Mallette Posted June 25, 2002 Author Share Posted June 25, 2002 OK, guys, I've done some measurements and some thinking. Big trouble ahead! But first... When I was a kid, I absolutely idolized Abe Lincoln. Thought he was as sinless as Christ, and brilliant as da Vinci. Then I read Frost and a few other objective biographers, and was pretty let down. Then, I got to thinking about how Abe overcame his human frailties to achieve one of the sublime moments in human history, and he now resides even higher in my esteem than before. What to do with PWK. I hung on every word he said when I visited him in the days of my youth. For 3 decades I considered anything contrary to the teachings of the Master to be bullshit not worthy of contemplation. However, being, in spite of my tendencey to hero worship, a fairly objective sort, I've spent a bit of time questioning the foundations of some of his reasoning, especially the notorious rubric number 7. Not only did he state this, it is in his 8 commandments as committed to an AES paper...not just in a marketing brochure. Heavy stuff. I am not going to go over it entirely, but some of you will have read my musings on the "why" of 7. PWK's belief in the corner horn as the ultimate, and only, trully honest loudspeaker. The unlikeliness of perfect rooms, the problems with the spouse and room decor if the speakers were on the short wall requiring seating in the middle, etc., resultling in his decision to require a center speaker. (My thinking is) He could not suggest the center channel a corrective measure to make up for the above "deficiencies," as that would somehow suggest the design was flawed. For a man like PWK, he had to square this with science, not marketing. So he drew on the Bell labs experiments and made it law. Your thoughts on this, HDBR, MH, all great experts, would interest me greatly. Now, my room has gotten a bit blown out of proportion. Actual speaker to speaker center is about 21 feet. Speaker center to apex of triangle (where my ears are) is about 16. Hardly equilateral, but not as bad as reported in the press. As I've said, imaging is much improved with the Cornwall, but since it is fed with a signal dirived from L+R after the power amp, it is slightly less pronounced than a more efficient La Scala, Belle, or Heresy might be. Jeff has a Heresy I hope he can bring over at some point to test this theory. As a music lover, suffice it to say I LOVE my system. Would I like to have better imaging? Sure. Would I like to have a Rockport? You bet. But none of that prevents the wondrous shivers and exultation that courses through my body when the music starts... Life is too short to be ruined by constant desire. More audiophiles should take a bit of time to read Lao Tzu. :-> Dave ------------------ David A. Mallett Average system component age: 30 years. Performance: Timeless Quote Link to comment Share on other sites More sharing options...
eq_shadimar Posted June 25, 2002 Share Posted June 25, 2002 quote: Originally posted by Mallett: Now, my room has gotten a bit blown out of proportion. Actual speaker to speaker center is about 21 feet. Speaker center to apex of triangle (where my ears are) is about 16. Hardly equilateral, but not as bad as reported in the press. Opps sorry about that Dave. Like I said I was only guessing It really does sound awesome and you don't get a nasty humm when you crank it so that is a plus Laters, ------------------ ...wake up to find out that you are the eyes of the world... My Home Theater Page Quote Link to comment Share on other sites More sharing options...
fini Posted June 25, 2002 Share Posted June 25, 2002 Also, glad to hear your head isn't (necessarily) a foot wide. fini Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted June 25, 2002 Share Posted June 25, 2002 Dave, I agree with what PWK proposed in the three speaker array, but I believe you are confused as to what it is all really about...the center speaker is just to provide the listener with a better coverage of MORE AREA of the room so that he/she need not sit in what audiophiles call the "sweet spot" in order to have the full effect of stereo. He NEVER said that a "hole" was "a certainty" between two K-horns..instead he said that more fill of stereo effect would occur THROUGHOUT the room with a center speaker...leaving the listener the ability to place him/herself in other places beside the "sweet spot" and still have stereo effect!! Basically, this means that the center channel EXPANDS the ideal listening area...but in order to take advantage of this, you must also be within the original ideal coverage area of both the left and right speaker. You really need to read his paper on the subject again to correct your understanding of it...it is in a letter format (which he wrote)in the recent book about him, too. He also readily admits it wasn't HIS idea, but one that he adopted from the testing done at Bell labs in the 1920's or 1930's. Don't read things into what he says about this subject...just read what HE DOES SAY, and you will understand it more clearly. He even includes geometric patterns of coverage area of a room with speakers in the corners, the doubling mirror effect of that placement, and how coverage area is increased by the center channel speaker...the pictures alone tell his story, without even reading the article. They also show the areas in which a listener MAY place him/herself OUT OF the desired coverage area...as you did by being TOO FAR FORWARD toward the front of the room when you listened to those speakers the other day...THE DISPERSION AREA COVERAGE WAS BEHIND WHERE YOU WERE SITTING...again, his diagrams will clearly show that...read it again, please. BTW...the dead center of "sweet spot" for left and right speakers 21' apart would be 18.19' back from center of front wall...with speaker coverage area extending from around 14' to 22' back from center of front wall...you were barely within that coverage area...which put the soundstage effect to your sides instead of to your front, creating that "hole"...in other words, farther back than 18.19' puts soundstage imaging to your front...and closer than 18.19' puts soundstage imaging to your sides...at EXACTLY 18.19' back, soundstage imaging is aimed directly where it should be...the perfect "sweet spot", but it is better to be back a bit than forward a bit from that centerline distance...so that soundstage and imaging flows across your front, as intended. Try it...without the center channel...you will see what I mean! Just move chair from 18.19' forward some, then back some! Then add the center channel in...and try it again! The reason PWK preferred speaker placement along the long wall of the room was to widen the coverage area...in order to provide a greater fill within the room....even if doing so would require putting the k-horns in false corners to achieve BOTH the expansion of the dispersion area, and allow for re-directing the centerline of fire to the center listening position("sweet spot")...false corners allow for re-directing this centerline of fire of k-horns more forward to the room front in this case, by allowing them to be "toed inward" some to achieve this...just as in his living room at his home. Just stand 18.19" from center of front wall...now take a step forward and listen....the imaging has spread a bit more arond your left and right side, but a "hole" begins to open up in the middle...take another step forward, and the imaging moves further out, but the hole gets larger...etc...etc...then walk backward one step at a time until you are at 18.19'...watch it change back...now take a step back...watch the soundstage narrow and the "hole" close up...each step back narrows the soundstage a bit more, but the hole is never there again. In order to eliminate that "hole" forward of 18.19', you must toe the speakers inward some...just try all of this...be sure to listen with your eyes closed to "see" the imaging and soundstage change with just your ears...you will see what I am talking about...AND what PWK was talking about. ------------------ I can now receive private messages This message has been edited by HDBRbuilder on 06-26-2002 at 12:54 AM Quote Link to comment Share on other sites More sharing options...
edster00 Posted June 26, 2002 Share Posted June 26, 2002 HDBR, I am not following your calculations for the sweet spot for some reason. Can you explain it again for a "calculation challenged" individual? What do you calculate the sweet spot for K-horns in a 13.5' wide room? Thanks! Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted June 26, 2002 Share Posted June 26, 2002 Ed, Ok, you got a wall, corner to corner that is 13.5'....that is base of equilateral triangle..all sides of this triangle are equal. You find the middle of that wall at 6.75' from each corner...draw a line out to top of equalateral triangle from center of that wall...now you have TWO right triangles. Base of one right triangle is now 6.75', hypotenuse is 13.5'...use pythagorean theorem to figure other side which is distance out from that wall(former height of that earlier equalateral triangle). The distance out is 11.69'...that is "center of mass for sweet spot". OK? ------------------ I can now receive private messages Quote Link to comment Share on other sites More sharing options...
edster00 Posted June 26, 2002 Share Posted June 26, 2002 Alrighty then...I get it! What I have been doing is drawing a line @ 45° from the corner behind each speaker (through the center of the speaker) and measuring where they cross. Here is a crude drawing of what I was thinking (not to scale)... I thought the sweet spot was where the black lines meet, yours is where the red lines meet. I am glad you set me straight! Quote Link to comment Share on other sites More sharing options...
Mallette Posted June 26, 2002 Author Share Posted June 26, 2002 Thanks HDBR, and all, for input on this thread. Since 18' puts me behind a sink in the master bath, I am going to have to live with the situation...which is still very, very, nice indeed. While I could easily place a false wall in my living room and would have PLENTY of sweet zone, that would entail having to compete with the TV again. I'd rather have less image anytime I feel the urge than a great image I can't use because "ER" is on. Even the PAW requires maintenance to keep her that way! Should we be blessed with the resources to do so, we have eventual add on plans (which will be based on the needs of K'horns!) for a separate family room. In the meantime, I remain happy and content to be lucky enough to have what I do. Got the stylus replacement for my Grado. In luck yet a third time-no hum, just really great music. Also managed MacGyver a solution to the SME meeting the back part of the dust cover. I placed two faucet washers, the 1/4" thick type, in the two bottom hinge holes. I did not put one in the top hinge hole. Then, I tightened down the bottom screws to compress the washers, which provided adjustability to the clearance. The top washerless screw provided another bit of adjustability. It is very stable and now JUST clears the arm when it is at rest. A fine conclusion to a Summer Audio Weekend. Hope you all have the same! Best regards, Dave ------------------ David A. Mallett Average system component age: 30 years. Performance: Timeless Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted June 26, 2002 Share Posted June 26, 2002 One other thing to consider here about the sweet spot location...if you are using k-horns, you are limited to an angle of fire out of that corner of 45 degrees ONLY, unless you build false corners so that you can toe that angle outward or inward to adjust that sweet spot....OR...move the speakers closer together and have a false wall come out to supply the rest of the needed corner. Non corner horns...don't have this problem, they can just be toed in or out as need be. Another thing you have to remember is that Horn-loaded speakers have a NARROWER dispersion radius than Cone speakers, which results in greater directivity, but less width of dispersion.....this is because the sound is channeled down a horn lens instead of just radiating out....the same reason the horn gives more decibels of SPL....within that dispersion radius. Sooooo....this makes the sweet spot smaller...in other words, it doesn't extend as far forward, or rearward....neither does it extend as far from side to side...as it would on a cone loaded or dome loaded speaker. BUT, that same narrowness of dispersion also makes it VERY easy to find that sweet spot just by walking back and forth out from the center of the wall the speakers are in the corner of...you will HEAR the sweet spot! This message has been edited by HDBRbuilder on 06-26-2002 at 12:45 PM Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted June 26, 2002 Share Posted June 26, 2002 Ed, that IS where your sweet spot would have to be considering where your speakers are pointing, in this case with Khorns, as HDBR notes, is limited if back in the corners flush. Obviously, to get the sweet spot back to more a proportional location, you would have to change the angle of the Khorns....or end up moving your listening chair to the forward location, which is not the optimum. The long wall-short wall problem is really a matter of where you can be situated. Seems to me, the best wall length would enable you to establish a sweet spot that is correct with the equilateral triangle. On the other hand, many horn users are finding it advantageous to cross the axis in front of the listener. I have seen this reported time and time again. I have found my Cornwalls to work the best following the basic equilateral triangle method. I also do not like the idea of a center speaker at all. In my view, this actually corrupts a proper soundstage. Of course, there are a good portion of forum members here that dont find imaging or soundstage capability to something to even consider. It's all in preferences. Having the speakers in the corners surely does not do wonders for soundstage depth. AGain, personal preference. At least the Klipsch horns do a much better job in the corners than the average dynamic speakers. My ProAcs like to be WAY out in the room. kh ------------------ Phono Linn Sondek LP-12 Valhalla / Linn Basic Plus / Sumiko Blue Point CD Player Rega Planet Preamp Cary Audio SLP-70 w/Phono Modified Amplifier Welborne Labs 2A3 Moondog Monoblocks Cable DIYCable Superlative / Twisted Cross Connect Speaker 1977 Klipsch Cornwall I w/Alnico & Type B Crossover Links system one online / alternate components / Asylum Listing f>s> Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted June 26, 2002 Share Posted June 26, 2002 Ed, thanks for chiming in there ... I was a little lost on the equilateral triangle proposal, since Khorns automatically bisect the corners' 90 degree angles into two 45's. With the perpendicular line from the center of the long wall being 90 degrees, the remaining angle has to be 45 degrees to sum all the internal angles at 180. Therefore what we have are two isosceles triangles (45/45/90) with a common side (the perpendicular line bisecting the long wall and crossing the listener's position). In essence, all we need to do is put these Khorns in gymnasiums and we'd be golden ------------------ "Bullsh*t!" -PWK- --------------------- TWO-CHANNEL SYSTEM Eico HF-81 Eico HFT-90 New Tube 4000 CD Player 1976 Klipschorns (KCBR's & ALK'ed) HOME THEATER Klipsch 1968 ALK Cornwall "II"s (LF/RF) ALK Belle Klipsch (Center) Klipsch Heresy (RR/LR) Klipsch KSW-12 sub Sonic Frontiers Anthem AMP1 (driving Cornwalls) Sonic Frontiers Anthem AMP1 (driving Heresy's) Denon AVR-4800 Toshiba SD-3109 DVD Quote Link to comment Share on other sites More sharing options...
Randy Bey Posted June 26, 2002 Share Posted June 26, 2002 Gee, so much discussion. This is almost too easy to be worth the effort. My room is 19'x15' (more or less) with the Khorns on the long wall. Can't put 'em on the short wall due to a radiator in the corner. I position my listening seat so that I am equidistant from both speakers, and able to look the tweeter square in the eye when I turn my head to face either horn. It's not an equilateral triangle, as someone mentioned, but rather isoceles. And I have no 'hole' in imaging whatsoever, despite such a large front wall. I have tried moving the listening position behind the 'sweet spot' but didn't warm to the sound. Dead spot on between them there is a range of detail just not perceivable elsewhere. That's my 2c worth anyway. Quote Link to comment Share on other sites More sharing options...
Mallette Posted June 26, 2002 Author Share Posted June 26, 2002 Isn't it nice when what you've got floats your boat in spite of theory? Dave ------------------ David A. Mallett Average system component age: 30 years. Performance: Timeless Quote Link to comment Share on other sites More sharing options...
mobile homeless Posted June 26, 2002 Share Posted June 26, 2002 Not sure what that means but if you got a HOLE in the middle of your soundfield, that aint good. I find this impossible to live with, even for five minutes. There is nothing worse that the sound appearing as if it's coming from your speakers with no center fill. HAving a third speaker is not my idea of a solution either. Any other placement options? kh Quote Link to comment Share on other sites More sharing options...
Mallette Posted June 26, 2002 Author Share Posted June 26, 2002 You seem dead convinced that PWK and Bell Labs were totally wrong about the center channel concept. Certainly has become established in HT apps. Granted, that's not music, but I've heard music mixed for it that was quite nice. Anyway, I've no placement options at the moment without returning to the living room, and I'd rather live with weak staging (there is no "hole"...just not precise positioning). Since I listen to lots of pipe organ, symphonies, big band, and 78s that have little or no precise positioning anyway, I can live with it as opposed to having to battle with the HT. Might try toeing them in a bit just as an experiment to insure that I really CAN live with it for a while. If I am so overwhelmed with the improvement in staging that I can't live without it, false wall would be the route. BTW, what is the SIMPLEST (even if not ideal) false wall method? Dave ------------------ David A. Mallett Average system component age: 30 years. Performance: Timeless Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted June 26, 2002 Share Posted June 26, 2002 Oooh ... I think Edster is the current reigning champ on false wall construction. Basically, a few slabs of something rigid, either a 2x4 wall, per the included URL, or a few nice joined pieces of 1" marble (LOL): http://216.37.9.58/ubb/uploads/Chris+Robinson/FalseCorners.jpg Quote Link to comment Share on other sites More sharing options...
edster00 Posted June 26, 2002 Share Posted June 26, 2002 Okay, now I am more confuseder than I was before. If my sweet spot is at the equilateral triangle thingy I don't really need false corners. If the sweet spot is at the isoceles triangle I want to use false corners to move the sweet spot farther into the room. Ever since I got the K-horns I have angled them into the room and have some DIY MDF backs (poor man's false corners) that don't extend far enough out and aren't well braced but still sound pretty good for what it is. I am really looking forward to finishing this room off and having some proper corners whether they are real or false. I don't think this thread could get much farther off topic...maybe I should start a new thread?? This message has been edited by edster00 on 06-26-2002 at 03:54 PM Quote Link to comment Share on other sites More sharing options...
Chris Robinson Posted June 26, 2002 Share Posted June 26, 2002 Ed, no need to start a new thread. Simply put, if you're using Khorns, the two speakers and the sweet spot create an isosceles triangle, therefore you will need false corners. Proceed as planned, I'd say! CR Quote Link to comment Share on other sites More sharing options...
HDBRbuilder Posted June 26, 2002 Share Posted June 26, 2002 ED, RE: your drawing Your black lines are an isosceles triangle...and that IS where the centerline of the k-horns is...at the apex of that ISOSCLES triangle...BUT... That point is ALSO where the "hole" begins...AND... AT that point and anywhere forward of that point...the imaging begins to creep farther and farther around to each side, thereby leaving a larger and larger "hole" to the front center...BUT... ANYWHERE FARTHER AWAY from that point has the imaging creeping more toward the center of the front wall...and LESS from around your sides....and that is where you WANT the imaging to BE...ACROSS YOUR FRONT, but not gathered up in the center...does that make sense? By using the red lines, which are the equilateral triangle...you automatically place the imaging across your front, and not around to your sides...GUARANTEED!..NO DOUBT ABOUT IT....with the ADDED BENEFIT of not being OVERPOWERED by having those horns fire DIRECTLY at you...but ever so slightly across your front...thereby eliminating the "harshness" some people mention about horn-loading...and still allowing for the best imaging and soundstage from just two k-horns.... IOW...the sweet spot isn't supposed to be directly on the center axis of fire of the k-horns...but just beyond it, farther out from that front wall...thereby the equilateral triangle INSTEAD of the isosceles...understand now? This method gives you everything wanted...it eliminates harshness, gives proper soundstaging and imaging ACROSS YOUR FRONT, instead of WRAPPED around your SIDES....and provides a much more pleasant listening experience. When you add a center channel to this, it allows for that center channel(providing it is a match to the front left and right speakers)to BLEND across the front...AND to provide more FILL , thus enlarging the AREA in which stereo effect will be heard in the room. I hope this finally clears this up. PWK knew this...and that is why he was a proponent of the center channel.....TO PROVIDE AN ENLARGING OF THE ROOM AREA IN WHICH STEREO IMAGING WOULD BE HEARD...that is all!! He did NOT intend for the center channel to be used to fill a "hole"...JUST to enlarge the AREA in the room in which stereo imaging best occurs. It works, too! ------------------ I can now receive private messages Quote Link to comment Share on other sites More sharing options...
J M O N Posted June 26, 2002 Share Posted June 26, 2002 Dave, Are you sure you measured that wall correctly. I seem to remember it being at least 35-40 feet. Quote Link to comment Share on other sites More sharing options...
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