DrWho

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About DrWho

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  1. 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.
  2. 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.
  3. 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.
  4. 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.
  5. 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?
  6. 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.
  7. 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".
  8. 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...
  9. 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.
  10. 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".
  11. 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.
  12. Btw, here are some STC for Plexiglas: http://www.eplastics.com/Plastic/plastics_library/Plexiglass-Noise-Reduction But note the caveat below the charts: For free-standing plexi, you can subtract a good 10 to 20dB from these charts. 4" may have been an exaggeration, but the point is you can't get it thick enough to pull off numbers equivalent to a good cardoid without other implications.
  13. The PZM pattern is the same as an omni-directional with the bottom half cut off - just a single hemisphere. In fact, the construction of a PZM is really just an omni-directional capsule placed as close to the boundary as possible. This means comb-filtering above the 1/4 wavelength distance - and that's where the special sauce happens. Your rejection pattern (the side opposite the hemisphere) is limited by the attenuation properties of your boundary. A thin piece of plexi doesn't offer consistent attenuation and gets less as you go lower in frequency. And diffraction is the reason the panel needs to be large - again, something that gets worse as you go lower in frequency. Guess what - polar control of the speaker gets worse as you go lower in frequency too. And cardoid mics don't sound awful. When are you going to start recommending magic microphone cables and special power cords?
  14. The polar pattern tells you the relative pickup of the microphone in different directions. Directly in front is normalized to 0dB. As you rotate around the polar pattern, the sound pressure turned into voltage decreases as the polar bubble moves towards the center. The steps in these charts are generally 5dB. When you place a microphone in a system, the GBF benefit of the microphone is the on-axis response subtracted from the off-axis response. The on-axis response is defined by the angle of the mic relative to the desired source (the person talking). The off-axis response is defined by the angle of the mic relative to the undesired source (the speakers or reflection points in the room). If you want to be hardcore, then you need to sum the energy from all of the undesired sources. We don't need to run real numbers though - just point the rejection lobe of the microphone towards the source of feedback. Here are pictures illustrating the concept. The PZM on-axis and off-axis response is the same - so the GBF benefit is 0. With a cardoid, you could be as high as 20dB, but in practice it's usually more like 12dB (because there is usually more than one feedback path). Using plexiglas, there is a lot of complex frequency dependent behavior happening - even if you position the PZM so that the 180 degree pickup is pointed away from the speaker. It's because the plexiglas isn't infinitely large. The plexiglas also lets sound travel through it, as well as vibrates at certain frequencies (it becomes it's own reradiator). At the end of the day, the cardoid is already providing a 180 degree pickup in the forward lobe, and provides better attenuation in the rearward lobe. Now if you wanted to use some 4" thick plexi in a 4x4 ft sheet, then maybe you'd get enough blocking - but why stop there? Why not put everyone inside a fishbowl?
  15. Hah! Nice!