johnnyp

I suspect the cause of your sibilance problem ("spitting s" sounds) lies within your music source. I've listened to a bunch of Cd players and phono cartridges that had this problem. I suggest you borrow a "high-end" CD player from a friend or dealer (one that does not exhibit this problem on their system). ------------------ John Packard

Ed, I thought you were using a Monarchy SM-70? How did it compare to what you are using now? ------------------ John Packard

Jason, I think you should try and borrow and good quality CD player from a friend and fellow Texan and try it on your system. I have heard some complain similarly when they use their DVD as a music source. ------------------ John Packard

Consider BGW. I have listened to BGW, Crown, Adcom, Carver, and Phase Linear on klipsch at home and by far BGW was the most pleasing. But get only the BGW 250/750 Series amps; I had a BGW Proline in my basement that I didn't like at all. The good news is BGW is cheap on eBay. In fact, there is someone in FL who sells BGW regularly on eBay. If you buy and don't like it, you should be able to get what you paid for it. Or, save it to use as a subwoofer amp. ------------------ John Packard

I believe I read something about removing the bug screens on the K-55* drivers but I can't remember what the verdict was. When I searched the archives I couldn't find any info. I read recently on another forum where a group of audio enthusiasts thought removing the bug screens was a good idea -- for sonic improvement. Has anyone done this on their K-55s? What was your impression? How hard was bug screen to remove? ------------------ John Packard

Allan S: Go back and read the posts under the topic "My Terrible Secret" (06-20-2001) in this forum. Then read John Warren's comments again. I interpreted his comments as humorous at least and mildly sarcastic at the most! I, for one, would enjoy reading a discussion here from those who believe (and don't believe) the need for "breaking in" of esoteric, mega-buck capacitors. Is there any empirical before-and-after evidence to support this arcane phenomenon? ------------------ John Packard

My good friend had a similar complaint. He unscrewed his K-55V and took it into his Klipsch dealer. The dealer installed it on one of a pair of Khorns in the audition room and played some music. The dealer said he could hear nothing wrong with the driver but my friend insisted he could. A technician at the K dealership ran a frequency sweep test on the driver. Sure enough, there was excessive distortion only at frequencies near 700 Hz. The K dealer apologized and gave my friend a new K-55 V driver -- free. If your driver has push-on terminals, note the polarization ("+" and "-") of your driver before removing the wires. Terminals on all K-55s are labeled with a small raised "1" or "2". Disassemble your problem driver by removing the 6 screws. Carefully pull or pry the driver apart. Locate the blind hole (about the dia. of a pencil) in the center of the driver half that contains the magnet structure. In the hole, you will find a wad of felt or lint. Sometimes, some of the lint fibers work their way up the hole and begin rubbing on the diaphragm when the driver is operating. You will hear the raspy sound you described when this happens. Remove only the loose lint fibers or gently push them slightly deeper into the hole. carefully reassemble your driver, tightening screws opposite of each other like you are attaching a wheel to your car. Install your driver and attach the wires to their original polarity. Then test. Your problem may now be corrected. Otherwise, you must order a new diaphragm from Klipsch or send your driver to them for repair. ------------------ John Packard

Al or djk: Instead of the P-trap, what about a simple inductor in series with the K55V on the A-A network to tame all high frequencies above ~6K? Has anybody tried this? To calculate the inductor value, what value of R should I assume for the K55V -- 12 ohms? Is the R for the inductor calculation affected by the autoformer R? ------------------ John Packard

Mr. Blorry I agree! I am a fan of Flim & the BB's! I have "Tricycle", "The Further Adventures of Flim & the BB's, and my favorite, "Big Notes". These CD's are recorded very well indeed. On some tracks you can hear the valves open on the saxaphone! To learn if you will like the Flim, go to your favorite cd e-store and sample track #2: "Heart Throb" from the Album "Big Notes" or go here: http://www.cdnow.com/cgi-bin/mserver/SID=1345668589/pagename=/RP/CDN/FIND/album.html/ArtistID=FLIM+&+BB%27S/ITEMID=335954 On track #11, there is some low bass near the 4 minute mark. I have never heard this track played correctly on any system (regardless of price) at any appreciable volume level. Another well recorded CD in my collection: "Between Father Sky and Mother Earth". This is native-american music. Worth the cost of this CD for tracks #4 & #14. My favorite track is #14: "500 Drums". If your spouse still loves you after 8 minutes of tom-toms, you should consider yourself lucky!

Ditto, Gil. But SETI has the coolest screen saver I've ever seen! ------------------ John Packard

Thanks, djk, for the link (above) to a most unusual PWK crossover design. Note: there is no autoformer in the mid circuit but there is one in the tweeter circuit where it is wired "inversely" to increase tweeter output. (this crossover is used for a new, super-efficient speaker designed to produce 108dB @ 1w/m). After reading the text accompanying this design, I believe the LC values shown in the squawker (mid) circuit to roll-off the high frequencies may not be the ideal values to use for AA crossover tweakers. According to his text, the "L22 , C22 produce a rise at approximately 5,500 Hz." (PWK, page 9/10, lines 27 & 28). He has selected these LC values to increase output at 5,500 Hz in the mid circuit before they begin to roll off the highs. Likewise, the monster 128uF cap across the woofer terminals increases output at 350 Hz (page 9/10, line 25). Crossover tweekers may want to experiment with a smaller value for the C22 capacitor (maybe 1uF - 2uF) to minimize the resonance at 5,500 Hz. Looking at the ALK design, I noticed he has chosen to use the L22/C22 combo before the autoformer in the squawker circuit. Don't know if this would make a difference.

Al, If I understand you correctly, the .3 mH squawker inductor shunts some of the high frequencies to the squawker but also "balances" the tweeter circuit. Likewise, the 2.4mH woofer inductor shunts highs to the woofer and is essential to "balance" the mid/tweeter circuit. I think there is a dim light beginning to glow between my ears! I have read some posts here that suggest running the woofer "full-range" without the 2.4 mH inductor (letting the natural rolloff of the woofer/cabinet shunt the highs). But you would not advocate this for your design or the AA, would you?

Al, Thanks for the graphs. I am still trying to interpret the results but I think you are misleading (and short changing your design) by not using a consistant scale. For example, in the A-A graphs you indicate "Delay 0.100 mSec/div and "Z 5.0 ohms/div." For your ALK graph you use "Delay 0.050 mSec/div" and "Z 0.2 ohms/div". The comparison is A bit misleading to a casual viewer. Looking at your schematic and the AA schematic, both designs for the tweeter circuit include the big capacitor used in the squawker circuit (in your design, it's the 39uF + 1uF caps). The formula I use for summing caps connected in series tells me the additional cap from the squawker changes the total capacitance very little (1/40 + 1/2.2 = 1/Total = 2.08 vs 2.2 without the 40uF in series) So why do you use it?

edster00: Curious about your Monarchy. I know it was on Soundstage Reviewer's Choice List one year. Do you find 25 wpc sufficient? What other amps have you tried? What do you use for a pre-amp?

... in defense of SS Class A design, not all are bad. Please consider the following: http://www.soundstage.com/revequip/monarchy_sm70.htm Read the whole review or use your browers' "FIND" command to locate "SET" in the above article. Then read the comments offered when this amp was compared to a SET amp in a system featuring Klipsch Cornwalls. No, I haven't auditioned it but would love to.

Thanks, John W. I read PWK's paper on the Khorn long ago and I think I remember there was a calculation and a statement regarding the critical-ness of the volume of air between the woofer cone and the slot. I hope to try an extra gasket in my enclosure soon. I have already tried the 6" x 13" slot but didn't much care for the results. Have you ever tried the larger slot and what were your impressions? ------------------ John Packard

I think the Klipschorn bass units are good up to about 700 cps. What do you plan to use for the top end?

In view MVC-026X.JPG, what is the purpose of the triangular-shaped cut-outs near the edges of the board that contain the slot? I've never seen that before. Looking at the photo again, perhaps it adds stiffening to the side walls without reducing the back-chamber volume? I used 10 coats of marine-grade clear polyurethane in the slot region on my pair. It left a finish as smooth as glass on the phase plug board. I was hoping it would improve bass impact but all it did was improve the upper bass frequency response. ------------------ John Packard

Beautiful work, John. Looks like Birch plywood maybe? What do you plan to use for woofers?

JLH: I cannot comment on how the Dayton woofer sounds in a genuine Klipsch enclosure. My bass units are not Klipsch made but are modeled after the Klipsch design. I can say that I much prefer the Dayton woofers over the McCauley woofesr which I used previously. I'm NOT saying the McCauley is an inferior speaker -- the ones I tried just weren't designed for horn loading. The Dayton gives me at least an extra octave of bottom end compared to the McCauley. The T/S parameters are similar for the Dayton and the Klipsch K-33E. If you have genuine Klipsch enclosures I'd stick with the factory drivers. Gil: Yes, I wish someone would clarify the woofer spacer issue. The optimum spacer distance is probably woofer dependent. But which T/S parameter would affect it? Perhaps the plywood spacer (with the circular cut-out) was used on earlier K-horns to simplify manufactuiring and woofer installation?

Mark, You have a bunch of nice equipment listed and I'm sure it all sounds superb. When I see the photo of your transformed speakers, I am immediately reminded of the movie "The Fly".

Thanks for the replies. I am using a pair of Dayton 15" drivers which have an X-max of 7.9mm. The drivers' complete specs can be found at: http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Product_ID=7751&CATID=49 I installed one driver in the bass unit with no spacer and only (2) screws. Then I ran some 40hz test tones. When I turned up the volume, I could hear the speaker diaphragm smacking the wood! That's when I tried the 1.5" spacer but didn't care for the sound -- too subdued. Now that I have secured both speakers with (8) mounting screws (each) and no spacers I can't hear the diaphragm collision anymore. I believe the drivers are sealed to the board now. At moderate volume, does the slot create a "cushion of air" between the slot and the speaker diaphragm, limiting diaphragm movement and collision with the board?

I am thinking of tinkering with my home-built cornerhorns again. In the Paul Klipsch designed Heritage horn bass units (Klipschorn, Belle, LaScala), what is the optimum distance the woofer should be mounted above the slot? Correct me if I am wrong but Klipsch, at one time, mounted the woofer directly to the board containing the slot. I think I recently read a thread on this BB where Klipsch is spacing the woofer from the slot using a double-thick gasket. At other times they mounted the woofer to a 1/2" or 3/4" plywood spacer with a ~14" dia. cut-out. Volvotreter has elected to use a spacer above the slot in his LaScala project. http://www.klipsch.com/ubb/uploads/volvotreter/MiniLaScala.jpg (Volvotreter: I hope you don't mind me showing your work -- I am envious of your woodworking skills!) I have tried mounting my woofer to a 1.5" thick cut-out I have available from another speaker project but I wasn't impressed with the results. What would be the characteristics of the sound if the woofer is mounted too close to the slot or too far away? ------------------ John Packard

Chris, I use the radio shack solder too. The solder container says it has 4% silver. I believe you may have pulled the diaphragm leads too tight before you soldered them. This can restrict free movement of the diaphragm. It happened to me years ago when I soldered a new diaphragm on a mid-range driver. You may want to attempt to resolder leaving a little slack in the diaphragm leads between the soldering posts and the voice coil. Let us know what happens.