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Chris A

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  1. This issue of "screening" is always a source of problems in decision support models (and I've done a lot of those models over my career). Screening of participants and other data sources is also a sure-fire way to spot confirmation bias tendencies. One of the techniques that is used by QFD professionals (Quality Function Deployment) is a "customer segmentation matrix". The following notional (i.e., non-calibrated) matrix is for home theater audio customers: The left-hand column has the identified customer segment types. The customer segments are usually identified via affinity analysis of interview data. The needs of the nine (9) identified customer segments in the notional example differ according to the desired/required product attributes in this case. Kano product analysis tags (B, O, A) and Christensen Product Hiring model attributes (GB, ETB, ETU, LP) are also included in the "Hows" across the top of this matrix. All of the above is provided as a cursory example only--that the analysis done by Olive, et al., is much too much focused on "getting the corporate answer" than "getting the truth". If Olive had instead hired himself a QFD professional before starting his big decision model, he would have gotten much different results (and he may have, and was later directed by corporate upper management to change his results in order to advertise their work for corporate benefit). I've seen this issue a million times (it seems ) as a practicing operations analyst for many years, and as a QFD practitioner for even more years. Chris
  2. Continuing with this line of inquiry, it seems to me that there are people that are listening to something quite different than flat phase/SPL direct radiating loudspeakers for a reason. The iconic example of this phenomenon is the Khorn and the people that love them, in my view. (There are other offshoot listener groups, such as those that prefer "full range drivers", planar dipoles, quasi-omnidirectional, and even more design types.) These groups of listeners eschew the typical monkey coffin designs that have been discussed, above. So what is unique about the Khorn lovers? The first set of factors (#s 1-7 above). Even to the point of dropping the requirements of the following three requirements (FR flatness, impulse response, electrical impedance), these people are quite happy with what they've got. Especially when they achieve a good listening environment and have found a way to equalize the on-axis frequency response somewhat using amplifiers, preamps, and the like. Some Khorn owners go further: they replace the midrange horns/drivers and even the tweeters, crossovers (including Zobel networks to tame the input impedance swings in output SPL when using high output impedance amplifiers), and false corners/enclosed backs, etc. What's most important to note, however, is that for the people that don't change their Khorns to do these "enhancements" (changes), the existing performance of the Khorn is enough for them. This means that the loudspeaker requirements set and their relative importance are not monolithic from all listeners, as Olive/Toole would have you believe. There are significant groups of listeners that have been systematically screened out of the group that Harman performed in its "listener qualification" trials that resulted in their final reported requirements precedence(s). "So what?" There are obviously large variations in what people prefer and listen for. In the case of the Khorn, we have a body of technical papers and articles that explain these differences (low modulation distortion, higher efficiency, full-range directivity, etc.). Atkinson, et al. have also tried to screen these type of listeners out--and to glom onto the "Harman bandwagon" in that regard. The interesting thing is (anecdotally)--this group of Khorn listeners also tends to include professional musicians (formally trained, etc.). Now isn't it interesting why that might be the case? Chris
  3. Most people that own them do--as well as quite a few that don't yet own them but wish that they did--along with a listening room that does them justice. I think that the recent magazine article writers forgot that. Richard Heyser didn't, however. Since Heyser's Khorn review in 1986, things have changed, most notably the ability of virtually anyone to measure their own loudspeakers in-room using even more powerful measurement means--and that the cost of these measurement instruments is now free (except for the cost of the personal computer that most people already have amortized for other purposes than measuring loudspeakers, and the cost of a "good enough" calibrated microphone that costs ~100). This is probably 1% or less of the de-inflated cost of the equipment that Heyser used in 1986. The Khorn wasn't designed by committee: it was designed by PWK (recently updated by Roy D, et al.). All loudspeaker designs represent compromise. It's how those compromises are determined that makes all the difference. If you use the requirements sets and their relative importance promulgated by Atkinson, et al., you tend to get the same results...that all sound about the same. If instead you recognize that there are people walking around that say that they much prefer the sound of Khorns to those many thousands of "monkey coffin" designs praised by Atkinson, et al., then you have the opportunity to learn something new by examining why that is. Chris
  4. It's my premise that the gentleman that you identified knows what he is doing, but that his motives are less than stellar. I don't like what he is doing--it's dishonest. It is my belief that the reason why this thread is here and is growing is that discussing the review really does matter. Talking in depth about the review in a systemic manner rather than just taking poorly aimed pot shots I think is important. And attempting to summarily dismiss this discussion is something that I find to be uncalled for and unfair. I believe that this type of magazine review does unnecessary harm to Klipsch's products--particularly the Khorn. I think that's a pretty important subject, actually. I think that it's not such a mystery. (You probably do, too.) The reason why I took the time to write what I did--and it took a while to cobble together what I wrote--is that I believe what the magazine did does a great disservice to Klipsch and others that might feel that the Khorn has been almost a singular example of rebutting the easy opinions expressed by this magazine. PWK spent a significant effort rebutting these sort of "drive by" reviews, and also leading by example in his loudspeaker designs and educating his customers and his own staff. So it does matter because there are a lot of people out there (as evidenced by some of the responses here) that don't have enough information to separate the truth from assumptions, and that they actually take the words of a magazine that hasn't done it (and probably can't do it) over the words of those that have (Klipsch). The point of talking about precedence of requirements in loudspeaker design is I believe important--so much so that I intend to extend the discussion to Jubilees and perhaps other closely aligned loudspeaker designs. Mine don't, but then again I've spent time getting to know them better via testing, updating settings, changing in-room configurations, and experimenting with different room acoustic treatments in order to significantly improve their acoustic performance. This work over the past 5 years is the basis of the above discussion on precedence of loudspeaker requirements. I'm very familiar with this work by Sean Olive--and championed by Toole. There are some real issues there that ultimately benefit Harman and its current product lines. I'll wait on those discussions. Just note that there are reasons to not believe the requirements precedence that Toole apparently pushes, and that it is quite easy to rebut. Chris
  5. One of the great missing links to the loudspeaker engineering repertoire (IMO) is a ranking of loudspeaker performance attributes by measurement type--not based on someone's opinion of what is important, but rather by subjective preference by listener groups on particular loudspeaker types (by listening group preferences), and then an analysis of how the most preferred loudspeakers actually performed, i.e., an approach that is reversed from the engineering literature on loudspeaker measurements. The following loudspeaker capabilities types are presented from a notable writer on this subject--Joseph D'Appolito (author of Testing Loudspeakers (1998, Audio Amateur Press) an excellent resource for learning about these measurements and what they mean), based on "30 years of designing loudspeakers". What he didn't mention was that virtually all of these loudspeaker types are direct radiating types, using cone and dome-type drivers in a "monkey coffin" type of small enclosure, with no precedence given within the group: Frequency response Impulse response Cumulative spectral decay Polar response Step response Impedance Efficiency/Sensitivity Distortion Dynamics Rearranging the above and expanding the list to include some missing measurements, the following list of revealed capabilities based on the Khorn's performance in each of the measured areas: Full-range directivity (particularly below 800 Hz) Modulation Distortion Compression Distortion Efficiency/Sensitivity Cumulative spectral decay (especially below 800 Hz) Room dimensions/loudspeaker placement Near-field room absorption around loudspeakers The following list of loudspeaker capabilities are significantly depreciated with regard to those preferring the Khorn's sound reproduction: Frequency response flatness (particularly below 200 Hz) Impulse response Input Electrical Impedance ___________________________________________________________________________ Each of the above seven capabilities have associated measurements: Directivity -- measured via multiple upsweeps with microphone at a set radial distance from centerline of loudspeaker, usually in 10-15 degree lateral and vertical increments, combined into a "polar spectrogram" view, i.e., 2. Modulation distortion -- measured via dual-tone test, looking at the relative amplitude of the sideband spikes around 450 Hz in this instance: 3. Compression distortion -- measured via multiple on-axis upsweeps at increasing SPL (trace arithmetic 75 dB [blue trace] overlaid on 100 dB [red]): 4. Efficiency/Sensitivity -- measured by calibrated output to a given calibrated input power or voltage level (looks just like an on-axis SPL/frequency plot) 5. Cumulative Spectral Decay -- measured by waterfall plot: 6. Room Acoustics/Loudspeaker Placement -- measured via Energy-Time Curve (ETC) plot (which also shows room acoustics performance): 7. Near-field room absorption around loudspeakers -- measured early decay time (EDT): The point to showing these example plots is that the real measurements that make a difference to those people that prefer the sound of Khorns and other Heritage Klipsch loudspeakers--aren't found in Mr. Atkinson's measurements for his magazine. In effect, he's saying "one size fits all, and my measurements are important, but the ones that you want to see, well, good luck...I'm not going to post that data". So the value of the magazine review is, in effect, zero--because the people setting up the loudspeakers in their selected room (which apparently was a poor room to use as an example for a good installation of Khorns) and the measurements that the technical editor wants to post...simply do not represent what you need to see and hear if you were a prospective Khorn buyer. The entire article is a waste of everyone's time. Chris
  6. I believe that it does. If you remember Greg Oshiro's thread from 2011, his impressions after tri-amping and dialing everything in (Greg works in the industry and was the inspiration for me to go ahead and start using REW and a more capable DSP crossover than the EV Dx38 that I was using): I would think that a turn-key Khorn DSP crossover tri-amp kit would include something like a Xilica XP4080 or XP8080 (or miniDSP 4x10 HD if you want to go the least expensive route), six channels of amplification--such as three stereo amplifiers--and associated cables. The DSP settings can be found in Greg's Khorn tri-amping FAQ on page 2, linked above. Since the Khorn was PWK's baby (and he isn't around to give his blessing to doing a DSP crossover kit), I think that there's resistance to the idea of Klipsch providing a DSP crossover tri-amping kit, but I believe that it would be a fairly big seller if it were offered by Klipsch. As it stands, anyone that wants to DIY can tap into the existing support sound here on the forum. It costs nothing for the dialing in process--all you have to do is get REW up and running and take some measurements, then email the measurement files to Chris A ("yours truly", as well as any others having DSP crossover experience), whereby you get configuration files emailed back to you for immediate import into XConsole (Xilica) or the equivalent miniDSP application for the 4x10 HD. How to integrate a DSP processor into your system: The success and satisfaction rates have been very near 100%. "Bang-for-buck" is higher than any other upgrade that can be accomplished with Khorns and it facilitates the swapping out of midrange and tweeter horns/drivers without the usual resulting issues of crossover problems--the DSP crossover is waiting for you to make those changes--without added cost or significant effort. Chris
  7. Toccata in D Minor (Dorian), BWV 538 by J.S. Bach Another one of my Bach organ favorites. The fugue that goes with this is even better, IMHO. If you go look up the musical modes (i.e., "church modes"), you will see a history of music that will open up to you a new world of music that extends back to at least ancient Greek (Athenian) civilization (~400 BC) whereby some of the musical modes are ascribed to psychological "goodness", other modes to less useful (militarily and patriotically) music. The following quote is taken from here: Aristotle continues by describing the effects of rhythm, and concludes about the combined effect of rhythm and harmonia (viii:1340b:10–13): From all this it is clear that music is capable of creating a particular quality of character [ἦθος] in the soul, and if it can do that, it is plain that it should be made use of, and that the young should be educated in it. (Barker & 1984–89, 1:176) The word ethos (ἦθος) in this context means "moral character", and Greek ethos theory concerns the ways that music can convey, foster, and even generate ethical states (Anderson and Mathiesen 2001). Well--there it is: the first mention of "musical propaganda". Chris
  8. The people at the magazine are taking hits in the comments section of the posted article at their own web site. I wouldn't want to be in either of those guy's shoes right now. I'll let my first impressions stand. It now looks as if the magazine now appears to have done a review that's either 1) a fiasco (i.e., incompetent), or 2) these two guys were "spring-loaded" in advance. Atkinson really just did a huge reputational damage to himself, I believe. Richard Heyser did an excellent review and produced tons of useful information--even considering that more than 33 years have elapsed. Roy's upgrade of the passive crossover in the Khorn and the new tweeter driver and tractrix horn are likely extremely well done. If I had to believe one person, it's not difficult for me to take sides. Roy also had access to an anechoic chamber that was constructed with the aim of being able to specifically test Khorns. Which one would you believe? Chris
  9. It's generally better to place the mouths of all the horns near the same vertical plane, and correct the delays using a DSP crossover. This will get you time alignment at large lateral off-axis listening angles, e.g.: Putting the mouths of the horns at set back positions to match the acoustic centers of each horn/driver physically (à la Avantgarde Trio style) actually creates issues with horn mouth obscurations off-axis or excessive lobing within the sound field due to the exaggerated vertical and lateral spacing of the different "ways" of the loudspeakers. Also, the time alignment shifts as you move more and more off-axis. This forces the listening of these type of loudspeakers on-axis, very much like older audiophile systems having a limitation of where you listen to them in-room: Commercial cinema loudspeakers must have sweet spots as large as the auditorium seating that they cover--eliminating the archaic audiophile need for "sweet spot listening". The only limitation is stereo listening, whereby in order to get a balanced phantom center image, you must be sitting on centerline between the left and right loudspeaker arrays (which is a limitation of stereo recording and playback itself). In multichannel soundtrack and music playback, loudspeakers designed for commercial cinema must make every seat in the house a viable listening position, locking in the center of the acoustic image using loudspeaker arrays of 5.1+ loudspeakers. Chris
  10. Well, since the Xilica can delay up to 650 ms per channel, that equates to 735 feet of set back of the K-402s that's available to you. Practically, it means that if you can hear and see the K-402 in the venue from standing at the SMWM bin, you can correct the relative time delay on-axis. (Large off-axis time alignment is another issue, however... 🙂) Remember that the Xilica is a professional crossover, i.e., not a consumer device, so the issues of arena and stadium installation time alignments is very much a real application of that large value of delay capability that's available with the XP and XD series crossovers. Chris
  11. I believe that if you read carefully, Dudley was talking about the front face of the Khorn from the front wall. That makes a little difference--about 2 feet worth of difference, to be more exact. However, I've found that you need to have the bass bins well within 12" (~30 cm) of the corner seam of the room (or wall/backstop...such as a large tapped horn subwoofer as I have in my setup) to avoid midbass frequency response issues and added phase/group delay response issues. Not having a picture of his room with Khorns and placement them WRT the room corners with the acoustic treatments being used to control the midrange floor/ceiling bounce issues...this is an error on Stereophile's part. People who are considering buying Khorns should immediately be able to see this, not have to imagine it in their mind's eye... Chris
  12. It doesn't appear that you have the required room depth or depth of seating locations to take advantage of the "VBAT" bipole polar coverage capability. All you will achieve is more front and back wall bounce using VBAT models (which isn't really desirable). I'd instead recommend something that covers your prime seating position well, and has approximately the same timbre and end-to-end frequency response as your fronts--such as this: https://f072605def1c9a5ef179-a0bc3fbf1884fc0965506ae2b946e1cd.ssl.cf2.rackcdn.com/product-specsheets/KPT-325-Data-Sheet-v04.pdf or this: https://f072605def1c9a5ef179-a0bc3fbf1884fc0965506ae2b946e1cd.ssl.cf2.rackcdn.com/product-specsheets/KPT-396-Data-Sheet-v06.pdf The surround height above the sitting position should be pretty much like your fronts as specified in the 5.1 ITU-R BS.775–3 arrangement: Chris
  13. After reading the review, I have to say that it certainly appears halfhearted, looking at Mr. Atkinson's "measurements". He knows that the Klipschorn requires a room corner to complete the bass extension, yet he has Dudley drag one of them out on his driveway to measure frequency response...(?) Is this merely poor judgment or lack of interest in doing a good job? I do see the focus on step response and highlighting the large time misalignments inherent in the Khorn, but that review was written 33 years ago by Richard Heyser in Audio magazine, which I assume they had a copy of. Heyser did an excellent review--33 years ago--but it appears that Atkinson hasn't learned much new about corner horn loudspeakers since. EDIT: you can find a slightly better reproduced version of the Heyser Khorn review in this pdf file, starting on the 66th page of the file: https://www.americanradiohistory.com/Archive-Audio/80s/Audio-1986-11.pdf Turning to Mr. Dudley's portions of this review: his apparent difficulties and poor decisionmaking regarding amplifiers and room/corner position extended to him never posting a picture of his final Khorn room placement. It doesn't appear to me that he ever got the Khorns to sound good in his listening room. It also appears that he thinks that connecting high dollar tube amplifiers will solve his room and room placement problems (most importantly--frequency response issues), which is an amateur's mistake. For a magazine that purports itself to be the voice of experience and technical understanding of loudspeakers and room acoustics, translating complicated reality into something that its readers can grasp--it didn't succeed here. It appears that they can't continue to learn about their problem domain...after all these years. Burnout? Thank goodness they didn't try to review a Jubilee. I can see Mr Atkinson now, trying to attach accelerometers to the bass bin...somewhere. Chris
  14. The posted review of the Klipschorn AK6: https://www.stereophile.com/content/klipsch-klipschorn-ak6-loudspeaker Chris
  15. Yes. As the compression slot or throat dimensions get close to 1/2 wavelength of the emitted acoustic energy, the restriction or expansion will begin to strongly interact with the emitted acoustic output. You can think of these slots like phase plugs in compression drivers--the plugs are there to prevent cancellations across the diameter of the diaphragm and throat exit. Here is a plot of what a phase plug does to extend HF performance in a compression driver/horn assembly (horizontal axis = normalized frequency, vertical axis ~relative SPL): As the design of the phase plug gets better and better, the smoother the resulting frequency response at higher frequencies. When you suddenly constrict or expand the throat of the compression driver/horn interface, the resulting frequency response begins to get very ragged at higher frequencies. You also begin to see the effects of all that reflected acoustic energy at those drop-out frequencies interact with the compression driver diaphragm, which cause all kinds of harmonic and other distortion types to be generated. Chris
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