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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. Chris A

    Best speaker for my space

    I think that many here have suggested solutions for pieces of the puzzle, but maybe not entire solutions. Perhaps discussion of what the symptoms and pictures say is a better way to start. Then you have some mental picture of what may be occurring acoustically. [Understand that without some measurements or actually hearing the setup in your room, the following comments are somewhat conjectural.] 1) "filling the space" is usually a function of coverage of the loudspeakers with direct sound. The Fortes will cover about 90 degrees well, but your particular placement demands more like 180 degrees (half a circle) coverage to fill the dining area and kitchen, toward the front door. I don't know of any Klipsch speakers that will do that and also provide you good stereo imaging as stereo speakers. (I think the comment in jest, above, about having big Magneplanar panels was really addressing that issue.). 2) One requirement for having a sense of envelopment is reflections coming from the side walls. In your room, you've got at least one side (and Travis has of course asked you for a picture of the right side oft he room looking at the speakers to understand just what kind of wall reflections are coming from that side) that doesn't really have reflections, so you're missing that side wall "spaciousness". 3) Note that the coverage of sound really doesn't go through open passageways and halls--it usually gets significantly attenuated when passing through these areas. With the comments above in mind to form a mental picture of what is happening, some suggestions that might help, but not totally resolve your issues: a) Add more speakers to fill those areas around the dining table and kitchen. b) if you have a wall next to the left side of your speakers presently (part of Travis's comment above), you could turn the layout 90 degrees to the left and cover the length of the room. This would address the requirements on loudspeaker coverage to the capabilities of the Fortes that you already own, perhaps eliminating the need for extra fill speakers, and help with bass response--if you can get the Fortes closer to each room corner. c) Spaciousness is also a function of having plenty of acoustic energy available to you. The Fortes will provide enough overall acoustic energy to fill the room (if turned 90 degrees), but you will probably still enjoy having larger horn mouths to keep the direct vs. reflected energy ratio high, even down into the lower midrange and midbass, and have enough horn-loaded bass to keep bass modulation distortion low. Adding diffusion panels will help, but I believe that the comment about having Jubilees or some larger mouth horns (including Khorns, La Scalas or Belles) would work better and potentially cost less and be less obtrusive visually. Jubilees have a huge soundstage that will fill the entire room. d) Cornwalls have higher levels of modulation distortion than Khorns, La Scalas, Belles or Jubilees (i.e., horn-loaded bass bins). If you've got a place for Khorns in the room (turned 90 degrees from your present layout), I think that would be the most effective single change that you could make. Cornwalls have fairly good bass extension (more than La Scalas and Belles), but not as much as Khorns and Jubilees. They will color the overall sound when playing at anything above about 85-90 dB at your prime listening position (i.e., the Cornwalls actually work extremely well as surrounds). When playing into a room of the size of yours, I think that would not be much if a step up from your current Fortes. That's enough for now...time to take a breath. Chris
  2. Chris A

    Teacher Question about Netiquette

    The students that need the most help always got the best teachers...in my experience. Perhaps they don't tell you that in your particular district. In Texas, all testing measures the bottom of the scale only (extremely heavily weighted to color of skin)--never the top achievement, i.e., Texas Assessment of Academic Skills--TAAS STAAR - State of Texas Assessments of Academic Readiness. The entire school receives a failing grade if one minority student too many fails to meet standard...and that's one student in some skin-color groups. Chris
  3. Chris A

    Teacher Question about Netiquette

    The charts that you posted say a lot already. In my wife's schools, they always handed GATE (gifted and talented) students to teachers that need the bar a little lower. 👎
  4. Chris A

    Teacher Question about Netiquette

    Any input would be anecdotal from me and definitely not expert. By their 13th-14th year of age, adolescents have the cognitive capacity to do most of what adults are capable of doing, but self-regulation and judgment are still developing. This is a pretty critical set of capabilities for student-led learning, one would think. Some examples online: http://www.ascd.org/publications/educational-leadership/mar14/vol71/num06/When-Students-Lead-Their-Learning.aspx. https://www.facinghistory.org/resource-library/teaching-strategies Most of what I find from educational foundations is what I'd call meta-techniques, i.e., "planning to do the planning" to create what you actually want. This is endemic to the discipline it seems (among other disciplines). Most of the techniques that appeal to me would be direct techniques, i.e., changing the "What" into "How" directly, and harvesting any experiential data on how well each method works, and its limitations. This type of information is usually completely absent. I liken this situation to reading a sociology article: when you get to the end, all you know is a bunch of new terminology...and nothing you can use to actually begin to solve your problems. 😴 Chris
  5. Chris A

    Teacher Question about Netiquette

    You might think that graduate engineering students are significantly different in this respect than 8th graders, but my experience has been that getting everyone involved in online discussions or even in a face-to-face classroom environment is basically unobtainium. There are always those that are either intimidated or indifferent--even at the graduate level (incredibly). I often think of the vision of live mice piled up in one corner of a cage while the pet snake is staring at them from the other end as a good analogue. That seems to sum up my experience with individual participation in class exercises--even if there is a big carrot dangling to entice them. Group exercises are always a different story especially when groups have to present and defend their work/ideas (which is also possible to set up online in forum fashion). This always seems to flush out many more active participants without required cajoling by the instructor. The students then take responsibility for teaching--like graduate teaching assistants--and all seem dig-in in some way or another. This can also be encouraged by the instructor in incremental fashion (e.g., weekly) to shake loose the hold outs by rotating lead presentation duties each week of the group's weekly output--with the requisite motivation supplied by their group members to not drag their team grade down. Then the weekly logs of individual forum postings online form the artifacts for metric use. Spread the good (i.e., already vocal) students across the groups. At the end of the semester, grade the individuals, not the groups. (Don't tell them until the end, however.) I call this "let the microphone do the work for you" (a line from The King's Speech), otherwise known as applying social pressure. This has the side benefit of teaching students how to work in groups for performance at the same time--a required skill nowadays, especially when building writing assignments for larger work products. Online on real forums, you see the same thing happening with different cliques spontaneously forming over almost any subject, and "us vs. them" debate usually ensues. This seems to make up the greater portion of any online forum discussions on controversial subjects of any real value. Chris
  6. Chris A

    Teacher Question about Netiquette

    Some ideas that come to mind: 1) Creating the right environment seems to be the real problem. The means that the students are incentivized to join in the subjects chosen, which are neither too polarizing nor dominated by pat answers, i.e., thinking on the subject is required before responding. On this forum (K-forum) the participants come and discuss topics because of their enjoyment of the subject matter, such as audio, how-to Q&A, general banter (which is also the source of misunderstandings and flame wars), and discussion of current news events. The latter type of threads are typically dominated by what you read on Google News, which includes politics and religion. These are always mistakes--especially for grown people that should know better. Like anyone else we learn by example, and getting someone to model the points in your netiquette reference is tricky. You could use a champion that others will follow or will want to compete with. Starting a group of kids from scratch is difficult. 2) Anonymity tends to stimulate unwanted behavior by those scoring high on narcissism and histrionics, etc. It has to be safe place to learn by doing and making mistakes. The number of good contributions within the netiquette guidelines can a metric. Using the forum as a resource for group assignment discussions is also another way to incentivize. But keep them off Instagram and Snapchat if the objective is writing and learning netiquette. Chris
  7. Actually, I haven't had a DH1A to test or to hear. I've heard good things about the driver but I can't say much about it due to my lack of experience.
  8. Chris A

    The Multi-Channel Music Review Thread

    Title: Goldberg Variations Acoustica [Blu-Ray disc, Dolby TrueHD, 96 kHz, 24-bit multichannel 5.1 format, (multiple mixes available on disc)], 2010, The AIX All Star Band Review I'd call this "third stream" mixed with modern jazz. The recordings are, of course, outstanding. The architect/creator/producer of this album is Mark Waldrep of AIX Records. There is no dynamic processing, EQ or reverb added to the musicians' performances. It is what it is--nothing more and nothing less. I'd call it "captivating" and "low key". Pros: I wish all my recordings were like this one. It's the most unaltered audio disc that I own--basically the downmix unaltered. I'll use this one to demo the lifelike sound quality of the setup. 3D video is available to those having that capability in their surround sound setup. Cons: If you don't like jazz combos that use classical music themes as their source, you probably won't be thrilled with this album's composition--a single 52-minute track based on JS Bach's Goldberg Variations for keyboard. But you will probably still be captivated by the sound quality. Equipment and room used for review: Jubilee/TAD TD-4002 fronts, K-402-Multiple Entry Horn center, Cornwall surrounds, two DIY TH-SPUD tapped horn subs. Room: 15.5' x 40' x 9' high, acoustically treated to control early reflections and mid-bass room modes down to 70 Hz (see my setup page) Rating: 4 stars ****
  9. The ring dual diaphragm design makes a lot of sense especially when you consider the need for a phase plug and the need to avoid diaphragm break-up modes at high frequencies. The BMS dual-diaphragm drivers also control any FM distortion (Doppler) that might show up at extremely high SPL due to the large pass band that it covers. Breaking that up into separate parts kills the growth of FMD above the crossover frequency (6.4 kHz). The fact that they can do it with polyester diaphragms also tells a good story from the standpoint of material shape stability of the moving diaphragm which moves as a ring rather as a membrane with higher order modes--like a drum head.
  10. I always use one loudspeaker at a time, i.e., mono, when listening for sound quality differences in loudspeakers, including the case of the K-402-MEH prototype. I learned that lesson from Roy using mono speakers in listening tests in Hope years ago when listening critically for differences in loudspeakers and their setup. Stereo always disguises sound quality issues. This is why an array of five loudspeakers positioned around a listener always seems to sound better--even if using much poorer performing loudspeakers. The K-402-MEH occupies the center position in my array. But I've also listened to it in the corner, both on the floor and elevated to the height of the Jubilee K-402. The comments I made above were based on all those listening positions. The K-402-MEH picks up almost 12 dB of bass response at 40 Hz in a room corner relative to its performance in the elevated center position. The corner loading case was EQed again to match performance as in the center case. All loudspeakers that are moved to a corner position need to be re-EQed to compensate for the pick up in bass response (which thus lowers bass distortion levels in the case of the corner loading). This is well documented in PWK's writings. Chris
  11. To give others an idea of the differences in total phase growth using higher order Linkwitz-Riley filters (48 dB/octave) vs. lower order Bessel (18 dB/octave), here are two SPL and phase plots. First the Linkwitz-Riley 48. Notice the bottom phase curve with respect to the minimum phase curve: and the same thing but using Bessel 18 filters instead: I didn't use lower order than 18 dB/octave due to the already low crossover frequency for the TAD TD-4002s in both cases (450 Hz crossover frequencies in both cases). Chris
  12. Yes, the anechoic (full space) response of the Jub bass bins is pretty narrow above 300 Hz due to the dual horn mouths side-by-side spaced apart 21.25" and using a truncated mouth like a Belle (i.e., not like a La Scala). I'm not sure what the Jub bass bin polar coverage actually is in-room with floor and wall boundaries since I've not hauled them outside to do polar tests to date. Crossing at 300 Hz with a pair of BMS 4592NDs would be interesting to hear. If I can spring for another 4592ND driver in the near future, then I might be able to hear the difference crossing them over at a lower frequency. The 400-450 Hz crossover frequency presently used on Jubs is almost at tuning fork (A440) pitch--which is right in the middle of the midrange band. Not having to put those frequencies through the folded horn of the Jub bass bin would be an advantage in sound quality, one would guess. The K-402-MEH avoids all that and you can hear the difference in the midrange clarity and presence quite clearly. I believe that this is the source of the real advantage of the K-402-MEH over the Jubilee in terms of sound quality. The MEH has good directivity down to just below 100 Hz--just like the Jubilee and Khorn bass bins--before they both lose directivity control in the horizontal axis. The transition to room boundary support at 100-130 Hz or lower is much less audible than using a direct radiating reflex ported woofer box and crossing at 500-800 Hz (like the KPT-942 or a Cornwall). The crossover of drivers within an MEH is seamless--and you can see and hear that seamlessness with Danley Synergies which use large amounts of driver overlap in their MEHs with their fractional order filters. So crossing at a lower frequency point doesn't make a lot of sense in the case of an MEH. It's better to cross where the drivers sound better and have good acoustic power output capability. Chris
  13. The TAD is of course cleaner on impulse plots, but how that translates into differences in listening performance is perhaps not as pronounced: When I put on a really good recording of jazz or other acoustically performed music that wasn't built from multi-tracked recordings, I can just barely hear the differences in the smoothness of the upper harmonics and the definition of the cymbals, etc. It's a pretty small difference though--enough so that I can recommend either the BMS 4592ND or the TADs for highest performance reproduction. Someone with 20-year-old ears (especially women) might hear a little more difference, and particularly classically trained musicians that have spent some time training their ears to hear very small differences in timbre and attacks/releases. Chris
  14. Chris A

    Is it the DACs?

    It was both a PS3 and an older Oppo 980H where I heard the problems converting to LPCM. The problem disappeared when set to bitstream. The worst performance was using the analog outputs (RCA), which brought a host of distortion issues and level-related clipping sensitivity. The AVP that I own (an Onkyo PR-SC886, which was the flagship AVP from Onkyo in the late 2000s) has better DACs and a lot better bit conversion/decoding capabilities than the players, and the digital HDMI bus from the player to the AVP is immune from noise or other level-sensitive distortion issues. Chris
  15. I've made that shift already. The listening sound quality improvement is noticeable by flattening the phase curve (and its resulting group delay). ...but that's a subject for another thread. (Perhaps I'll start one on that subject soon.) Chris