bins via the addition of a new woofer and plate amp, and setting a nice 2-way monitor on top. The cutout for the KLH 15" woofer is probably similar to most other stamped frame 15" drivers, and there are a multitude to choose from - or, cut an entirely new baffle and use any of a myriad larger 3-way DIY systems.

    This is the best part of the hobby, IMHO - figuring out what to do with existing cabinets/designs. Plenty of options!
    Don't listen to me - I have not sold any $150,000 speakers.


    • #3
      Re: KLH PR-950S - Replace drivers and crossover help

      I think your first problem is the AVR. Although I've never heard it, it may not be up to snuff. Was there a time when you liked the KLH's? What were you using to drive them than?

      I have listened to the Maggie's when my Martin Logan Arieus's panels died. They are nice, but it was cheaper for me to replace the panels on my Logans so that's what I did. Electrostatic, or planer, or ribbons are a very different animal than what you'll find here. With that said,,,, I'm having much more fun with the dynamic speakers that I've built with a whole lot of input from the folks here!

      I guess what I'm trying to say is,,,, if you really like the Maggie's, save your money and buy them. If you want to play and need a hobby,,,, stick around and learn from these guys. Just be prepared to put in some serious reading and learning time.

      Johnny will be able to re-purpose those cabs into something special! Me,,,, or you,,,, not so much. If you really need to build something NOW, go with a proven design! If you really want to re-purpose those cabs, than stick around, read, and ask questions, just be ready for the long haul.

      Good luck, but most of all remember,,,, this is suppose to be fun! Those Maggie's with support from a 15in woofer,,,,, now that sounds like fun! later, Mark


      • #4
        Re: KLH PR-950S - Replace drivers and crossover help

        Thanks johnnyrichards for taking the time to reply! I appreciate the suggestion.

        The depth of the cabinets is not much. I tested a DA 15" many years ago and the magnet would just touch the back (introducing vibration). Actually, the 15" in the unit isn't terrible, it's the top-end drivers that deserve the firing squad. I do like the idea of (in essence) bi-amping the speakers sending the low-mids (under 400?) to the 15" and the rest to a nice 2-way monitor. The only issue is I am not sure how to use a crossover to do this. Perhaps an inline filter on the 15" and wide-open to the 2-way could work since the 2-way would include a crossover. Thoughts?

        Thank you again, I am happy to be back to the hobby after many years away overseas. Just need to learn all about crossover design and theory.


        • #5
          Re: KLH PR-950S - Replace drivers and crossover help

          Hi Mark (Psycoacoustics)! Thanks for replying. The AVR is new, and I have demoed quite a few. This is what I would question as well in your shoes so good thinking! In this case, Pioneer Elites are a good mid-level unit with solid construction and great reviews (for the 1500-2000 dollar range). The accuracy and performance is definitely there, but I am not as found of the brightness (totally a West Coast amp) but it can be tempered down a bit through processing. When switching to the bypass mode aka "Pure Direct" there is no noise and little to no processing. Personally I think by upgrading all my components but the speakers has shown the weak link.

          I truly enjoy speaker building as well, but I am bandwidth limited to start with a completely fresh design atm. For now I'd like to use what I have and hopefully build upon it until time allows more fun :-)

          Great idea to upgrade the KLH and then re-provision them to provide lower octave reinforcement for Maggie's. I see they even offer a panel to provide additional bass as well (Magneplanar Bass Panel (DWM)). I'm mostly not a fan of using a standalone powered sub for listening to music (depends of course on the genera of music chosen). For movies it's great to use, but this is why I didn't want to toss the KLH. 15"'s work so well for the low end without sounding muddy. Hopefully I can come up with a solution to use them or find another design leveraging 15" woofers (like a 3-way).

          Thanks for your time!



          • #6
            I have a pair of these speakers as well. Trying to determine what to do, just like Josh above.

            I'm using them in a bedroom (12x14) with a Realistic STA-47 ~12wpc amp. These sound great when watching movies (Star Wars), but if the bass gets to high, the cheap cabinets start rattling. I guess I should search for threads on re-enforcing cabinets.


            • #7
              3/4" diameter dowels connecting the opposing panels is all you need. The easiest way to install them is to cut them 1/8"-3/16" shorter than the required length, using wooden window/door mounting wedges to secure them, with woodworking glue on all of the mating surfaces. Use enough of them so there's no unbraced span of more than six inches and that cab won't vibrate.