DrWho

Hey jazz... Have you considered an MTM alignment with the bass horn instead? Also, how much depth are you willing to go with? I've been mulling over an 80Hz to 800Hz bass horn for a few years now and there's always something you have to give up if you want it to be a straight horn. The mouth area requirements for 80Hz make it real hard to get good vertical polars at the xover region - especially if crossing over to the K402. You would think you could undersize the mouth if the speaker is placed in a corner, but I haven't found a way to get the wavefront to align well with the room corner without folding the horn. If you don't align the wavefront, then you end up with early reflections from the corner that create large dips in frequency response at the lower frequencies (due to comb-filtering). Going to an MTM alignment makes the mouth appear larger, and I've been experimenting with ways to use the vertical space to the sides of the K402 to augment loading into the room corner. I haven't found a great solution yet, but I'm still working on it. The interesting thing is that all methods to improve polar response cause the design to start looking closer and closer to Danley's synergy horns. I know Chris is really excited about the frequency response he gets out of his K402 with woofers bolted to it, but I'm not sure the K402 is providing much loading at the lower frequencies...it's been a while since I crunched numbers, but I want to say it was less than a 5% reduction in excursion for the same SPL (which isn't a large decrease in FMD). In other words, it's not much different than having normal direct radiators - the only real benefit is polar alignment. All that to say, I think it would make more sense to make a larger version of the K402 to provide the loading to an even lower frequency, and then port the woofers to reduce cone excursion as much as possible. Unfortunately this makes the xover to the subwoofers for 80Hz and below a lot more complicated due to all the phase happening. A larger K402 ain't exactly a walk in the park either... Also, room modes start to dominate as high as 200Hz in some rooms - in which case I argue the location of the acoustic source is more important than polar consistency to the higher frequencies. (Thinking in light of the dual zoned bass array concepts). This has me returning to the MTM approach - but custom tailored to the dimensions of the room. Basically instead of avoiding early reflections at lower frequency, we can use the room as part of the wave guide.... Granted, these are all reasons why absolute perfection isn't possible - which we probably already knew. I think a split bass-horn in an MTM alignment can give very good results, and would be the best method to have the most control over the height of the tweeter. The only tradeoff is a notch in the far off-axis of the vertical polars, which shouldn't be very noticeable....certainly a lot less of an issue than the polar lobing that happens with the Jubilee LF. This approach will require a cabinet that is roughly 4ft deep if you want good loading all the way down to 80Hz...

Agreed - but there are other ways to cancel out that resonance too....

It's part of that Klipsch sound to keep things overly bright.... While you're at it, why not drop the HF altogether? And replace the MF with a full range compression driver and just go 2-way instead? Might need active xovers to pull this off properly though. Maybe if you're lucky you could do a passive shelf filter to compensate for the constant directivity rolloff? I'm also a huge fan of Tannoy - although don't crank it up too loud, or the highs get modulated by the cone movement, which is not a very pleasant sound at all.

Unfortunately my millennial mind discovered Pandora and I listen to the Yes station instead of buying albums.... It was more fun listening at Colter's place anyway. That was a sonic adventure through history and magical lands of music. That said, this revival of an old thread has inspired me to bust out some Yes.

I hate ringing and beaming too....I'd rather pick up a ton of distortion than have to deal with ringing, which has often led me to direct radiating bass in the past. However, you get the low distortion without ringing on the Othorn. I was so impressed that it could hold its own against the EV MTL-4 (which is a quad 18" dual opposed configuration), which is probably one of the least resonant bass cabinets I've ever heard. It definitely needs a touch of EQ to get it all the way there, but it's not hard to dial in at all. I'm surprised you haven't come across the ringing in your research because it always shows up in the measurements. I wonder if sometimes people don't listen as critically and are too overjoyed with the insane output at the bottom octave that they don't notice/care about some of these things? Or maybe it's the issue of room acoustics which are far worse than what you'll get out of an EQ'd cabinet, and so maybe it's not mentioned because it's on par with what the room is already doing anyway? My goal wasn't to scare you away from the Othorn, but to mention that it's not like other tapped horns. It's got some special sauce that makes it exceptional in comparison.

I have an Othorn with the original B&C driver that it was designed for....it's been so long I've forgotten the model number. While the extreme output capabilities of this sub are undoubtedly impressive, it's the low signal level performance that has me intrigued. It doesn't sound like an SPL Monster at normal listening levels....and that's a good thing. I had given up on tapped horns until I saw the measurements of the Othorn - it doesn't have that characteristic ringing that all other tapped horns have. Being gone in the measurements is one thing, but I wanted to see if it was gone in real life too....which it totally was. The tapped horns have always been impressive form a bang for the buck and SPL perspective, but the quality has always left me lacking.....until the Othorn came around. In the upper octaves (like 40Hz to 80Hz or even up to 150Hz), it is comparable (better in my opinion) to the Khorn/Jubilee/Lascala.....but even better is that it adds an extra octave of depth that the big Klipsch designs don't do. It's totally effortless and unexaggerated - when there's bass in the material, then it's there like you've never heard before. And when it's not there, then it struts along all refined like without introducing any sloppiness. I think some movie buffs and a few dubstep fanatics might feel the 10Hz region is a bit lacking, but I'm not willing to give up audible 20Hz to 80Hz performance in exchange for pressurization of my room. Don't get me wrong, I love to jam out to loud music and make my vision blur from insane SPL (which you can get with the Othorn), but chest crushing loud SPL gets old after a while....so I find myself settling back into more sane listening levels. And it's just reality that you can't hear/perceive ultra low frequency information unless it's loud. All that to say, there is some preference involved, but if terms like fidelity and accuracy end up in your decision criteria, then I don't think you can do better than an Othorn. I also don't want to imply the low frequency performance is lacking either....the dance parties I've held in my basement have been insane, and I've only ever had about 800W available on the amplifier side of things.

I was referring to your constant listing of some arbitrary "dynamic range" number as if it had any meaning. The quote to which I referenced had a long list of music with <20dB of "dynamic range" numbers, but the reality is the true dynamic range is much much larger than that. If you want to keep your head in the sand, then by all means keep it there. But you're obsessing over something that isn't important to the actual art of music. The rest of us don't listen to 3 minute averages. We listen to individual instruments popping in and out as melodies and harmonies move around the sonic space, often listening through things to hear deeper inner details that an "average level" doesn't notice. That stuff is happening on timescales of tens of milliseconds (not minutes), and the cool thing is we're able to hear it because our ears are multidimensional across frequency and time. I can still hear the high frequency decay of a flute at 50dB SPL even though there's a huge 90dB low frequency drone coming from the cello section. The average SPL is still 90dB, but we're still hearing the >> 20dB dynamic range of the flute (probably closer to 50dB). What's more obnoxious is that stuff like this even need to be attempted to be described with numbers. Every musician in the world is tune with these effects - and it's the reason they keep playing even though they're drowned out by other sections of the musical group. That's the whole audiophile pursuit....getting every last little bit of nuance from the brilliance of the musicians..... You aren't going to get there if you're focused on 3 minute averages of musical content. Such discussions totally derail the real audiophiles from exploring the truly meaningful aspects of music reproduction. This isn't arrogance on my part - it's experience being shared in a rude way because I'm frustrated by the ignorance of it all. Who gives a flying monkey about the loudness wars? Go listen to music you enjoy and don't condescend on the music you don't understand.

Here is a scenario for anyone to explore....go build a system with only 40dB of dynamic range and listen to your <20dB dynamic range recordings. Then playback on a system with 90dB of dynamic range. You will measure the same <20dB of dynamic range in both scenarios, but if you don't hear a difference, then you probably have a hearing problem. It would be quite unfortunate for an audiophile to have hearing problems, but unfortunately that seems to be the norm.... Conclusion? A track wide average doesn't reveal the dynamic frequency changing aspects of music. Just perhaps there is a more complicated understanding of how the numbers correlate to our hearing, but far be it for an audio industry expert to suggest such a thing. We have internet experts on the forums to confuse us! The problem with audio myths and human perception in the audiophile world is that people are looking for reasons to justify their preferences....and they'll draw on any misunderstanding as long as it involves some kind of numbers. And there may very likely be some partial truths behind the numbers - and that really muddies the waters with guys like Chris that get so hung up on the one variable they think they understand. The reason I presented him with Nightwish all those years ago is because metal is a genre that is supposed to have a steady state drone to it - which raises the average signal (thus decreasing the peak to average ratio). However, the individual instruments popping in and out of that drone are pushing well over 60dB (measured) - but you'd never see that happening with a track wide average. The whole heavy metal genre is built on this principal....detail beneath the mash of noise. There is no other way to sonically express those simultaneous emotions of sadness, anger, love, and beauty at the same time. Arrogantly dismissing a genre of music because it doesn't fit some arrogantly defined mold is frankly disgusting to me, and that's why I get so direct on this subject.

I stopped reading after this point: The transducers in an audio system are by far the limiting factor for performance. Why in the world would we limit the speaker design to something that is compatible with the SET amp? That's like saying...."I like square wheels, so let's design all the roads so that my square wheels give me a smooth ride" I have no problem with square wheels and funny roads, just as I have no problem with SET amps and have even appreciated some of the incredible midrange detail. I just think the thought process for preferring SET is a bit odd. Why not just embrace it for what it is, rather than call on some odd nostalgia philosophy thing?

The dead time has zero effect at low signal levels if you design your modulation properly.

The Rdson specs aren't the limiting factor when it comes to MOSFETs....switching losses typically dominate the heat generation. I just wanted to mention that Class D designs that maximize efficiency 'usually' aren't maximizing the distortion capability of the system. It's a nice benefit that we don't need massive heatsinks, but the real benefit of Class D is that it has incredibly good performance at low signal levels. I think talking about the heat generation distracts from the true benefit of Class D, which sonically speaking, when implemented well, is going to be superior to Class A. I know some engineering friends that would cringe at that, but I think the numbers are defensible. The characteristics of a delta-sigma encoding are far better than a voltage encoding, but you have to be willing to accept a paradigm shift. We can encode signals in voltage, current, and time. Classical audio uses the voltage encoding because it's easy to wrap your head around, but is it the best medium? Why not encode in the current or time domains? Or why not encode across multiple domains? Delta-sigma encodes in the time/voltage domain, which is the easiest encoding to minimize errors in - especially for bandwidth limited signals. Class A is voltage domain only, and all of its distortions are related to the time domain, which require making tradeoffs. You can keep making delta-sigma better until you run out of electrons, and the parasitic effects of real parts can be designed in such a way that they just cancel themselves out entirely....

Oh, I almost forgot. Crown is getting left in the dust these days. Those DriveCore amplifiers are simply not audiophile quality. I don't like them for prosound applications either. You'd be better off going with Behringer or Peavey (two of the lowest end pro audio brands). In a blind ABX you should be able to tell the difference between the Crown and the nCore. You should even be able to pick them out from an adjacent room.

In college we set out to make our own Class D amplifier. We researched all the options on the market at that time and UcD was definitely the best. Those cheap T amps were close to the worst and limited by the power supply quality. We sat down to understand the limitations of the UcD architecture and came up with a design of our own (sitting on the shoulders of giants). A few years later the nCore series was announced, and it implemented all of the same things (and more) that we had identified in college. That's not to say we were doing anything incredible in college, but to say that the improvements of the nCore are quite dramatic and rather straightforward. I've never met Bruno, but based on his writings we see eye to eye on just about everything. I have the utmost respect for his engineering acuity, and yet he still respects the audiophile phenomenon and cranks out crazy stuff. All that to say, the nCore amplifiers are without a doubt the best amps on the market. They're so good that you have to build special measurement equipment to even quantify the improvement. That's just crazy. Or rather, that's just testament to Bruno's quest for perfection. I too am quite interested by the nCore powered products that Klipsch is coming out with. Are they available yet? Anyone heard one yet?

I think one of the enlightening things about the KP600 is the focus on musical energy/bandwidths.... I think it's mentioned in the crossover literature, but I remember reading it many years ago and a ton of things suddenly clicked into focus. Ideally the system is faithful to all input sources, but the reality is that music isn't an equal distribution of energy across all frequencies. I'd love to see (hear?) the fruits of your experiments some day.

Ya, we are in full agreement here. However, that "smaller and smaller" needs to be considered relative to wavelength. Nobody said each element in the array needs to be reproducing the same frequency content. Nor did we say we need more than one element reproducing the highest frequencies. We also don't need to target a plane wave either (I can think of a lot of reasons why we wouldn't want to anyway). When I think of arrays, I think of them as k factor radiators with a very intentional polar shape (that isn't a plane wave). I think the Anya DSP algorithms are taking a similar approach, but if they're not, then I guess I'm off doing my own thing. My only point is that the classic line array design pushes themselves into a corner that they don't need to be in. They're too obsessed with max SPL. The absence of vertical horn flares in the Anya system lets you have any vertical polar shape that you want. I don't need a hundred drivers reproducing 20kHz - that's way too much k factor. Maybe one is enough. But I definitely want a hundred of those same drivers reproducing 200Hz. It's just how the k factor works out, and unfortunately we can't do anything to change the size of our wavelengths. Thankfully inter-driver spacing matters a lot less at 200Hz. Anyways, that's way off on a tangent and it's not possible to discuss some of the nuances without a real system. At the rate my ideas materialize it will be several years, but I'm confident in this vision. There's some low hanging fruit that's been ignored....likely because everyone in the audio industry is so focused on individual boxes performing specific functions - and that's about all I'm going to say on this subject until I roll out the entire package. Proof is in the pudding, but I'm still trying to figure out how to get milk from a rock first.

A buddy of mine and I are working on exactly the same thing....once we can get our schedules aligned. We won't be doing a K402 though - we'll start with something more K510'ish, but with my own horn recipe, a 1" throat and 900Hz xover target. Once we get the recipe figured out, then we'll try to tackle something larger than a K402 with 2" throat and a multiple entry design like what Chris did with his K402's. This would probably end up flown in the sanctuary at my church. The smaller K510 inspired version is for my 15" 2-ways at home. I've also considered going an alternate route like the EAW Anya system - where they do a vertical line array with horizontal only "horns". This solves the vertical center-to-center spacing problem, and is by far the best sounding PA I've ever heard. In a home setting, it would allow one to completely address all vertical reflections and create a true planar wave through the room. Go with identical rear speakers for a surround setup, add some signal processing, and you can completely null all room modes in all seating locations. You can't get there with the single point source'ish type speakers, but it's also a different type of sound.

They make one - it's called a Forte III, Jubilee, Lascala, Heresy, Cornwall, etc.... Three Forte III's across the front would be awesome, and certainly not too high for the display to be above them.

That's a good point, but I think that's blurring the water a bit. That small little horn on the Palladium line couldn't be loading that 4.5" driver much below ~1.5kHz. That last octave and a half (550Hz to 1.5kHz) is being generated by a 4.5" driver. A 12" driver will do that range a lot better than a 4.5" one. A single 12" driver has roughly 95 sq in of effective radiating area. Three 7" drivers will have closer to 85 sq in. The extra bandwidth required of that 12" driver is almost offset by the difference in radiating area. Also, the MF of the Forte III is going to do the range of 650Hz and up a lot better than the Palladium too. Btw, both speakers sound good....I'm just saying I wouldn't be surprised if the Forte III was perceived as sounding better.

Woah....all these years I though the 396 was a 3-way design? When did that change? No wonder Roy kept recommending the 396. Doh! That's a 2" throat on that horn though, right?

When it comes to the Klipsch speakers....the ones with the bigger horns sound better. The whole story of Klipsch is based on the idea of using horns to lower distortion and control polar response. Because physics is physics and the wavelengths of sound are fixed, bigger horns will load over a wider frequency range. The bigger it is, the lower it will go. The Forte III midrange is a lot larger than the P37F. The P37F needs to use all those small drivers to try and cover the bandwidth that the horn isn't covering. The Forte III design doesn't need the 12" driver to go as high. I think one thing a lot of people forget is that heavier cones are required to do better at lower frequencies. So if you don't need to go as high, then the low frequency improves - and the mids are improving because a horn is doing it instead of a direct radiator.

Forte-I had exponential horns. The Forte-II and RF-7-II have tractrix. That shoutiness is inherent to the old exponential designs. The Forte III is a step above tractrix and exponential - which Roy calls modified tractrix. The Forte III midrange also comes with mumps, which is yet another improvement on the modified tractrix. The LF driver design has improved over the years too, so you'll get good bass with less modulation of the mids. I have no doubt that the Forte III should sound much better than a Chorus II. I would love to see a Chorus III version someday. I'd also like to see a 15" 2-way using Roy's mumps, but someone in Indy dropped the ball with "The Fifteens".

Looking back on my Klipsch history, I've realized I most enjoy the speakers made by Roy...I guess that makes Roy my wizard. I have a huge appreciation for PWK and think he's one of the more brilliant engineers of all time, but Roy's stuff sounds better. I really wish he'd pull off the chains and go to town with his magic. Telsa on the other hand doesn't deserve to be in their category. The guy was imaginative, but wrong about soooo many things. He also didn't understand the inner workings of what he's known for either, and I think that's a big differentiator when comparing to guys like PWK, Einstein, Newton, Faraday, Curie, etc...

I like how Roy voices his speakers - he's really really really good at it. They should have him go through the entire product line and revoice everything that he wasn't involved with.

A passive radiator and a port serve the same function. Here's a list of pros and cons to compare the two Passive Radiators are a lot more expensive than ports. Passive Radiators can freely adjust their Q, whereas Q is fixed for ports. You can make the Passive Radiator operate over a wider bandwidth, but doing so results in less output than a narrower bandwidth. The only way to maintain a flat tonal balance is to add EQ in the electronic domain - which is a free lunch if it's available. EQ tricks work with ports too, but the bandwidth of the port is fixed by the rest of the design. The point here is flexibility - the PR is more flexible from an alignment perspective. Max SPL of a Passive Radiator is a function of its total displacement. The Passive Radiator needs more than double the excursion of the active driver to bring about any appreciable increase in output at the lower frequencies. Passive radiator distortion is limited by the linearity of its suspension. The distortion of a port is limited by the linearity of the air rushing through the port (which turns out isn't very linear). At low SPL's the distortion from both is very comparable. At higher SPL's, the passive radiator starts to be more linear. As the SPL increases to near the limit of the suspension, the passive radiator has a lot more distortion than the port. In fact, it sounds horrendous when the passive radiator bottoms out - it's almost like a muffled clack sound. The port just continues to chuff more and more (sounds like wind blowing). The clip behavior of a port sounds better than the clip behavior of a passive radiator - this is important when trying to take advantage of EQ tricks. Ports have resonances in them that can sound like whistles if its not controlled. Passive Radiators don't have this problem. At the end of the day, you get more bang for the buck with a port. In my mind, the biggest advantage to a passive radiator would be when the box is too small to fit a properly sized port - in which case, you need EQ in the system to offset the rolloff from the small cabinet. This often requires putting them in a dual opposed configuration so that there momentum is cancelled out - which is necessary to keep the cabinet from walking around. If cost is no concern, then it's possible to design a passive radiator to sound better than a port - just as long as you don't ever run the system into clipping. In the case of the Chorus II - I converted mine from passive radiators to a port and I can say the port sounds a lot better. I think this is due to the lack of linearity and excursion capability in the stock passive radiator suspension. Or maybe my passives wore out after all these years, who knows. The Forte III has a 12" active driver and 15" passive radiator, which is a much better balance than the old Chorus II configuration. Btw, somewhere someone mentioned placement flexibility. Honestly, a rear port and a rear passive radiator are going to have the same placement restrictions. You should be toe'ing in your speakers anyway, which means you're naturally going to have enough space behind the cabinet, even if one corner is almost against the wall. This is more than enough space for either the port or the passive to "breathe".

Talking to engineer friends....the reason that responsible automotive companies (read not Tesla) are progressing in this manner is because it's a safe development strategy. It's much less about "readying the consumer." Many of these companies are installing cell networks in the cars so they can data mine the sensors. As the data comes in, they simulate how their new designs and algorithms will behave under real scenarios. More data = more refined. There is a lot of speculation from outsiders about the readiness of technology, its safety, etc, etc.... but then there are those operating with the real data. The list of corner cases to be handled continues to grow. Some of this information leaks out into the general public (like the mylar/foil balloons), but most of it stays in the realm of trade secrets. Gotta protect that intellectual property.... I have no doubt it will eventually happen, but it's not going to look the way it's being described here or in the marketing. It'll probably start down that path - lots of people will die - and then eventually the proper infrastructure will get put into place. It's a very straightforward design challenge with the proper infrastructure, but we simply don't have that infrastructure yet - and trying to put all the smarts into the car is the wrong solution. It may be a necessary development step, but I long for a day when we actually come together as a community and decide we want to do something well. All the misinformation and sensationalism does not push us in that direction - and that's really frustrating for me. But even more frustrating is the rogue irresponsible behavior from Tesla to inflate their stock prices.