DrWho

0dBspl?!? Talk about a really really cold room!

For what it's worth, I actually saw the patterns quite readily. The reason for my comments is because I've realized that I need to practice submitting to "conventional thinking" in order to be a successful engineer. Math just works - there's a reason it exists. Anyone can find patterns. Not everyone can determine causality. Understanding the causality is where I think the genius resides because that's how one then controls the mechanism and actually does something with it. I do find it interesting though that you immediately went to a different notation to describe redefining the function indicated by the + symbol. However, if you're going to redefine the + symbol to mean another function, then why are you using the + symbol to denote the 'new meaning' and 'classic addition' at the same time? Yes, I understand colloquially what you're trying to communicate, but it's still not logically presented. Using substitution, your function requires that fn(a,b) = fn(ab,a). The solution space for that function definition does not include the numbers presented in the riddle: fn(1,4) = 1x4 + 1 = 5. fn(1x4,1) = 1x4x1 + 1x4 = 8. If you want to redefine the + symbol to denote a function that satisfies the number set of the riddle, then you must also create a new symbol to denote classic addition. Yes, I'm totally being obtuse, but it's with the intent of denoting the beauty of the math as the language of logic. Why not just present the riddle as follows: fn(1,4) = 5 fn(2,5) = 12 fn(3,6) = 21 fn(8,11) = ? This way we don't have to play games with semantics, and we can honor the beauty of math in the process. We can then also apply linear algebra to this given set to derive the possible outcomes for the question. If we allow for any dimensionalality in the function, then there is a going to be a confined infinite number of answers. The fn(a,b) = ab+b is not the only solution space. We could have any of the 3rd order and above polynomial expressions, or we could implement a recursive function. A true genius would derive the form for the entire solution set. That is what the field of linear algebra explores. I think the solution set in this case might actually be unconfined infinite, so why not throw in any result for fn(8,11)? I bet we can find a polynomial that satisfies all numbers between 0 and infinity. But if that's true, then is it really a riddle? Certainly not a good one! Btw, this result is still true if you want to accept redefining the + symbol to be an arbitrary function....and that's my point, it's a totally ignorant riddle in that regard. And that's why an answer of 19 makes way more sense....and the riddle is that two of the statements are false, which would even fall into your cryptography argument. Obfuscation is a very good tool for hiding meaning.

Because we're geniuses

I'm not sure I'm tracking with you Jeff. Just think through the mathematical grammar of the riddle.... It starts with 1 + 4 = 5. Okay, that's easy for everyone to understand. The next line starts with 2 + 5 = 12. Okay, normally we expect 7 in a Base 10 system. The riddle doesn't have 7 as the result, so now the logical process is to reevaluate our assumptions. Perhaps it's not a Base 10 system? A quick check reveals that a Base 6 system gets the closest, but 2 + 5 = 11 in Base 6, not 12. Okay, so maybe the numerical symbols have different weighting? At this point I would pause and point out that this is really digging deep into "assumptions" and there isn't much value in changing the weighting of numerical symbols. However, it is a riddle and we must at least assume proper grammar, right? Isn't grammar usually at the foundation of most riddles? Unfortunately the symbol for 2 exists in both sides of the equation, which poses certain limitations on how addition works. To end up with the same least significant digit, you must add by an integer count of the Base....Base 5 doesn't have a digit for 5 (five is represented by 10 in base 5). If you understand how to count, then this should be an aha moment at the absurdity of what was written. I could expand on more problems with the riddle (I actually analyzed several others before seeing the fundamental counting problem), but I don't think it's valuable to delve deeper because the problem statement itself is clearly broken. I used spelling as a visual example, but this is really deeper than spelling. It's striking at the very fundamentals of math. I get on a bit of a soap box when it comes to math because these simple fundamentals are actually wrought with incredibly deep truths....and our educational system totally misses it - at all levels of education. I also have a huge vendetta against this "infotainment" crap that propagates social media. It's not that I'm against information being entertaining, but it should never be at the expense of truth. The laziness that goes into these little quips really erodes away at the knowledge of our culture - but it often goes by ignored because of the satisfaction we feel for "seeing it". I'm not just talking math riddles, but all the other reductionist simplification of incredibly complex interactions. My Facebook wall is full of "friends" posting these prideful, yet ignorant remedies. Back to this riddle, you only "see it" when you don't submit to a proper understanding of counting and addition....and yes, it's really that bloody fundamental. The crazy thing is it wasn't until well after college that I realized I hadn't learned how to count properly. Not that I couldn't count, but I didn't fundamentally understand it to the level I do now....and it's that new understanding that makes this riddle incredibly annoying. I think we way underemphasize the wisdom of the ancients that were exploring the depths of mathematics. In other words, I agree with Quiet Hollow who said it in much fewer words

Your notation in the way you presented your 2,4,6 pattern is very different. You might see it as being anal retentive, but it's the sloppiness in notation that causes so many problems for people trying to learn math. It's not wisdam to interchonge o's and a's even thaugh it's understondoble to a humon. See how awkward that looks? To a "genius" that's how the riddle looks....except it looks so awkward it implies a completely different meaning.

There are fundamental principals in math that force this to be an invalid number set. Finding a pattern within a partial set does not make that pattern logical. That's called confirmation bias, and is a form of illogical thinking. Math is the language of logic and "riddles" like this violate such basic (yet profound) ideas that have me concluding "arrogant ignorance" as my final answer. Btw, I'd love to be shown wrong. I went through and analyzed this giving the numbers arbitrary weighting and assuming an arbitrary base system but it still is invalid. If you want your fancy patterns to be the answer, then you need to modify the notation of the riddle statement.

Dang, I have huge respect for the guys in cars like that that are able to get up tight on the cones in autocross. What's the steering rack like on your car? I bet it's a fury of flailing hands to get through the slaloms. There was one autocross where a ploom of smoke billowed out from behind my car and I thought I had totally roasted my clutch - I was pushing through a slow corner so I dumped the clutch to throw the rear end around the hairpin and the engine just slammed into the revline and there was no motion on the car. Thankfully it turned out all that smoke was the inside tire spinning up to 40mph while I was going about 10mph....the plight of having an open-differential (and not setting the car properly going into the corner). So how'd you get your car home after blowing a head gasket? That's always my biggest fear at these events - especially when they're far away from home.

Well it was No-Shave November!

I felt like I learned a lot more with all the head butting too. The conversations just die off now and we rarely get into the complexity anymore. Maybe part of that is we've grown tired of debating the same subjects over and over so we're less keen on getting into it? We gotta get some of you tube guys up to speed on Class D topologies. A buddy of mine was working at Fermilab and was explaining why they use tubes in their particle accelerators. The advantages in the Fermilab application directly apply to one of the dominant distortion mechanisms in Class D designs. Btw, I'd agree that the sound quality capability with live music has dramatically improved. That (not so new anymore) Anya system from EAW sounds amazing.

I think I could fit a Promedia system in the trunk. Does that count?

I started off with an FR-S, but right now I'm driving a Lotus Elise, number 196 with the Windy City Miata Club. Insurance rates have been completely unaffected. It's technically a gray area with autocross and insurance companies are using stricter verbiage in the contracts, but the short story is that you'd have a hard time breaking your car during an autocross event. There is separate racing insurance if you really want coverage while racing, which is recommended for track days. I've never purchased racing insurance and use that as extra motivation to keep myself focused on staying in control. The racing books I've been reading talk about how you can learn to drive fast without ever spinning out or crashing, so I'm working real hard on honing those techniques. You're well beyond the fast line by the time you're flying off the track, and there's a lot of margin inbetween. Here's a picture from my last event where I placed second, 0.6 seconds behind an Exige. The Exige was race prepped with another 100hp, racing slicks, and racing suspension. I was running on stock suspension with all season tires It was by far my best driving yet. Racing slicks alone would have been good for another 1 to 3 seconds on the track that day, but I've been holding off on vehicle upgrades until I've fully upgraded the driver. My car was good for another 0.5 second if I could have put everything together in a single lap. Daily driving, even in the winter....

Out of a lascala???? No way. Don't get me wrong...some fundamentals will be reproduced, but they're at a much reduced level compared to the rest of the spectrum. Even when in the corner. Actually, a lascala tucked into the corner gets a nasty 1/4 wavelength boundary notch due to the shape of the cabinet. I guess most people have brutal room modes to contend with so it's probably not as noticeable until you're in a room without those issues. The lascala/belle speakers "need" a subwoofer for many genres of music, and especially movies. It can't be a mediocre sub because that ends up being super distracting from the quality of the rest of the system.

I do a lot of autocross and have done a few track days....including tackling Nurburgring over in Germany. Getting ride-alongs with excellent drivers is a much more amazing experience though. Even when I know a track and can drive just as fast myself it's still scary awesome. While riding you don't have that anticipation of when the driver is going to brake and turn in, so you're constantly feeling like you're going to fly off the track while getting whipped around in your seat. The good drivers also make it very apparent when you can get more out of your car, which is super helpful for improving your own skills. I just wish racing wasn't so expensive. I focus on autocross because I think it's more telling of the driver, but it's also a lot cheaper. There are a good number of guys in my club that will take their commuter car to autocross events. I think people are normally embarrassed to show up with a boring car, but it's highly encouraged by the more hardcore guys. It's the perfect place to learn the limits of your vehicle before you're in a real emergency situation on the road. Nevermind the fact that it's a lot of bragging rights to beat out guys with fancier cars What track were you guys at, or was it a parking lot event?

Soooooo true. I use batteries all the time for testing because they're soooooo crazy quiet and really the best source of something that looks like DC.

Leakage current in the X-Y caps......it's always there regardless of power supply quality. Batteries are totally the way to go.....

I've become a lot less skeptical of some of this stuff after dealing with some of the strangest of interactions in circuits during my time here at Shure... Just something to keep in mind....that noise floor hiss you hear? That's the random vibration of the molecules in the circuit components you're using. Some of that noise (especially at low frequency) is actually due to quantum behavior. Now there's a fancy term! Haha, but the point is that audio performance is almost always at the limit of physics. Things can't get better because the world itself is the limiting factor. So here's a fun thought.....there's a ton of electromagnetic radiation in the air. What happens when that energy starts interacting with those sensitive molecules in our circuits? What impacts the ability for that energy to interact with our circuits? Working at a company that uses a lot of wireless technology, I have a lot of exposure to maths and stuff that describe that behavior. Anyways, I've seen crazier stuff matter. Think of that power cord like a big antenna. Or you can also think of it as a non-zero impedance for shared currents. Then there's the fact of reinserting a cable causing contact wipe which affects contact impedance. Fermilab runs a continuous current through all of their connections to prevent that oxidation from building. From a basic circuits understanding the power cord doesn't matter.....but this other stuff does. It's all this other stuff that keeps me employed actually because there's a crap ton of non-basic stuff to deal with. But ya, I agree the language is quite eccentric....but most artsy fart types tend to be on the eccentric side. This kind of flowerful language certainly makes life more interesting!

Ditto!

Distortion at lower frequencies tends to be related to power supply issues with the circuits I'm familiar with. None of my experience includes tubes though. Bias would be another place to look. Have you checked that nothing got jostled around during the move? Perhaps reseating everything and cleaning contacts might be an easy first try? I hope the shoulder feels better! I've been through that twice, so I know what it can be like. Is there at least an epic story behind the injury?

Haha, I certainly don't! Btw, there is a difference between 153dB with distortion limits and 153dB without distortion limits. The thing about distortion is that most of the non-linearities in a system get worse as you get louder. If you follow those trends back the other way, then you'll find that the distortion gets less as you get quieter. Generally speaking - a system that can go louder with the same amount of distortion will have less distortion when played back at a lower SPL. In other words, low distortion designs tend towards high SPL capability. However, high SPL designs don't necessarily tend towards low distortion. I've been thinking about what Roy has been saying (or more like not saying) and I think it's important to remember that distortion curves aren't linear. In other words, you hit a point in the output where the distortion starts getting bad very quickly (like when you bottom out a driver). Once you're below that knee, there are different distortion mechanisms at play. Perhaps that's what Roy means by talking about sound quality, but then I think maybe that gets into a conversation about design targets. Perhaps the high excursion drivers are giving up some performance at lower SPLs? I haven't seen that in the plots that Ricci has posted, but then the drivers Ricci has been measuring are in the over-priced category.

Haha, you're no fun. One of these days I'm hoping you'll take the bait

Hmmm...I don't ever recall looking at shininess and I certainly have never commented on it. I've always looked at things like Bl, CMS, Le curves, T/S params, and the resultant SPL, phase, and distortion characteristics, etc... all things that the rest of the audio engineering community is discussing and writing technical peer reviewed papers on. When I receive a quote that comes in higher than the competition, I'll usually ask our suppliers to explain the difference. It is often the case that they have included more capability within the part. Sometimes that capability is helpful for my application, sometimes it's not. I don't pretend to know everything about my own inventions, so I lean heavily on the experience of others to inform my implementation. I certainly don't go around making straw-man arguments in an attempt to belittle the competition. I learn and improve my designs by embracing the success of others. Perhaps you should be asking for more from your driver suppliers? Why settle for status quo?

If I trusted the dirty curves, then I think I would just stick with the Othorn since it is a smaller cabinet, cheaper, and has better numbers on paper....Are you saying we shouldn't trust the dirty curves? Or is that your point? The reason I want to hear a shootout is because I'm open minded enough to believe there are other numbers that might have a greater audible influence. You have but to point us to the data.... Here's a quick summary comparison: The published spec on the 1802-HLS for 1m ground plane is 130dB "calculated" with 1100W dumped into it. 102dB sensitivity with 2.83V input at 1m. Enclosure volume is 63.7 cubic feet. Cost = ??? (http://assets.klipsch.com/product-manuals/KPT-1802-HLS-Manual-WEB.pdf) The Othorn measured spec is 132dB at 2m ground plane measured with CEA2010 limits and 120V dumped into it. 100dB sensitivity with 1W input at 1m. Enclosure volume is 18 cubic feet. Cost = $1.5k (http://www.data-bass.com/data?page=system&id=81) One should add somewhere between 3 and 6dB to correlate a 2m measurement to a 1m measurement. The Othorn is also taking up 1/3 the total system volume. Upgrade to the Pro-5100 driver in the Othorn and you get another 2dB of output all around: (http://www.data-bass.com/data?page=system&id=95&mset=102) MaxSPL isn't the only story, but there's never been an exhaustive distortion spec of the 1802-HLS made public. The Othorn specs are there though....with normal SPL distortion numbers much lower than the Jubilee LF or Khorn LF. Back of hand IMD distortion calculations show that being lower too. How does the 1802-HLS distortion stack up?

We gotta get an 1802 into Ricci's hands so he can put it through its paces....and then we gotta find one of the crazy drivers to drop in and see how much more can be drawn out of the system. I really want to know how the 1802 stacks up against an Othorn. I hear all the good reviews from people, but I can't help but wonder if it's because it's the first time people have heard quality low bass before...Most of the direct radiator subs don't really perform the way the specs imply (what with their sliding high pass filters and nonlinear drivers, etc...)

Would you instead, prefer a jury of all engineers? Back when I mostly did criminal defense and DWIs, my best jurrors were EEs in breath test cases. Haha, probably because EEs understand how "well" (poorly) a lot of equipment actually behaves under the hood There's probably a lot of other cases though where a stereotypical engineer is probably a really bad choice....

So why aren't attorneys considered part of my peer group?