Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/3/84; site teddy.UUCP Path: utzoo!linus!philabs!cmcl2!seismo!harvard!talcott!panda!teddy!rdp From: rdp@teddy.UUCP Newsgroups: net.audio Subject: Re: RAW SPEAKERS Message-ID: <1134@teddy.UUCP> Date: Tue, 13-Aug-85 13:48:01 EDT Article-I.D.: teddy.1134 Posted: Tue Aug 13 13:48:01 1985 Date-Received: Thu, 15-Aug-85 08:24:57 EDT References: <3177@decwrl.UUCP> <975@teddy.UUCP> <914@druxo.UUCP> <988@teddy.UUCP> <334@ttrdc.UUCP> Reply-To: rdp@teddy.UUCP (Richard D. Pierce) Organization: GenRad, Inc., Concord, Mass. Lines: 129 [] In article <334@ttrdc.UUCP> kyl@ttrdc.UUCP (Kwing Y. Lee) writes: >Dick: > > When I first purchased the Klipsch speakers time and phase coherence were >just started to be the main design goals of speakers (Dalquist DQ10s). Back then >the criticisms that I heard about the Klipsches are that they are too big, too >expensive and they don't have the high end response that they should have.... >and also the so called "horn sound". Now nearly 10 years later, I still have not >outgrown by babies and I still think they sound fantastic. I would really >appreciated if you can summarized all the criticisms of Klipsch horn speaker >systems in one single comprehensive article. Thanks in advance. > > Kwing Ok, I will try. First of all, let me say that, as far a cabinetry goes, I cannot impune the manufacturers at all. The Klipsch K-horns ARE solidly built, well fitted, nicely finished, and, for something that large and awkward, are attractive in there own occasionally endearing way. And I cannot find a single chink in the armor of its progenitor, Paul Klipsch. However... The prime advantage to K-horns, and things of the horn genre is efficiency. If that is the prime criteria, then I can have no objections. Horns, realized in a practical manner, have real problems. First, the K-horn bass driver (as I can recall) is a fairly old style EV woofer, specifically designed for direct radiator use, albeit that alone does not acount for most of the problems. The bass enclosure, a severely folded horn, is, at best, a compromise. It is only a rough approximation of an exponential taper, and therefore cannot provide a continuous match along its path to the final load, the room. This causes problems such as internal reflections, cancellations, what have you. The sharp bends also cause reflection problems, as well as non-linear attenuations at the what might be considered only moderately high frequencies for a straight horn. At the the throat of the horn, measured particle velocities are high enough to cause non-linearities in propogation characteristics. Add also the fact that there is a many millisecond delay, which changes non-linearly with frequency. The net result is that the bass section has (as a measured fact) a very ragged frequency response, which has been shown by some researchers to level dependent. Mr. Klipsch continuously raises the spectre of "Doppler distortion" as the bugaboo of all direct radiator designs, yet all of the research papers I have been able to collect are, at best, confusingly undecided in total about either the existance or the detectability of such distortion. (H. D. Harwood, in the early 70's published an article which both philosophically and experimentally dealt a severe blow to Klipsch's assertions. I will try to resurect it if desired). Note also that because K-horns need the entire room to attempt to couple properly, they can be far more room dependent than direct radiator designs, judiciously placed. The mid-range and treble drivers are fairly mundane straight exponential horn designs, nothing great, nothing terribly bad. However, Klipsch makes the same, to me, very stupid mistake when it comes to orrientation. The best, most uniform and frequency-independent dispersion occurs at right angles to the long dimension of the horn. This means that in the Klipsch, where the long dimension is horizontal, the best dispersion pattern is vertical!. The measured dispersion characteristics of the speaker are truly dismal in the 1000 Hz and up regions of tghe spectrum. I will concede, however, the impracticality of re-orienting the drivers on such an already huge cabinet. The crossover is fairly simple-minded and straightforward, and that may, in fact, be it's saving grace! But.. Because of the tremendous phase and delay anomolies at the various crosover points, both the response characteristics and the dispersion characteristics at those frequencies are truly bizzarre! Since the indtroduction of more sophisticated measurement techniques, the measured characteristics of the speakers have been even stranger than even I would imagine. IMpulse response is very poor. The speaker has been measured with incredible long decay times, complex rise characetristics, and truly non-linear and non-minimal phase characteristics. Now, be that all as it may, SO WHAT, you say. I am also a musician of sorts (more a listener, though), as well as a reasonably accomplished instrument builder (I have built 11 harpsichords or clavichords, 2 small portative organ, one positive organ, and have repaired and restored many instruments ranging in age up to 300 years). Simply stated, music played on instruments that I am familiar with are reproduced very unfaithfully on Klipsh loudspeakers. Harpsichord music looses completely any hint of clarity, inner voices are completely muddled, and the higher registers are at once both very brittle and muddy. Organ music, recorded properly looses all of the "pipe noises" that can be easily heard in person and on other speakers of less technological pretention. Yes, K-horns certainly do play very loud, but so what? The kind of music I listen too, and the vast majority of classical music can be more accurately reproduced on lower effeiciency speakers of demonstrably higher fidelity. The efficiency and dynamic range arguments put forth by many horn proponents are not supportable, given the REAL requirements of reproducing music. The exception might be for rock, where sheer acoustic power is needed to replicate the effect of a "live" concert, but here we have no live analog to compare against anyway. Most proffesional PA systems are so much worse than K-horns or any other home speaker as to be laughable. (I once designed and built a set of high-power PA speakers for a rock band. They were VERY good. They were smooth, low distortion, wide bandwidth, etc. Nobody liked them.) Now, do I object to you liking your Klipsches. No, absolutely not. What I object to is their inability to faithfully reproduce musical sounds that I know well, in comparison to many other loudspeakers. I object to statements, such as one of the ones that followed your article, that "horn sound" is smooth, uncolored, low distortion. On an objective basis, K horns and most comercially available horns are neither smooth, uncolored or low distortion. At least two of those quantities can be measured objectively, and the horns fail both very miserably. I will concede that K-horns are probably the best, most practical commercial realization of a horn intended for home use. It's just that horn aren't very good. But then again, I like Harpsichord music by Francois Couperin, so I must be nuts anyway. Regards.. Dick Pierce