DrWho

For speaker xover work, you don't need a fancy iron at all...That $20 weller is more than adequate. The thing about soldering irons is the quality of the tips is the largest factor. The more advanced heating mechanisms are really more about convenience 90% of the time. Things take less time to heat up, and you can handle longer dwell times without damaging components, but you don't need that for speaker xovers. Just crank up your iron to the maximum temp and finish your solder joint in under a second. If it takes longer, then fix how you're holding things so they don't pop apart on you. I have a $3k Weller station at work....it even has a touch screen interface with a screensaver (why? I have no idea). I wouldn't trade it for the world, but the reality is this iron is worse than the $20 weller once the tips go bad. The benefit of my iron is that it goes from cold to hot in a few seconds and I can do longer dwell times without damaging my tiny components (tiny as in the size of a grain of sand).

But how do you know it's stiff? Serious question btw. Just to play devil's advocate - there is no shortage of people enjoying the results of all sorts of designs that I would personally consider mediocre. Maybe someone enjoys the distortion from these drivers? Not to imply that there is distortion there - just trying to explain some skepticism. The thing is, the design of most guitar cabs (and I'm including bass in the guitar category) is often going to lend itself towards T/S params that would be good for horns. I had always just avoided the category based on what I was led to believe made a good sounding guitar cab. Assymetric motor assemblies, softer cones, etc... I guess in a horn one could argue that the driver excursion is way reduced to make those issues less problematic?

There is no such thing as a capacitor....once you freed from that paradigm, then the discussion of capacitors becomes a lot more straightforward. The common problem with audiophiles is they read a little bit of math or whatever and latch onto ideas that aren't applicable in every circuit. This article was pretty good in that it added one resistor to the analysis of the circuit. However, a single R and C isn't the whole story. Trying running this kind of analysis with a proper active circuit with several components. The "rules of thumb" don't behave the same way everywhere.....so rather than get hung up on capacitor type, I think we should explore the behavior of topologies and understand the mechanisms by which the sound will be altered. Going to "better parts" just means the magnitude of the alteration is different (sometimes) - but you always have that sonic signature present. I guess I just cringe when I read things like "ceramic caps create audible artifacts when used as supply bypasses" - or "this cap type sucks". There are circuits that sound better when ceramic caps are used - both as bypass or coupling. The capacitor type can't be discussed outside the topology of the circuit it's being used in. I work hard to pick topologies where the component quality doesn't matter - and when it does matter, then we just pick the best part and stop worrying about it. Capacitors are rarely the limiting component in a design - except for this small crap I work on where everything needs to be ten times smaller than the straightforward solution. So much mythology around capacitors but it's actually a straightforward subject. Anyone trying to play the black magic card is simply lacking in analytical skills. All the pertinent info is in the datasheets if you look for it.

Have you used "guitar speakers" in bass horns before? I thought they go with smaller voice coils (larger unsupported diaphragm area) and thinner diaphragms so they can get intentional cone breakup to get that nice distorted guitar cab sound?

How was it this year? I was outta town so I couldn't attend...

Haha, what? Did you not enjoy it last year?

I can't speak for doc but I don't believe he's talking about a single sub set up. Correct. However, I'm not talking about randomly distributing subs throughout the room either. We can name drop all day long, but the performance is what matters at the end of the day. Maybe all those experts need to read up on this simple concept: http://www.nubert.de/downloads/optimierung_der_tieftonwiedergabe.pdf?PHPSESSID=qctxokyy http://www.avsforum.com/forum/155-diy-speakers-subs/837744-double-bass-array-dba-modern-bass-concept.html

In the graphs you posted, the one with four subs in the middle of each wall will sound bad.....the issue is both systems are bad. If we want to talk ideals, then let's not discuss which is the least worst. There are solutions that yield a perfectly flat frequency response in all seats.

My room is my horn.....I don't need to add random caverns to ruin the same result

Kohls isn't any cheaper anyway - you gotta play all their sale / coupon games just to pay the same price as other stores. Not a fan of Kohls.

I very much prefer stereo bass, but the problems with room modes would have me sooner go mono if the modal situation required it. In other words - fix the frequency response first, but if you can add stereo then it's a minor plus. It really depends on the source material. Localization and Directionality are two different concepts. I would also posit that the localization that matters is not related to our classic hearing mechanisms. In other words, localization of bass is different when listening on headphones versus listening to speakers. Most of our sensation to low frequencies happens in our chest cavities. There is also the issue of distortion products that are there even with an infinitely steep xover.

Maybe he was chasing a mouse...

Most horns are harsh Dave....audiophiles in denial like to blame the source material. The Khorn uses harsh/honky horns. Yes, there is source material that is not as affected by the harshness/honkiness, and you happen to enjoy a lot of that source material. However, to make a blanket claim that all source material needs the negative (as in opposite) of the horn coloration encoded onto it is just narrow-minded at best. The K402 is a huge step into a less colored direction. And you know what? A lot more source material that was once unlistenable on the Khorn is suddenly quite enjoyable. My biggest critique of worshiping PWK and his religious "corollaries" is that audiophiles use it for purposes of justification rather than understanding.

Why would I care about that when conducting comparative analysis? Btw, the stuff form Capital Records is not what I'm proposing here.

Speaking in categorical terms does not bring about further understanding of what is being discussed here (or with any subject for that matter), nor does using buzz words indicate an intricate understanding of the subject. People go about analyzing all sorts of stuff - like applying mathematics to Bach, or defining "best practices", etc... The people actually engaging in the creation process aren't following guidelines derived from others analyzing what they do. Talking about these things in these categorical ways totally misses what the creative people are actually doing. And if that is to be the extent of the conversation, then there is very little to be gained by having it. Kansei is not the reason that technical driven approaches are bad design philosophy. It's because nobody wants technical performance only. Nobody wants to commute to work in a Formula 1 car - no matter how hardcore of an automotive purist they are. It's also a bad business strategy too. I think it very rare that a good design isn't marketable - almost by definition actually. Kansei is just a red herring concept that I've no interest in discussing.

As far as double-blind tests.....double-blind is not required by someone without bias. Instantaneous volume matched comparisons are what's more important - but you aren't gonna get there with big massive machines moving stuff around. The best way to compare speakers would be to actually record their output in an idea acoustic space - and then playback through a good in-ear system where you can compare against the original source material too. The double benefit here is we can make those recordings available for analysis in our own homes. I'm surprised Klipsch hasn't attempted something like this for their speaker lineup - they even have a great anechoic chamber with a true 1/8 space corner to do this in. Shure has been doing this with our microphones for a while now: http://www.shure.com/americas/support/tools/mic-listening-lab

I certainly don't subscribe to Kansei, but all you need to do is go to a big audiophile show to see how much the visual and tactile aspects dominate people's perceptions.

Good product design is so much more than the technical merits of an approach. The original iPhone is testament to that philosophy - from a technical perspective it failed in every way when compared against the Blackberry phones of that era. Where is Blackberry today? The hard reality of the audio industry is that people don't want the result of pure technical capability - and I'm especially talking about the highest end professionals and musicians. There is so much more to good audio design, and there are mountains of data showing how much the non-technical aspects of a design matter to the perception of quality. The purist approach simply is not the best approach from a holistic perspective. Focusing on what people actually want is so much more than a business argument. The technical aspects of a design are merely tools for accomplishing those holistic goals. This is why I'm such a strong advocate for quality knobs....that oldschool analog feel for our modern digital gear.

Something I read earlier over at James B. Lansing forum. Which brought up another question. If drivers and phase plugs are designed to work with certain horns. How could one tell if a driver of one brand is going to work with a horn of another. Could it be that even engineering specs on paper couldn't answer this, but mainly trial and error? That is why I was looking at the JBL 2446, however looking at the specs there seems to be a nice drop around 9000 hz. http://www.fullcompass.com/common/files/7948-2446.pdf But would installing the BE change any of that, or just make it easier to eq the higher frequencies? You need to look at the plane wave measurement - not the frequency response of this driver mounted on the 2380A horn. The only significant aberration I'm seeing is a big dip at ~12kHz. It's not clear to me if it's a cone breakup issue, or a phase plug issue - both can create a response anomaly like that. Unfortunately the impedance response is overly smoothed to not provide any clues as to the behavior - but even that isn't always conclusive. Also, a 2" plane-wave tube is too large to support true plane waves above 6.8kHz. So the combination of side-wall reflections in the tube, diaphragm flexing, and phase plug limitations can all be factors in that specific measurement environment. I think the dip at 12kHz is real, but some of that smaller sharper jaggedness can just be the measurement method. All that to say, going to a stiffer diaphragm may smooth out the ripples that start happening above 7kHz, but I wouldn't hold my breath. I have read that part of the phase plug equation is keeping the pressure low enough to not overcome the diaphragm stiffness. The modifications to the phase plug to achieve that goal can lead to the phase plug itself causing ripples (due to phase cancellation of the multiple path-lengths, and lowering the resonant frequencies of the chambers). Going to a stiffer diaphragm would allow for a different phase plug design, but you're not changing the phase plug here. Another thought to throw out there (since we're talking about diaphragm materials). No matter what, the diaphragms are going to flex - and we have source material that will have larger amplitudes followed by short amplitudes (the natural dynamics of music). To some extent, the sound that we hear is very akin to striking the diaphragm like a cymbal - which will ring and have its own characteristic sound. Actually striking the diaphragm is a bit exaggerated since we don't have that kind of impulse generated by our source material, but I think it's helpful to think that way when comparing the diaphragm types. It's much like using an impulse response to characterize the acoustics of a large hall. Anyways, one of the reasons I like the BMS drivers is because they use Polyester diaphragms. It's nowhere the stiffness of Beryllium or even Aluminum, but it's intrinsically a much more damped material. Striking it like a cymbal almost makes no sound whatsoever. The stiffer Berrylium drivers ring a ton more - they just push it up higher in frequency. BMS is also taking advantage of the annular ring geometry to provide the stiffness they need. I wouldn't use these kinds of diaphragms for huge SPL environments, but for home listening I think it's a much more natural sounding diaphragm - and it matches closer to the distortion characteristic of the paper diaphragms we're using on the woofer sections. It basically allows for an easier to voice system. Ya, it might measure slightly higher distortion and the annular ring has to move further than a standard diaphragm since it inherently has less radiating surface area - and its radiating surface area modulates with excursion.....but all of those things matter less as the SPL gets lower and lower. The stiffness of the diaphragm is an issue at all SPLs - in other words, the diaphragm bending is proportional to the driving force - less SPL, less bending, but the bending proportion to the SPL stays constant so the distortion doesn't necessarily improve at lower SPL. This is way over-simplifying the topic and I bet the compression driver designers out there would probably cringe reading this, but it's the best I can understand it based on what I've read thus far...The simple observation I'm making is that BMS can achieve similar performance with a much softer material because they're using geometry to their advantage. One consequence is that they can use a more natural sounding material. The diaphragms simply can't ring because the material is over-damped. I personally don't listen anywhere near the levels of the rest of you crazies, but I personally would take the BMS over the TAD all day long. The fact that it's cheaper is totally irrelevant - although still certainly a plus. I wanna see BMS come out with a dual annular ring that fires from both sides - basically a free 6dB less distortion. The only point I wanted to make was to consider the inherent characteristic sound of the various diaphragms as "measured" by its "cymbal-like" properties. Somewhere there is a CSD plot showing less in-band ringing from a Mylar diaphragm when compared against Titanium, Aluminum, and Beryllium. Having a Beryllium description doesn't automatically mean it's a better driver - it's gotta be designed with the specific system goals in mind. Most of the guys pushing for Beryllium are doing the crazy high SPL stuff. JBL almost openly admits their Vertec system is only about SPL...they're making tons of distortion compromises along the way to get there. They're the biggest user of Beryllium diaphragms that I know of... And how come we don't see any Berylium direct radiators?

From a system perspective, they both matter...and one might even argue that the phase plug and diaphragm are designed together. That said, I'm not sure I've seen any data comparing phase plugs between any compression drivers out there. I think that's probably because the diaphragms have the largest impact on the flavor of the sound. I also don't tend to listen at 140dB SPL either....and I SPL match my distortion / wavelet comparisons.

The tenants behind PWK's design philosophies have very little to do with good business strategy. If you want to see a good business approach that offers quality sound, then look at what Bose has been doing all these years. The problem with horns is that a bad horn sounds much worse than a comparable direct radiating solution - and I would posit that a small horn falls into the bad horn category. The market wants small, and that is what necessitates raising the HF corner of the direct radiating solution. We've been seeing Klipsch do for the past couple decades. Heck, even PWK made that concession with the Heresy so it's really not a new concept.

What's interesting to me here is how defensive people are for a person who clearly didn't keep up his end of the bargain, and should we really take it at face value that these people "didn't know" they had a loan? Was there signature not on the paperwork? Arresting might be a bit extreme, but I bet you papers were served first and simply discarded. How much junkmail do we get these days? What's worse is all the predatory student loans given out to students getting degrees in meaningless fields. That's really a crap gamble on the bank's part, but remove the risk and then they don't care. Ironically, the government removed the risk because they wanted more people going to college....so definitely don't entirely blame the banks here. Blame the general public for believing and teaching the stupid notion that everyone must have a college degree....oh wait, but it's not popular to blame ourselves for our own stupidity Perhaps that's why we want to defend the idiots that "forgot" about their loans? -said with a smile of course

Maybe Dave will share the video of him kickstarting the frog so we can all perform the surgery on each other...

Hah, no PHD here.....just obsessed with the British Sci-Fi show. I picked up the nickname like 20 years ago and it stuck. And there's no way I'm gonna touch Hawking's math skills - the dude is crazy brilliant. Actually, I had to look up some of the terms used in the second article Don posted. That high level stuff really requires one to speak a different language. Hawking's math is good - that's never a criticism I have of theoretical scientists because that's the entire foundation of their principals. Really really good math and lots of really really good logic. So how could I criticize his conclusions if I think good logic was employed all the way through? The answer to that is at the root of the observation I'm trying to share. And it's in that area of weakness where I feel the other great scientists of the past have excelled.

I was a physics major and finished all my physics courses before swapping over to electrical engineering. I've taken special relativity, quantum mechanics, thermodynamics, particle physics, nuclear physics, semiconductor physics (similar to quantum), and optics. My dad used to work at Fermilab so I've spent a ton of time over there talking to the scientists and some of my profs worked there too. We've had some fun discussions about the parallels between audio measurements and light measurements (both involve waves). The tradeoff in time-arrival accuracy versus frequency accuracy that you must choose when making waterfall plots of your room acoustics is a great parallel to the Heisenberg uncertainty principal. That observation has had the largest impact in my understanding of the "information" and "probability" ideas that come out of the math, and is how I'm able to reconcile the idea of causality - which is one of the foundational tenants to the field of science.