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Chris A

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About Chris A

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    Music Enthusiast

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    Arlington, Texas, USA
  • Interests
    Small room acoustics, acoustic measurement, acoustic horn design (including multiple entry horns), sound reproduction system design, and source music remastering (restoring/rebalancing music tracks).
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  1. PBS documentary "Soundbreaking"

    I do recommend the PBS series on Amazon Prime Video called "First Peoples". There's some truly new stuff in those episodes. Chris
  2. PBS documentary "Soundbreaking"

    Amazon has the Blu-Ray version for $22. I bought the disc and have since watched them. If I had to mention anything...it's that its scope is a" just a wee bit narrow", especially if the advertised subject is The Cutting Edge of Recorded Music. I'd expect that sort of thing from Rolling Stone magazine of which this series strongly reminds me of the book 1001 Albums You Must Hear Before You Die. There are some trips down memory lane, but nothing really new...or worth $22. I actually expected a much more balanced series from PBS. I think that Ken Burns would have done a better job covering the mostly historical subjects. I suppose we live in an age of "feel good nostalgia" when it comes to music. Chris
  3. Klipschorns In A Small'ish Room

    This is another topic of angst I believe: the K-77 tweeter relative to other tweeters/horns that are available nowadays. In the heyday of the Klipsch Heritage line (1950s-1970s), the K-77 was probably the best choice for its performance, cost, reliability and overall size/shape. However, as time marched on, the K-77 really became probably not the best tweeter. I found this out when I tri-amped my center Belle and found a certain sensitivity of the high frequency sound to the exact crossover settings used in the DSP crossover. I found that the high end of the K-55 driver with its horn was allowed to acoustically roll off in the stock passive crossover without an electrical low pass crossover filter to positively roll-off its high end. During this time I found that the K-55 needs to be rolled off using a crossover filter in order to produce the best sound. In addition, the K-77 sounds very ragged if crossed below about 4.5-5 kHz, and that--using a fairly steep slope filter of the type which also detrimentally adds to the phase mismatch at the crossover band between the midrange and tweeter. I played around with the active crossover settings, but I found that the tweeter and midrange really had almost no adjustability in overlap point and bandwidth in their crossover bands. I found that the crossover needed to be right at 4.9 kHz, no lower and no higher, and that the steepness of the crossover filters was higher than I wanted in order to control the phase growth of the tweeter-to-midrange transition. So I substituted in a Beyma CP25 "baby cheek" tweeter, and found that I could lower the crossover frequency and the order of the crossover filter to improve the overall sound. This was a fairly audible improvement. Later on, I swapped out the K-55/K-500 horn for a K-510/K-69-A driver, and moved the crossover frequency up to 8 kHz. The in-room sound quality improved significantly; the results of the crossover settings were posted to this thread. In summary, I too found that some simple swapping out of the midrange and tweeter horns/drivers had a fairly strong effect on the sound quality and apparent source width (ASW) of the Heritage series loudspeakers. YMMV. Chris
  4. Klipschorns In A Small'ish Room

    If you don't have a room that can easily accommodate Khorns (and there are a lot of those) then you usually wind up having them too close together or too close to the listening position(s). In either case, they usually have a visual presence that is a bit too obtrusive for the female gender. Khorn acoustic performance in very small rooms is also not anything like putting them into better-sized rooms. I've always wondered how large the home listening rooms of PWK were over time. In the 40s and 50s before stereo recordings hit the marketplace, I'd assume that almost any room with a good available corner was sufficient for a mono Khorn. Rooms in the first suburban homes for working folks tended to be very small rooms. But as the 1960s rolled in with stereo recordings as the default format, rooms also tended to get much larger in the USA. I note that PWK's last listening room didn't have two good corners, so he used false corners, but it looked to be large enough to fully accommodate the Khorns. Nowadays, there is an entire generation of young people that have had to step back from the larger homes of the 60s-90s, and now largely live in apartments and other rented properties, waiting for the day when they might afford to own their own home and perhaps have the job stability to buy into a geographic location without fear of having to move again too soon to justify the buy-in. I think that limits the sales of corner horns of the performance of Khorns, instead favoring La Scala or Belle-sized loudspeakers in stereo pairs with their one-octave-higher bass cutoff frequencies--but themselves still imposing in very small rooms. I think those facts have always been a source of angst in threads like this one when talking about Khorns vs. La Scalas/Belles. Chris
  5. Klipschorns In A Small'ish Room

    No, not sarcasm. The footprint (as was mentioned in the quoted text) of the Khorn is actually much less invasive in-room. The height of the Khorn is obviously not as small, but in my experience most people are looking for ways to get the tweeter up to the level of the ears while the listeners are seated...even to the point of sacrificing midbass and low bass performance by raising the loudspeakers off the floor, which always produces nasty midbass frequency suck-outs. The Khorn needs no such risers. Chris
  6. Klipschorns In A Small'ish Room

    Yes...same midrange driver/horn and same tweeter in the La Scala as the Khorn. This aligns the tweeter to the midrange. There is a several wavelength mismatch between these two drivers/horns at their crossover frequency (about 4-6 kHz) which is the most audible in both loudspeaker types. By tri-amping and setting the correct time delays (using a DSP crossover) on both the midrange and tweeter channels, you can also align them both to the bass bin at ~400 Hz. There is a much smaller relative phase/time delay between the midrange/tweeter horns and the bass bin horns than in the midrange/tweeter crossover due to the 10X difference in the wavelengths. Chris
  7. Klipschorns In A Small'ish Room

    True... If you release and move the tweeters to the back of the top hat on top to time align them to the midrange drivers, your minimum listening distance issues in small rooms will be dramatically reduced. It's cheap, easy, and reversible to listen to the difference. Tri-amping and time-aligning them will be even better... You can also place some soft fuzzy material across the top of the top hats and make sure that there is plenty of absorption covering the floor in front of each Khorn...which controls the midrange ceiling and floor bounce better between 400-2000 Hz, then I believe that you will find that having Khorns in that small of a room will be even more enjoyable. Chris
  8. Generally, this includes horns without bends in their central axes that have area expansion formulas that are a quadratic function of the distance from the horn's throat, i.e., y = ax2 + bx + c In the special case of the conical horn, the formula is y = ax2. This is not the equation of the straight-sided portion of the K-402 horn--it's not conical...but it is straight-sided. Chris
  9. I might agree with you on this point, but look closely at the vertical axes units: the acoustic resistance at the throat of the horn is not normalized to anything but throat area and rho-c
  10. For Sale Jubilee Clones, Toronto area

    You know what Roy says..."the smaller the room, the larger the horns you need...". This isn't a joke, and there are some very valid reasons for it. As far as your HT room, your Belle will be able to provide speech intelligibility for movie dialogue. If you get to that point of discussing how to make the Belle sound exactly like the Jubilees in terms of its timbre, look me up. I can help in that subject area. Chris
  11. For Sale Jubilee Clones, Toronto area

    It's straight...and 39.5 inches wide.
  12. For Sale Jubilee Clones, Toronto area

    Another picture that might help:
  13. For Sale Jubilee Clones, Toronto area

    Here is a build plan view of the Jubilee bass bin, which is probably close to what Tom used: I'd recommend laying out the Jubilee bass bin cross section using the same scale as your room and screen (plan view) and move it around to see if you can find a happy medium. I have used MS Excel and PowerPoint in the past, but paper works just as well. Here is another copy of Bill Waslo's pdf article entitled "Setup of Controlled-Directivity Waveguide Speakers", Oct. 2012 on this forum: Setup of WG Speakers.pdf Chris
  14. For Sale Jubilee Clones, Toronto area

    Too bad...
  15. For Sale Jubilee Clones, Toronto area

    About 5-7 inches-depending on the toe-in angle you choose. Jubs are not nearly as sensitive to being toed-in more than 45 degrees as are Khorns--which must have false corners to do it. The K-402s are good out to 45 degrees off their horn's central axis without any real decrease in SPL--so you can toe-in farther without any change in SQ, and actually stabilize the stereo image better. Good thing you're not using a flat screen TV. Your projector can slightly reduce its image size, too. Chris