Midwest Audio Fest

It’s that time audio enthusiasts! Registration for the 2019 Speaker Design Competition is now open! Visit for details and to list your speaker project. We are excited to see all returning participants, and look forward to meeting some new designers this year, as well! Be sure your plans include a visit to the Parts Express Tent Sale for the lowest prices of the year, and the Audio Swap Meet where you can buy and trade with other audio fans. We hope to see you this summer! Vivian and Jill
See more
See less

KLH Model 6 Ideas

  • Filter
  • Time
  • Show
Clear All
new posts

  • KLH Model 6 Ideas

    My Daughter found some old cabinets from some KLH Model 6 speakers. The drivers are all gone, but the boxes and baffles are in good shape and she likes them aesthetically. I am looking for ideas on what to put into them. The results should be good, but don't have to be great. These will most likely sit on the floor of her apartment and usually not face the listener.

    I thought about putting some average GRS woofer and a Faital 3" with a simple coil and cap. I even thought about adding an LPAD for the 3". The sensitivities are tricky. I'm looking for ideas under $200.00.

    The original woofer size was closer to an 11" and the "tweeter" was closer to a 4.5" I was thinking about cutting some kind of fill plate and mounting a 10", but an 8" would be easier. It might be easier to find a good 7" two way design and go with it.

    Here are the dimensions.

    Internal Dimensions

    Depth - 9.25 (1/4)
    Width - 11.125 (1/8)
    Height - 22.0625 (1/16)
    Internal Volume - 1.31

    Woofer Cut
    Inner - 9.25
    Outer - 10 7/8

    Tweeter Cut - 4.25

    Panel Thickness .75

    I don't want to modify the cover because of the fabric so the tall order is a 2driver system.

    I wanted to fish for ideas before I ordered.

  • #2
    The pictures are from online because the cabinets are at her house, but the measurements are the ones I took.


    • #3
      I would be tempted to do a modified version of this:

      Uses the GRS 10SW-4 as a woofer and Vifa tc9fd as mid. I would build as sealed (rather than aperiodic ), forget the tweeter, and modify the crossover to eliminate the low pass on the mid. The Vifa will work fine as a full range without a tweeter.

      The woofer looks like it may fit the baffle, and you could use cardboard to make the Vita fit.


      • #4
        I really like that idea, Michael!

        Looking around some more this evening I think I'm going to go with a DC200 and DC28 two way. I know the drivers and trust them and I have heard some other designs from some of the guys who worked on some of the models I'm finding.

        I realize that the box size being static is a limitation, and that I shouldn't expect great midrange or great distortion profiles from this combo, but those were the compromises from the beginning.

        I'm looking at WinISD and seeing a 1.3 cu Ft ported and tuned to 28.72 is the best I can get with the DC200.

        I found these models for crossovers.

        I know the box size and baffle layout will affect the results, but I think I'll look at these more closely tomorrow and see what gets me closest.


        • #5
          The DC250 looks like it would work pretty well also. I would suggest keeping the box sealed for tighter sounding bass. Deep resonant bass is not ideal for an apartment setting.


          • #6
            The Vifa tc9 is a full range and you can cross as a mid, anywhere above 500 hz. Really my suggestion is almost a FAST, full range and subwoofer assist. Will require much less work than other options. Using the DC28 means you have to cross much higher. Hard to cross and 8 inch or 10 inch to a tweeter. Also, on design you propose, if you look at first thread, they take you to another thread which at end has different crossover using a 2 mh coil and not a .5 mh coil. The design came from an MTM version of that speaker combo, and I think they hay have halved the coil and not doubled it. A 2mh coil makes much more sense to me (but I am no crossover expert). Also, it is an old design, and the DC28 may be different. If you are going to rebuild baffles anyway, I would use a 6 1/2 or 7 inch woofer, much better cross to a tweeter. Maybe an Amiga ( or even a Classix 2.5) from Paul Carmody's website.

            Here is a design using the DC250 and DC28, and the tread discusses some issues.

            Best of luck no matter how you go.


            • #7
              One final note. I would be very tempted by the vintage 2 way using dc250 and dc28. The crossover looks right and sims are shown. In an apartment with room reflections, not sure off axis matters much. Also holes fit, so you will not have to do new baffle. Plus, I have always heard the dc250 has smoother mids than the dc200.


              • #8
                If you're going to run some sims (to compare those XOs), let me caution you against using PE's published .frd files for the 275-070 "Silky". Their data (as well as the published graph) show an ave. SPL around 93dB - EVEN THOUGH it's been stated (OFTEN) as about 89dB. Something is wrong there.

                The really complex XO (very high parts count) gives a swing of approx. +11 to +12dB to the woofer roughly in the octave from 1k to 2kHz. Yeow! (these are ultimately "textbook" XOs that did not make use of .frd/.zma files - LOOKs like "XOver Pro" to me?)
                The "textbook" (w/Zobel & L-pad) filter (Noah's 8s) yields about 84dB +/-4dB w/little to no baffle-step - which is a lot better than the complex XO.
                My 7-element XO is about 82dB +/-2dB w/about +4dBSC (using 10 yr old .frd files for the DC200).
                Results using the newer (suspect? ? ?) .frd files for the 8" can be bettered by upping the 10uF cap (the one in parallel w/the .50mH coil on the woofer) to more like 15uF. I'd "redo" this simple (but effective) XO if someone gave me new measured files for the current 275-070 & 295-310 drivers.

                Personally (for your KLH 6 boxes) I'd go w/a 10" long 3" id port (Fb in the mid 30s), exiting it out the back (behind the woofer) turning it up w/an elbow, w/the internal end up behind the tweeter. I still enjoy my "Classic" 8" 2-ways that are over 15 yrs. old now (and they HAVE been "bottomed out" quite a number of times).

                (Also, if you're gonna plug the old woofer hole, it would be best to move the new one up close to the tweeter. Just a thought.)


                • #9
                  The GRS10sw is a good woofer suggestion, maybe paired with this coax for less cutting: