dougdrake Posted November 25, 2002 Share Posted November 25, 2002 Since the search function of the forum is, shall we say, having a bit of a challenge, does anyone have the link or the thread regarding the modification of a Forte a la HornEd for center channel use? As I recall, some soul on this board actually did it, and I'm about to embark on the project. Lil help, please!! DD Quote Link to comment Share on other sites More sharing options...
jerohm Posted November 25, 2002 Share Posted November 25, 2002 Here are the pictures of my quartet after modification. http://pages.cthome.net/jerohm/quartet0.jpg http://pages.cthome.net/jerohm/quartet1.jpg The Beta-10 has since been replaced with another K-10-K (the correct original). The biggest problem you will encounter is that the soundboard is impossible to remove because it is fitted into a channel on all four sides of the cabinet during assembly (Forte II is defintely built the same way - I would ASSUME the Forte I is too). I cut it out with a router leaving about 3/4" lip of the soundboard. I chose to have a local cabinet maker cut, spline and frame the original soundboard with rock maple. You could always make your own, but I don't have the necessary tools. It sits right above the original position and attaches to the 3/4" lip with caulk and screws. The woofer has to sit right or left of the center, but bass is pretty much non-directional. You would not believe how good it sounds - but watch the non-shielded drivers. It is worth the effort to be able to run all speakers LARGE j Quote Link to comment Share on other sites More sharing options...
dougdrake Posted November 26, 2002 Author Share Posted November 26, 2002 Thanks for responding, jerohm. I recall the motorboard being an issue since it is so firmly installed. So, in essence, your design fits a new motorboard "on top" of the lip you left when you cut out the old one. Would you say, then, that the interior volume of the cabinet has increased since the new motorboard is 3/4" further "out" than the old one (or whatever the thickness of the old motorboard was)? I wonder if that is significant. I see also that you reversed the relative position of the mid and tweeter, with the mid now on top. Why is that? I had pictured keeping the mid below the tweeter, so it would be closer to the level of the mids on the mains. Doug Quote Link to comment Share on other sites More sharing options...
jerohm Posted November 26, 2002 Share Posted November 26, 2002 There is absolutely no question that the volume of the cabinet is increased by approx: = ( W - ( 3/4" * 2 )) * ( L - ( 3/4" * 2 )) * 3/4". ... nothing, I ASSUME, additional stuffing couldn't compensate for ... however I did NOTHING but reinstall the original 2 foam rubber pieces. As for the tweeter orientation, it is merely a matter of how I placed the speaker on mount. The top front of the speaker is 5" from the ceiling and the rear is about 3 3/4". It sits about a foot away from the wall. I just thought that the highs might get a little washed out being that close to the ceiling. It takes two to get it up there, so I don't go messing with it much. I had a defective K-10-K and was using an Eminence Beta 10 until recently. It sounded fine when set to small, but something just wasn't right when set to LARGE. I reinstalled a good K-10-K, set it to LARGE, and boy did that make a difference... most detectable when a TV station is broadcasting a mono signal. Was it worth it? I can only offer an audition of the results and you can decide for yourself. I am glad I did it, but had NO IDEA how much work was involved until I got well into the project. NO ONE TOLD ME HOW THE ORIGINAL SOUNDBOARD WAS ATTACHED AND IT WAS NO FUN FINDING OUT. After putting the project on hold for a couple of months, I came up with this much simpler design and moved forward. I am actually using the original plywood soundboard so I did not have to worry about cutting the openings. The original soundboard seemed to made from high quality (NO VOIDS) 3/8" and 1/2" plywoods glued together. The cabinet maker completely splined(maple Biscuits) all edges into a maple frame. The NEW soundboard is 'rock' solid (@ $125.00/Quartet, materials and labor ... if you can find someone you trust that will take on such a small job ... He still hasn't completed the second one, but I haven't been pushing the issue either ). The new soundboard has a tight friction edge for the grill (not using the magnets anymore) and sits on (in actually) the front of the speaker like a cap. If I remember right, Ed was using MDF for his soundboard. In that case, I think your efforts would be directed to getting the openings correct... not necessarily an easy task because each opening requires 2 separate dimensions to worry about; the front flush opening and the opening that the speaker actually mounts to. Only HE can give you tips there! Then you have the shielding issues. My project is mounted above a 40" Mitsubishi Tube and it doesn't bother it. Your situation may be different however. I guess you will just need to go out a buy one of those great big plasma sets! Good Luck and ask if you think I can help. j SECOND thoughts ... modifying a Forte I would pose additional challenges due to how the woofer 'cuts in to' the bottom of the mid-horn... Quote Link to comment Share on other sites More sharing options...
dougdrake Posted November 26, 2002 Author Share Posted November 26, 2002 jerohm - Thanks for the detailed reply. That info will be useful as I plan out the details. I wonder if the motorboard could be altered by sawing it out quite close to the 4 sides, building a new one identical in size to the removed portion, and then replacing it in the space vacated by the old motorboard, using 2x2's (for example) attached to the inside of the 4 sides to make a secure surface to reattach the motorboard to. Secure the 2x2's to the sides with strong glue and screws (careful not to make them so long they come out the other side)? Then glue/screw the motorboard to the 2x2s, and seal the "crack" between the old motorboard that was cut and the new one? If that works, it would allow the speaker to retain its original exterior shape and grill placement. Of course, the 2x2's would reduce the interior volume, but is it enough to be significant? Also, I was told that adding stuffing material inside the speaker actually increases the apparent volume, rather than decreasing it. Is that true? HDBRBuilder (and anyone else skilled at making speaker cabinets), I'd appreciate your thoughts on this design idea... Doug Quote Link to comment Share on other sites More sharing options...
jtkinney Posted November 26, 2002 Share Posted November 26, 2002 Doug, If you did it like Jerohm, you could make the motorboard extra thick to make up for the volume gain. That would change the grill though. The other way, like you described, cut the original motorboard out with a flush cutting router, then add blocking to attach the new one. You could cut the 2x2 blocking into a triangle shape to lessen the volume change, or add more stuffing. Adding stuffing does make the speakers think the box is bigger. The new motorboard could be MDF or plywood. Quote Link to comment Share on other sites More sharing options...
HornEd Posted December 25, 2002 Share Posted December 25, 2002 Doug, while spending early Christmas morning looking up old posts that I had missed and came upon this one. My congrats to your "center" forward thinking. As you know, Mr. Paul designed most of the Heritage line in attempts to build a better quality center for Klipschorns! The Belle was the extreme example of the length PWK went to please his wife by having a "good looking" cabinet smaller than a Klipschorn that didn't need a corner and still matched closely enough the K-Horns for timbre by PWK's ear. Of course, the LaScala's were also built as a fully loaded horn center but failed Belle's (the wife, that is) beauty bias. It would seem that your idea to cut a "window" in the existing motorboard and then glue 1/4" (minimum) hardwood strips as flanges to which an MDF panel with new speaker cut-outs is glued (the Klipsch factory uses "Liquid Nails"). MDF makes a great motorboard and I much prefer it to less-than-the-best plywood... where voids are a sound hazard. On mounting the question of mounting the exponential horn and tweeter, bear in mind that the tweeter is most dependent upon line-of-sight (hmm, perhaps that should be line-of-ear) for best results. Thus, depending on what level your ears are likely to be you should be able to decide which should be on top. I have tried center speakers mounted below and above screen. Above screen works best for most room configurations IMHO. However, people with projectors and specialized screens can positon their center channel Forte in the ideal behind mid-screen" location. Having had the experience of Klipschorn-Belle-Klipschorn front array for DVD's... I remain convinced that there is no center speaker like the one that closely matches one's mains... and, of course, when it comes to DVD gratification... an adequate subwoofer system that can meet the Dolby minimum standard for professional theaters (121.5 dB) makes it possible to hear virtually all the sound recorded on a Dolby DVD. Frankly, it is amazing how much sound most peopole miss with their high priced mini-centers and maxi-subs that just don't measure up. Give your family the joy of full movie sound BEFORE next Christmas! -HornED Quote Link to comment Share on other sites More sharing options...
dougdrake Posted December 25, 2002 Author Share Posted December 25, 2002 ---------------- On 12/25/2002 11:15:49 AM HornEd wrote: Give your family the joy of full movie sound BEFORE next Christmas! -HornED ---------------- Hi Ed - Thanks for weighing in on this. I had taken your silence simply as an indicator of your busy schedule coupled with your recent health challenges. Glad you have a few moments of quiet on this wonderful day, as do I whilst my wife makes a quick milk-run to the convenience mart. I hope I can have this project done before NEXT Christmas. However, I must complete the rebuild-the-entire-kitchen/greatroom-countertops-with-mucho-reinforcing-so-I-can-tile-them-with-granite-and-not-have-the-sides-cave-in-under-the-weight project first. I was considering using metal strips, about 1-1 1/2 inches wide, in place of wood for the flanges. That would minimize decreases in interior volume, and provide (I believe) a much stronger surface to attach the "window" to, using a bead of caulk on the flanges along with bolts through the edges of the "window" and the flange. Might give it that nice Frankenstein look, don't you think? Doug Quote Link to comment Share on other sites More sharing options...
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