Chris A

This looks like a 1.4" Geddes-type throat (oblate spheroid, or "OB") with a straight-sided square-mouth horn completing the expansion. I bet it would sound good. But note that Geddes has trouble with his OB horns if trying to listen to them directly on-axis-due to the OB throats. I guess the bottom line is that you get less higher-order modes (HOMs) which would permit the horn to sound smoother at higher frequencies, but you really can't point the horn directly at you, so the frequencies above ~10 kHz will be rolled off a little when listening off-axis (which is a function of the 1.4" throat that begins to lose polar coverage at higher frequencies). You'll probably not hear this, however. The lack of a secondary flare as the horn expands toward the mouth will also tend to produce a waistbanding effect on the polars at somewhere between 500-1000 Hz. This is also very difficult to hear unless moving around the room and listening from off-axis angles. There will be a little effect on the timbre in-room because of this, but it's probably minimal. Chris

I'm similarly worried. As the Q&A went on, the last attorney (head of the ACLU?) was being grilled, and several of the justices seemed pretty "spring loaded" in their expectations to their hypothetical questions (at least to my legally untrained ears)--and they tended to keep cutting him off when he started to defend his answers to their, well, not very fair questions. I think the Third Circuit court basically got the decision right in a reasoned and workable way--at least from what I heard. Why would the SCOTUS mess with that ruling? It seemed pretty well thought out and workable. What surprised me was the questioning from the specific justices--the conservative justices all seemed to ask questions that, to me, obfuscated or distorted the issues. But then Kagan and Sotomayer also seemed to join in on the same type of questions, clearly trying to unbalance the decision of the Third Circuit court--not to simply understand--like they had already made up their minds on the answers. Some of the justices seemed to listen more carefully to the answers (Gorsuch & Kavanaugh, for instance, IIRC). I assume that these were preliminary Q&As. (I'm not familiar with exactly how the SCOTUS works from a procedural viewpoint.) So I'm still hoping that reason will prevail, and the students' First Amendment rights become the standard for out-of-school issues. (It's the only interpretation that seems to make much sense to me.) Trying to extend Tinker to the entirety of the student's lives seems like an unreasonable power grab to me--in order to solve issues that Congress hasn't yet passed laws to control. I think that a lot more kids are going to be "shut down" or even quitting public school if the school administrations are armed with more power over the kids lives in order to "assure order". If it's that bad, then why doesn't Congress take up the matter? It's their bailiwick. Chris

It’s pretty interesting to see how confident you are in something that you really have no knowledge of..... How about being a little more specific, Roy, since you quoted a fairly large block of text? What is it, specifically, that you take issue with--my opinions? So let's take my statements, one by one, that you quoted above and address them one-at-a-time: So you're implying now that the current two-way professional version of the Jubilee with the KPT-KHJ-LF bass bins is not "going away" and that the price isn't going to leap from perhaps $10K with Xilica XP and good drivers (replacing the K-691s), to $35K (all USD)? That's part of me "having no knowledge of"? I do know that paying $20K for a current pair of professional (cinema version) two-way Jubilees that someone might have in stock as leftovers is not something that I'd recommend, since no additional value has been provided...as when they were at half that price (for over 10 years). That certainly looks like price gouging to me, but I would guess that's not your opinion. It is my opinion on the subject of price increases without added support or explanation anything other than the phrase "these are the last two new Jubilees that are for sale" (so he's trying to increase the price for them based on that alone). That's 2x price over what appears to be a reasonable price based on historical information. Do you disagree with my opinion on this particular point? I would guess you do, based on the place of your current employment. That's perhaps your opinion vs. mine, however. As far as the use of a separate set of subwoofers + bass bins to lower the AM distortion of the setup, this is physics (i.e., facts), which I don't really argue. If you're saying that breaking up the passband of the bass bin with additional subwoofers does not limit the AM distortion of the bass bin at higher frequencies, then I can say that I'm pretty confident I'll stick to what I said. So you take issue with my assessment that the performance increase of the new vented-in-horn bass bins will offset an already stated $25K price increase from your marketing/sales guys (with upper management approval)--that most people here that look at that will not option to buy a pair at that "new and better (for Klipsch) price". You're on for a Tex-Mex dinner in Hope, AR at a mutually agreeable time and place of your (or my) choosing, whomever wins the bet of "more than 10 present Jubilee owners make the switch to the new yet-to-be-released version of the Jubilee within 2 years, you win and I owe you a Tex-Mex dinner in Hope (assuming it can be had). Otherwise, I win and you owe me a Tex-Mex dinner." Don't worry--I can't eat a lot of food like the last time we saw each other 12 years ago, so my dinner will be a cheap bet. So you're saying that, for me, that the price differential doesn't put the new Jubilee version out of consideration? I win that bet. So you're saying that, for me, the MEH version (with my selection of drivers and DSP crossover support) in a 5.2 array in my living room isn't going to be a match for two of your $35K new Jubilees? I win again, since I can't fit 5 surround Jubilees into my listening room. Is there something that I missed, above, that you were implying in your comment? Chris

See https://www.c-span.org/video/?510036-1/mahanoy-area-schools-district-v-bl-oral-argument All Justices seem to have problems with the degree of punishment in this particular case (implying to me that they believe that the school administration was out of bounds in this particular case in the degree of punishment...and that it took a court case to rectify the situation--which the student won), AND the problem of the complexity of applying both Tinker and other First Amendment restrictions. It sure sounds like the Court is going to modify some uses of Tinker unless there is a clearer standard or standards to apply. Chris

Sadly, in terms of consumer loudspeaker pricing, Klipsch isn't the same company as PWK's company, IMO. The ancillary functions of the company (those departments other than production, buying/materials, and engineering) that don't add value directly to the product are probably a much bigger piece of the internal costs pie chart than they were 30-40 years ago. YMMV. Chris

The miniDSP 2x4 has documented gain problems. I don't recommend it. Instead, the "2x4 HD" at $205 is a very good and usable product--if your high frequency driver sensitivity isn't too high. If you do have a very sensitive compression driver, then I recommend Xilica XP series.

The Xilicas are quieter than the miniDSP "HD" series crossovers. This also enhances the perception of fidelity. The Xilica XP crossovers are about $400-$600 USD more expensive (depending on the number of input/output channels), but note that this isn't a place to "get cheap" as so many people seem to do--with poor results. In fact, I'd get a lot cheaper on the amplifiers used than on the DSP crossover--from my own experiences with both. I can barely hear the difference between a First Watt F3 amplifier and a used Crown D-75A rack amplifier--and the price differential is much greater (used). As a rule of thumb, I recommend the Xilica XP series if your loudspeaker's sensitivity is like a current Jubilee's (i.e., 110 dB/2.83 volts in the high frequency channel). If you're using below 100 dB/2.83 v sensitivity high frequency drivers, then the miniDSP 2x4 HD (and its bigger brother--the 4x10 HD) works well. For instance, I can't hear any noise using ESS AMT-1s with the miniDSP on top of the Belle bass bins. The miniDSP isn't really more "user friendly" in my estimation and certainly it's not worth making a decision buying them over the Xilicas, since the Xilicas have lower noise, as discussed. In fact, I got used to the XConsole application and USB connection within a minute or two of using one. It's much easier than using something like REW (getting the hardware plugged in right and microphone channel/preamp gain calibrated, settings set right, and microphone placed correctly with sufficient absorption on the floor). I recommend the Xilica, then. You'll probably hear the noise floor of the miniDSP from your listening position if using a miniDSP. Don't get cheap at this part--because you'll eventually end up dissatisfied, IMHO. Chris

I expect that the "Tinker test" might be further amplified and perhaps strengthened (or changed) in the upcoming case. From personal perspective, it's still clear that school administrations are still pushing back hard on that legal test or even unbalancing the test since school administrations still seem to make a high number of decisions limiting student freedoms, especially in light of the last 25 years or so with the advent of smart phones, social media, and blogging--which didn't really exist 25 years ago as a significant factor in public life. We're again having to redefine what that balance now means in light of the effectiveness of these new technologies. The limitations of First Amendment rights (on both ends of the spectrum) seems to be more significant of late. Clearly, this is also an opportunity to address some of the newer SCOTUS justices' perceived "bias against conservatism", perhaps shoring up student freedom of speech against school administration perceptions of what constitutes "disruption". We'll see what comes. It's usually a mixed bag (as viewed from individual point of view)--no one is fully satisfied with the outcome. It's a tradeoff, as are all decisions at that level. For the forum participants that are more narrowly focused on matters of music and audio... Here's one that's a lot easier to watch (and listen to): Chris

Here's a good one to ponder: https://www.washingtonpost.com/politics/courts_law/supreme-court-cheerleader-first-amendment/2021/04/25/9d2ac1e2-9eb7-11eb-b7a8-014b14aeb9e4_story.html "Small leaks sink great ships." ref: First Amendment rights of public school students. If you don't like something that your current employer does, and you say something about it publicly (or even not publicly), it's generally okay for the employer to fire you for that. However, you can also go find another job elsewhere. But how about public school districts? Do kids have a right to go elsewhere without a big financial penalty and burden on their families (who may have 11 other children at home, also going to school)? This is a problem, it seems. School kids are, de facto, denied First Amendment rights to anything they say--because they are public school kids. And they can't just change public schools or public school districts if they disagree. The system as it's currently constituted doesn't allow for that. Perhaps kids who disagree with school districts or are punished for free speech off-campus (i.e., they can't say anything that some school administration says they don't like) should be able to take their educations elsewhere--and the money that sends them to their current school--should be applied to a new school, it seems. Otherwise, the school districts have far too much power over student's freedom of speech (and I've seen some really bone-head decisions by school districts before). Where does this lead? This is an interesting Gordian Knot for the Supreme Court to unravel. Chris

The midrange drivers ("K-55") are pretty robust drivers, so I doubt the diaphragms were blown. Much more likely it's the K-77 tweeter diaphragms. You could talk to Michael Crites for replacement diaphragms. He also can help you with the midrange K-55 diaphragms. It's pretty simple to disassemble and replace these once you remove the drivers from their mounting locations. Michael can also help you with crossover servicing and upgrades. There is another service that I think Klipsch has identified much more recently, located in the northeast--which I'm sure others here will chime in to give you those links or email addresses that is "authorized" (but I wouldn't put too much credence into that recognition, since the parts to replace are pretty easy to source, and there aren't very many parts in total). Chris

I've got some in-room REW measurements taken at 1m with absorption on the floor between the microphone and front baffle. The Cornwalls are 1979 models with replaced tweeters--Crites CT125s (which at about 3-4 dB lower sensitivity than the midrange) which already replaced the K-77 tweeters when I bought the Cornwalls used in ~2008. I also have measurements using an EV Dx38 DSP crossover that simply EQs the Cornwalls to a little flatter SPL response--but no bi-amping or tri-amping. I know this isn't what you've actually requested, but it is available in case you get no other offers. Just PM me with an email address where I can send the REW measurement files (*.mdat). If you want me to extract plots from the measurement files, I'd be willing to do that, too. Chris

So what do you think? The language of the domain is digital signal processing (DSP) and like anything else, it's a different language from what most here are used to seeing. The more serious audiophiles might talk about amplifier specifications/capabilities, classes of amplification and their specific types and levels of distortion as they pertain to the exact (and perceived) types of sound quality produced by the loudspeakers. So deep topics in applicable technologies are not alien to our vocabulary. Deep dives into these subjects on forums such as this one aren't really a rare occurrence. Fast forward to today. The technologies now employed (as described above) are something that 40 years ago only signal processing engineers/geophysicists would talk about. My first direct exposure to digital filtering was in the early 1980s. Now your home hi-fi can easily employ IIR and FIR filtering to correct loudspeaker and upstream electronics nonlinearities, issues that couldn't be corrected in the past, and certainly not to the level possible today, and at a price point that's easily accessible to most all serious "audiophiles". The software tools employed are largely free/shareware, and all the documentation is available online. All it takes is additional learning. Should audiophiles shy away from all of this? Not if better sound quality is desired. Are these type of DSP filters going to become ubiquitous in audiophile circles? Yes, especially once you hear a good implementation of the technologies talked about here. You'll probably never go back after hearing what can occur in your own listening room. Does it take some knowledge of "how to do it". Yes. Can this be done "automatically" by using bought room correction software. In my experience, not so much--at least not presently. Someone with knowledge of how to do it needs to set it up in-room. Some beginning tutorials on what FIR filters actually are (a concept that isn't really that complicated...in my opinion): https://barrgroup.com/embedded-systems/how-to/digital-filters-fir-iir More here for those that have heard of digital signal processing (mathematical) transforms, such as Fast Fourier transform (FFT) and the Hilbert transform: http://www.minidsp.com/images/documents/fir_filter_for_audio_practitioners.pdf Chris

This is likely, in this particular case. I guess all human tendencies drive toward this sort of thing if left on their own. Good businesses tend to become weighted down by inefficiencies and frankly...not working as hard as they once did. Other companies work hard to keep their rates and prices down, and cater to a loyal clientele. I can think of a few examples of this. By and large, those companies are still around, while the former ones--not so much. Chris

That's too bad... I hope he reconsiders. Chris

I have reason to believe that the prices that you're talking about are inflated. I'd be pretty disappointed if that was the current price from our favorite Jubilee dealer. Chris

Essentially, using a DSP crossover with digital input(s) would eliminate the need for DACs. So you'd need something like a player/streamer and/or PC to serve the digital files, some form of digital-to-digital converter to handle the PCM-->S/DIF or AES/EBU transition (or a preamp/processor if using more than two channel stereo, or something like DSD files from SACDs, etc.), and amplifier channels. You can also do it using a PC and a PCIe-->AES/EBU card to eliminate the preamp and digital converter. Not necessarily. The issue is more than likely the unbalanced connections, not the amplifiers themselves. Anything from Nelson Pass seems to do very well with Jubilees. FYI: remember that the price of "Jubilees" is going up from ~$7-8K per pair (without Xilica) to $35K (USD) per pair with DSP crossover. If you're going to wait, then you'd have to take your chances with buying used, and I'm not sure how many of the ~50-75 pairs of home two-way Jubilees are going to be around for sale (since the compression drivers on all of the existing Jubs can be easily upgraded to something like Celestions, etc.). That leaves the bass bin changes, and I'm pretty sure that the new bass bin is not going to be reason enough to sell existing Jubilees, i.e., it's better to use a separate set of subwoofers, anyway, so even if sub-32 Hz performance of the new Jubilee bass bins is real, I don't believe that's going to be a big enough enticement for any existing owner to want to "upgrade". I know that for me, the extreme price differential alone puts them out of consideration. I can easily do a better job myself with DIY K-402-MEHs in a 5.2 array for /10th to 1/5th the price per loudspeaker, depending on the cost of the drivers. YMMV. So the bottom line is...if you want a current two-way home version Jubilee from the professional line, now is the time to buy from the remaining stock (if any still exist). Otherwise, you're going to have to compete for the used Jubilees that come up for sale--very occasionally (like one set every two-three years--or perhaps less often). Even if you had to take out a loan now, it might be better now to avoid that huge price increase that's coming in 2-3 months from the date of this post. Chris

I tend to accept this at face value. My experiences have shown that it's in the most difficult area to correct--the bass (because of the number of taps required)--that the improvement is the most easily heard. It's interesting that the ear apparently wants to hear minimum phase, but the easy way to correct bass phase growth is through increased FIR filtering time delays (i.e., a design tradeoff). One thing that I haven't talked a lot about is the high-pass behavior of the bass bins...that creates most low bass loudspeaker phase growth. The lower the f3, the lower the phase growth (all other things being equal--which they're not...). If you want the sound of really deep bass, then it might be easier to provide a subwoofer with a very low f3 and flat phase response. Here is a discussion on the very low frequency phase and group delay behavior of some bass bins that may be of some interest. This is the reason why I gathered the data and plotted it...to discuss the low frequency phase/group delay behavior of bass bins. I now believe it's pretty important to select something that's got flatter phase response: https://community.klipsch.com/index.php?/topic/182419-subconscious-auditory-effects-of-quasi-linear-phase-loudspeakers/page/8/&tab=comments#comment-2597971 Chris

Well, the crossover frequency from the woofer to the compression driver is 1660 Hz. That means that the second harmonic of the woofer can be as high as 3320 Hz (and as low as 120 Hz), third harmonic as high as 4890 Hz (and as low as 180 Hz), and fourth harmonic as high as 6640 Hz (and as low as 240 Hz), etc. These higher harmonic frequencies are generally above the fundamental frequency of most instruments and voices. The sibilance syllables are in the 4-8 kHz region, so you're probably hearing higher order harmonic distortion of the woofer--higher than third harmonic distortion frequencies. Additionally, modulation distortion will be quite prevalent up to that 1660 Hz, forming side bands around the higher frequencies that play simultaneously (the difference and summed frequencies at the second frequency f2, shown below), thus leading to a thick and opaque sound up to the 1660 point (which happens at the same time the loudspeaker is also producing harmonic distortion): More on this subject here: And a fairly famous paper on that subject of "The Mud Factor" by Paul Klipsch: https://community.klipsch.com/applications/core/interface/file/attachment.php?id=162634 (Note: horn-loaded acoustic drivers simply do not have modulation distortion like direct radiating acoustic drivers---which is something that almost all loudspeaker reviewers miss.) Well, not having boundary gain supporting the R-51M woofers is going to be a fairly big factor, and pushing the R-51Ms back to the rear wall (and re-EQing them to flat response) will delay the point of transition to overwhelming harmonic and modulation distortion by few dB and a few Hz. I'd certainly try putting the R-51Ms into boundary gain, if possible. You can also form an artificial backstop touching the back of the loudspeakers with a "false corner" or a little wall just behind the loudspeaker. Any size of this backstop up to about 56 inches (1/4 wavelength at 60 Hz) would help the sound quality at higher SPL. Chris

Invitation is open--and we're all vaccinated. Chris

I found it (phase flattening and group delay flattening) not so subtle with full-range loudspeaker directivity (down the room's transition frequency) and nearfield control of early reflections. It almost knocked me down when I heard it. The problem is, it's difficult to describe. Chris

See: https://community.klipsch.com/index.php?/topic/182419-subconscious-auditory-effects-of-quasi-linear-phase-loudspeakers/&tab=comments#comment-2366185 Chris

Okay...we can agree to disagree on this point of audibility (both points, in fact)--as a function of frequency. Chris

So you're saying that only group delay is audible--the rate of change of phase...? Chris

I do believe that there is a listening difference between linear phase and flat phase (subjective listening), but my experience isn't something that I'd be willing to lay a hat on. It's another question--and potentially another "agreed requirement", i.e., "How much tilt to the phase curve before it becomes audible?" Chris

So the question is: how flat does the phase need to be? For SPL response, audio system standards quote ±2 dB flatness (without "house curves"--which is another can of worms). My experience is ±90 degrees (per Danley). How about your experience? Chris