3dzapper Posted January 31, 2005 Share Posted January 31, 2005 Here are a series of pics showing the installation of an 8 Ohm L-pad for the tweeter and a 16 Ohm pad for the squaker: This is the new, braced, backpanel that I cut so as to preserve the originals. The L-pads are installed http://forums.klipsch.com/idealbb/files/hconstr.jpg This is the insides showing some of the other mods I have done previously. http://forums.klipsch.com/idealbb/files/hin.jpg Here is the back wired in to the drivers and x-over. Notice the K-55v in this shot and K-53 in the other? More later. http://forums.klipsch.com/idealbb/files/hhookup.jpg This is what the new back looks like with the new controls and binding posts. http://forums.klipsch.com/idealbb/files/hback.jpg Rick Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted January 31, 2005 Share Posted January 31, 2005 Good job Rick. How do they sound? Once you find the "perfect settings" you can use a meter to measure the resistance values and then replace the L-pads with audio grade resistors (on the crossovers). You may even want to post the numbers so others here can try it. Andy Quote Link to comment Share on other sites More sharing options...
3dzapper Posted January 31, 2005 Author Share Posted January 31, 2005 ---------------- On 1/31/2005 2:12:24 PM Klipschguy wrote: Good job Rick. How do they sound? Once you find the "perfect settings" you can use a meter to measure the resistance values and then replace the L-pads with audio grade resistors (on the crossovers). You may even want to post the numbers so others here can try it. Andy ---------------- Thanks Andy. Would you believe they sound like the've got woofers? Not that they go any lower, but I can actually hear the bass over the midrange. I've got to go out later so tomorrow I'll run some test signals through them to see if my ears and the meter agree on frequency response. I've got the squakers down 5db and the tweeters 3db at present. I will take some Ohm readings when I get them "perfect" and post them here. Of "coarse" my perfect might not be yours in your room if you know what I mean. That is where the variable L-pads come in handy. Rick Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted January 31, 2005 Share Posted January 31, 2005 Sounds good Rick. I am running a pair of L-pads in a recent speaker design and I plan on leaving them (but I did whip out the old meter just for grins). Everybody's ears are a little different, but I'll bet your numbers are gonna be a good match for a number of people. Especially if Khorns are your ears reference mark. I think PWK wanted that 96dB/1m/1w rating out of his Heresy design instead of 92.5 (or whatever). Andy BTW, do you like the damping material in your cabinets? I tried it in my Heresys (which now belong to a friend) and felt like I had a noticable loss in dynamics without any appreciable extension. Quote Link to comment Share on other sites More sharing options...
Daddy Dee Posted January 31, 2005 Share Posted January 31, 2005 nice work. good food for thought. Quote Link to comment Share on other sites More sharing options...
Born2RockU Posted January 31, 2005 Share Posted January 31, 2005 ...Nice job. I would love to do this to my Heresy II's, BUT the backs do not come off !! I have L-Pads (thanx to Erik Mandaville's assistance) on all of my front stage (K-Horn, LaScala, K-Horn) and would love to install L-Pads on my 4 Heresy II's, ....which I use for my rear surround stage ! Quote Link to comment Share on other sites More sharing options...
3dzapper Posted January 31, 2005 Author Share Posted January 31, 2005 In order to do the HIIs you'd have to cut holes in the back and wire them through the woofer hole. Here are my Khorn L-pads Craig: http://forums.klipsch.com/idealbb/files/Khornlpad.jpg Rick Quote Link to comment Share on other sites More sharing options...
Born2RockU Posted January 31, 2005 Share Posted January 31, 2005 In order to do the H IIs you'd have to cut holes in the back ..... YIKES !!!!!!!!!!! Quote Link to comment Share on other sites More sharing options...
Deang Posted January 31, 2005 Share Posted January 31, 2005 Rick, I'm a little embarassed to ask this -- but how does the wiring work in relationship to the network? I also need a little help trying to understand what an L-pad accomplishes that can't be accomplished with an equalizer. Quote Link to comment Share on other sites More sharing options...
Deang Posted January 31, 2005 Share Posted January 31, 2005 Yeah, no one likes cutting into their new speakers. You should have seen me drilling into my new Klipschorns -- I was a basket case. Quote Link to comment Share on other sites More sharing options...
Professor.Ham.Slap Posted January 31, 2005 Share Posted January 31, 2005 ---------------- On 1/31/2005 5:43:17 PM DeanG wrote: Rick, I'm a little embarassed to ask this -- but how does the wiring work in relationship to the network? ---------------- If I'm reading the lines right, the main line in goes into the network, then each dial is hooked into their respective tap (high and mid). The tweeter and the horn is then directly connected to the L-pad. Quote Link to comment Share on other sites More sharing options...
3dzapper Posted January 31, 2005 Author Share Posted January 31, 2005 Amp Speaker The L-pad is in series with the negative lead and parrallel with the driver. As the resistance is increased in the series loop the parrallel resistance drops maintaining the impedance load on the network and amplifier. The reasons I feel an L-pad is prefferential are: The equalizer is working in a low level envrionment before the amplifier, any noise or distortion produced by the Eq will then be amplified. The L-pads are wire wound and less likely to inject noise than carbon sliders especially at the higher level envrionment where they are applied. Portability, wherever the speaker travels, the equalization goes along and can be adjusted to tune it to it's new location. Rick Quote Link to comment Share on other sites More sharing options...
Klipschguy Posted January 31, 2005 Share Posted January 31, 2005 You don't have to drill the rear panel. Just use a resistor L-pad on the crossover network (that's where the meter comes in handy). When wiring an L-pad, I always like to wire them AFTER any capacitors (or autoformers) so that the L-pad is not receiving a full power amplifier signal, i.e. 100W. It is just getting the signal after the capacitor, which in the case of the tweeter network is only a small fraction of the total output from the amplifier. One time I wired some L-pads the other way in pair of speakers my brother and I built and we absolutely SMOKED those babies with a high power amplifier. The acrid smell of burnt lacquer (magnet wire insulation) hung in the air for hours. I wired the new ones after the caps. We tried to fry them and couldn't. That project was done over ten years ago and his speakers are still singing sweetly. The L-pads are still quiet as a mouse too. Best regards, Andy Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted January 31, 2005 Share Posted January 31, 2005 Hi, Rick: I'm glad the L-pads are working out for you. Craig: I'm pretty sure we could work out L-pads for the Heresies. Is the back panel not removable at all? If not, you'd need to drill a hole for the L-pad shaft, and would gain access to the inside of the enclosure by removing the woofer. Once that's done, the rest is easy. If you're planning to always keep these for yourself, you might consider that as an option. Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted January 31, 2005 Share Posted January 31, 2005 Andy: You're right, of course. it isn't necessary to drill the back panel -- which would just allow a little more flexibility. The networks I built for my Klipschorns and La Scala all have L-pads, which are mounted directly to the crossover board. The L-pads were taken apart, a small hole was drilled in the metal housing, and the the actual resistive network was reinstalled and clipped into place. This works fine because the crossovers in the big horns are accessable from the rear. With a Heresy, it seems the only way to make accurate adjustments of the output, at least as far as I can tell, would be to drill a hole in the back panel for the L-pad shaft -- which is what Rick has done. Craig: You could always remove the original back panel of the Heresy/ies, and make another of the same dimensions that you wouldn't mind drilling for L-pad use. The original could always be put back on again if you ever decided to sell them. Quote Link to comment Share on other sites More sharing options...
Born2RockU Posted January 31, 2005 Share Posted January 31, 2005 ERIK : ...Thats a great idea ! Would it be NO problem? BUT, is the L-Pad's "control-knob" shaft long enough to extend thru the back panel ??? - A L S O - ~ Doesn't the Heresy II cabinet need to be SEALED !!! ~ Wouldn't this create air leakage...or it wouldn't matter ??? Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted January 31, 2005 Share Posted January 31, 2005 It would still work as a sealed enclosure. I have done two things to work with this issue: 1)use a soft rubber 'O' ring between the threaded shaft and the panel which compresses when the nut is tightened. 2)neatly apply a thin bead of silicone glue around the junction of the L-pad shaft and panel. The hole that's drilled should naturally be very close to the actual size of the shaft. Even those things probably aren't necessary. Since the Heresies are used in the surrounds, they probably aren't seeing much bass response anyway. My Lexicon (once it arrives)will be able to roll off to the center, sides, and rear surrounds, but I don't know if your processor has that feature (?) remember we were talking about it this weekend? The L-pad should work fine in the Heresy. Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 31, 2005 Share Posted January 31, 2005 " My Lexicon ......" Details please! Congratulations! Have fun, (I know you will....) Shawn Quote Link to comment Share on other sites More sharing options...
Erik Mandaville Posted January 31, 2005 Share Posted January 31, 2005 BUT, is the L-Pad's "control-knob" shaft long enough to extend thru the back panel ??? What I do with this is use a two-inch hole-cutter in my drill. A sqaure piece of either 1/4" ply or masonite is then attached on the inside to cover the 2" hole. So, you now have a two-inch cut-out in the back panel, with a sort of sub-panel, with one hole left to drill for the L-pad shaft. Hi, Shawn: Indeed it is true! Details were finalized this evening for a version 4 model DC-1. I'm really excited about it! Quote Link to comment Share on other sites More sharing options...
sfogg Posted January 31, 2005 Share Posted January 31, 2005 Erik, "Indeed it is true! Details were finalized this evening for a version 4 model DC-1. I'm really excited about it!" Fantastic! That is the same software level (the latest version) as the one you borrowed from me. Is it a DD model or a DD/DTS model? Not that that really matters for music listening... just curious. Have fun! Shawn Quote Link to comment Share on other sites More sharing options...
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