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Everything posted by DrWho

  1. Haha 😃 I think the psychoanalysis was perhaps more internally focused as I found myself reading the ad several times trying to wrap my head around what might have the slightest bit of merit in the claims... I've recently been introduced to the concept of PIM (Passive Intermodulation Distortion) which occasionally turns out to be quite problematic in cell phones: https://www.anritsu.com/en-us/test-measurement/technologies/pim The basic idea is that you can get Intermodulation Distortions from the non-linearity created at the mechanical junction between two conductors. The fundamental mechanism isn't well understood, but there are plenty of empirical solutions for it. Perhaps we should try this magical elixir at work to see if our PIM goes away? 🙃 In other words....perhaps there is some merit.....and we wouldn't want others to think $599 was too cheap for the near perfection we enjoy in our homes...
  2. Perhaps the same thing that had you perusing in the first place? If you know what you're looking/shopping for, then you probably don't explore the fringes? So perhaps there's some unknown need not being met that is fueling a mind open to new discovery? And writing about it is perhaps a means to subdue this anxious curiosity?
  3. So is it safe to say Delphi was wrong? Waymo One is interesting, but it's in a dedicated city and I believe it has a team of people in remote control of the vehicle...so it's not fully autonomous although it looks like it. That autonomous system costs a lot more than $5k though.... But I do think the only autonomous vehicle model that makes sense is a rideshare / taxi type service. This way the burden of maintenance goes onto the vehicle owner, which is paramount to autonomous safety / feasibility.
  4. Standing waves have very little to do with headroom and overall output. My reference to PWK was about a Dope from Hope article or maybe an AES article where he talks about the mathematics of damping and his obsession with efficiency. The reason few companies dampen the interior of the cabinet is because it saves money. The audible effects are secondary to other larger concerns; same story with baffle edge diffraction. It is however very easy to measure internal standing waves (and baffle effects). It is also easy to hear the difference when they're mitigated. These things are in the last several percent of what matters to the overall sound quality. And it doesn't take much to get enough damping (point being don't over dampen because that's a waste of energy.... again back to the last percent of performance). The audiophile path is about tweaking out every last drop of performance. The speaker business path is about performance per dollar. That dollar might be better spent in other ways from an engineering perspective - especially in the pro cinema world where the effects are much harder to hear and dominated by the big screen in front of the speakers. On the other side of the coin, it's really cheap and easy to stuff a cotton pillow into a cabinet to hear the differences. If you want to be fancy you can use Owens Corning 703 and install it all proper like. I spent years measuring magical speaker cabinet shapes. They all resonate and have standing waves. Even the ones with magical shapes based on magical equations still resonate. The most direct engineering solution is damping. I wish it was a cooler story but that's the way it is.
  5. Nope. An inch for every foot is a general rule thrown around, but even that doesn't work. Sounds travels in all directions so you'll get tangential modes, etc. The best thing to do inside a cabinet is use absorption. PWK would argue that absorption reduces efficiency. Although that is technically true, I firmly believe the 0.1dB trade-off for way lower resonances is worth it.
  6. Haha mine too. There gonna be new content? (new speakers). I haven't been on the forum in years...
  7. Oh shoot - are you saying the X32 is outta the price range? What about the X32 Rack at $1k? The Behringer XR series isn't horrible, but he will quickly outgrow it. The XR12 is $250 and the XR18 is $600. They have fewer mic-pre's, but the same general USB recording capability, and can only be controlled via iPad.
  8. Oh, I forgot to mention the Allen & Heath Qu32. I believe it has a DAW controller driver available for it now. That might be something to consider in comparison to the X32. Ya, Dante is amazing - but you get the same functionality out of the box with a single USB2.0 cable to the computer. You're just limited to 32 channels. The Dante starts to make sense when channels counts get larger, or you're trying to send a bunch of digital data over a long distance. The USB only works when the computer is next to your console. I don't think the Qu32 has a Dante card option though. The X32 and TF5 definitely do. The QL consoles are a big step up in price from these other guys though. I think I'd personally make the jump from TF to CL unless I needed the automixer function built into the QL.
  9. I couldn't disagree more! The wireless interface that you get with an iPad removes one of the biggest shackles for a sound engineer: the location of the mixing console. I've been doing a lot of sound training lately and I gotta say it's soooooo much easier with the iPad. We get to talk around the room talking about and experiencing how the sound changes everywhere, and then learning to mix for the whole room. Walking up to a monitor on stage and hearing what the musician hears is one thing....being able to adjust it live brings entirely new meaning to the learning sound engineer. I use this all the time to teach "referencing the mix".....and learning how to correlate the booth mix to the stage mix for the musicians. Don't get me wrong - I'm a curmudgeon old fart that wants his analog knobs back, but the ability to move around while mixing is such a pleasant change of pace. I've intentionally done entire concerts (40 channel live recording mixes with realtime patching swaps, delay feeds, monitors, etc...) with an iPad because I could sit in a better location. However, I totally agree that it's best to learn the basics. Just because your console has comp/gates and crap tons of FX, EQ, and other processing doesn't mean you should be using it. 80% of the mix happens with mic placement and speaker configuration. 15% is faders and gain structure, 4% EQ, and that last 1% is the other 90% of the processing in the box.
  10. Behringer X32 I currently have both the X32 and Yamaha TF5. I also have extensive experience with just about every digital console out there. The short story that nobody wants to admit is that the X32 sound quality is very competitive at every price point. You might be surprised how many installations have ended up with the X32 - even when budgets weren't a factor. The biggest reason I recommend the X32 for dual live sound / recording is because you can also use it for DAW control. So instead of mixing on your computer with your mouse, you use the faders on the console to adjust the mix in the DAW. https://music-group.force.com/musickb/view/article/behringer/X32-Can-The-Console-Be-Used-As-A-Control-Surface-For-A-DAW The TF5 doesn't have that feature. The only reason I picked up a TF5 is because the user interface was more intuitive for the volunteer staff at my church. Both have iPad control, but the X32 iPad interface is way way way better. In fact, it's better than any other digital console out there. It's even better than the X32 console interface. As for the DAW, I would recommend Reaper....mostly because it's free. But if you're gonna spend money, then go with ProTools. It's what everyone uses these days and you'll be able to use anything else after learning it. You will probably come across recommendations for the PreSonus StudioLive and Soundcraft Si series, and you'll find a lot of people happy with them. However, I have yet to meet someone that has used all four consoles and preferred either the PreSonus or Soundcraft. They just have some really odd annoying quirks, and don't have anywhere near the processing power of the X32 and TF5. The next step up from those four would be the Yamaha CL5, but that's a totally different price point. Oh, and don't bother with the Behringer XR lineup. If you want to save money, go with the X32 Rack and a large screen iPad (older generations are totally fine for that). There's an Android app too if you do the android thing, but not for the Yamaha consoles.
  11. If you think this angle affects the point I'm trying to make, then I'd suggest I may not be communicating clearly, or maybe you're not understanding what I'm trying to get at.
  12. Show me one study that says Class III autonomy is safe. I've read two peer reviewed studies that show that it is less safe than no autonomy.
  13. Happens more often than you'd think, although that's not the point I'm trying to make. My emphasis is that it is possible to differentiate between the known and unknown: There are problems known about ahead of time Or there are problems due to ignorance (unanticipated variables). I take great issue when known problems are ignored - especially when human life is involved. And that is precisely what is happening here. There is also due diligence in trying to uncover as many unanticipated variables as possible, but that's detracting from my point. It's one thing to forgive someone of honest ignorance, but it's totally different to forgive someone of "willful blindness" or "cognizant recklessness". If someone like myself, with no official involvement with autonomy, is able to be informed well enough of the dangers of Class III autonomy, then how is it that Tesla and Uber are completely unaware? If they aren't reading this research, then they're not doing their due diligence to understand their design well enough....which is immoral. And if they are doing this research, then they're completely ignoring it, which is also immoral. Class III autonomy isn't a stepping stone. We don't need cars running around killing people to prove what we already know before a single car hits the road. If the airline industry engaged in the same willful blindness, then that was an unnecessary cost and absolutely should not be cited as an example of how we should expect these things to evolve. Give me one good reason why we shouldn't set the bar for our expectations higher? It has been my experience that when we set the design bar higher, that designs actually get completed faster.....and better. And then cost reductions follow very quickly because the designs are actually fully understood. Faster, better, cheaper....this has been my reputation for the last 10 years of official engineering, and has also been the reputation of those smarter engineers that I've been trying to learn from. Despite all the naysayers and low bar setters and lazy engineers, ignorant managers, etc.... There is a design philosophy better than this 'million of miles' nonsense that you're trying to tout.
  14. The annoying part about your scenario is that the statistics won't capture events like this because you weren't involved in the accident. That brain dead automatic braking system that will gloat about prevented fender benders won't accurately depict the fender benders it caused. I can't even begin to count the number of times an automatic braking system would have caused me an accident. The only people that believe in such systems are those that don't understand how to control a vehicle (and many of them aren't even aware that they don't understand). Maybe we should start making guns that have automatic aim and trigger pulling ability. This way the users of the gun don't have any responsibility to learn how to control their gun, and we can solve all violence that way!
  15. Exactly - profits at the expense of life. That reasoning was supposed to have died off after the industrial revolution, but apparently it's okay today if you fabricate a rockstar persona around the bad ideas.
  16. Nope, try again. That number is a lot closer to 0 miles when trying to prove something.
  17. You "suspect" because you want to believe in a fantasy. The guessing/betting was happening with the brain dead engineer that designed the system. It's all built on false principals / false assumptions. All this talk about things in the name of safety, and yet you believe in crap like airbags and automatic braking, yada yada yada.....and yet today we already have real solutions to the safety problem that don't require any of these finicky gadgets. But far be it for the luddites to entertain real safety.....they're too busy chasing a fantasy.
  18. DrWho


    On paper the Othorn has more output, and has a smaller cabinet. I don't know about low level distortion but at higher outputs the Othorn should win. It'd be interesting to put a better driver in the KPT-1802 and compare against the Othorn. I would expect the ports on the 1802 to be the limiting factor. Either way, I'd love to hear a side-by-side shootout. The KPT-1802 is a better engineered design from a business perspective, but still costs more than the DIY approach. Honestly though, due to how our ears work at lower frequencies, I think it'd be difficult to tell the difference. The 1802 probably digs a touch deeper in a real world home application. The annoying thing with tapped horns is they don't benefit from room gain in the same way as other designs.
  19. I don't recommend using a transformer for subwoofer duty.....they tend to roll-off the low-end (unless you get something really large and expensive). Honestly, I would start with the unbalanced connection. If the subwoofer was designed well, then you shouldn't have noise coupled through the connection. A good unbalanced solution will outperform a lousy balanced solution all day long. If you're pulling cables through the wall, then spend the extra hundred bucks to run conduit so you can pull new cable. There are two mechanisms for noise injection into a cable: 1) Currents along the cable shield. 2) Radiated noise coupling into the "loop antenna" (the structure of the signal and signal reference). In an XLR cable, your signal reference and signal exist on a twisted pair, which is then shielded by a third ground shield. In an RCA cable, your signal reference is the ground shield for the signal. Since the ground shield has some impedance, currents flowing along the cable shield create a common mode voltage. With a balanced connection, the common-mode noise gets cancelled out (the key is that the currents see the same impedance so that the voltages are the same on both legs). With an unbalanced connection, this current gets converted directly into the signal voltage. The only way to reduce the voltage is to lower the impedance (or improve the power supplies so that they leak less current down the cable). These noises tend to be very low because the cable impedance is low (<1 ohm ideally) and the leakage currents are low (~1uA)...roughly -120dBV. Most low noise inputs are roughly -90dBV white noise, maybe -110dBV on a really low noise circuit. If your noise is radiated (#2), then you can solve this with a shielded twisted pair for the RCA. The shield only connects to the source (the subwoofer output of your receiver), and then the twisted pair connects to the signal and ground on the receiving end (your subwoofer input). This routes the noise currents into the low output impedance of the source, which keeps the noise off the twisted pair. And by using a twisted pair, any noise that gets through the shield is common to both the signal and the ground cable, which helps provide some common-mode rejection. Some refer to this as a directional cable, or maybe a "balanced rca" cable. The ~10ohm output impedance of your source attenuates the field currents a lot better than the 10k input impedance on the sub. Summary: Use a shielded twisted pair cable for the subwoofer cable, and start with the shield connected on both ends - if you're still getting buzz, then try lifting the shield at the subwoofer connector. If it gets worse, then the problem is conducted - and your best solution would be to find the three-prong power cable that is causing the problems (and lift it, although lifting it is unsafe for chassis ground faults). The usual culprits are the Cable TV lines - and the transformer isolation for those is a lot cheaper (and better) than a transformer for a low frequency audio signal. Sorry for the brain dump. Don't forget to run conduit...1" PVC should be sufficient (and leave the pull cable in the pipe when you're done so you don't have to snake it twice).
  20. True story - and I'm even relatively local to Madison, WI.
  21. I think the normalized plots are misleading....it would be better to overlay the actual total impedance, and you'll find the exponential horns have more loading....even at lower frequencies (below Fc). The issue is that the value of "1.0" for the exponential is much higher than the value of "1.0" for the conical.
  22. Hmmm, interesting....now that makes a ton of sense. Is that now the plan of record for landing the crew on Mars? I just watched a documentary while on a recent flight talking about the physics of landing with Mar's atmosphere, and they hadn't identified a solution yet. I don't recall them talking about using rockets on the landing though - I'll have to watch it again. The plan of record at the time was a Rube Goldberg experiment - this rocket landing approach would be way more elegant than the other methods they were proposing.
  23. Well that would be the snarky ignorant reply..... SpaceX has the following on their website: http://www.spacex.com/news/2015/06/24/why-and-how-landing-rockets The question not answered in my mind is why that is the best approach. I don't think anyone questions the merits of reusing a rocket. I understand that the raw fuel "material" itself isn't that expensive (proportionally speaking), but requiring a crap ton more fuel compounds other scaling issues - which ultimately obfuscates the true cost increase of having to pack the extra fuel. Basically, the rocket is a lot bigger (and therefore way more expensive) in order to accommodate the extra fuel needed for landing. Obviously "rocket scientists" are working on this stuff, so it's not like they're not brilliant and aware of tradeoffs - but the space program seems to have a constant stream of overly complicated everything. I have a hard time fathoming that this is the most elegant solution to saving a rocket....especially when my small mind can dream up all sorts of other approaches that seem way simpler, cheaper, and move the cost out of the rocket entirely. I am absolutely not saying I could do a better job, but I would think it'd be possible to find some further explanation after doing my diligent research. Unfortunately Google searches on this subject are flooded with the nonsense propaganda from Musk who likes to over-exaggerate and showboat about everything. And then any interest in further discussion is squelched by condescending remarks from someone blinded by the kool-aid.
  24. I have a pair of Chorus II midgranges, complete with drivers sitting around doing nothing. You looking for an experiment? The Chorus II midrange driver has a phase plug built into the driver - it's separate from the horn which makes mating different drivers more complicated. The horn itself is a standard tractrix expansion (or so I've been told). It's starts with a round conical-looking throat that transitions into the rectangular mouth. While looking for pics of the driver, I came across this thread: https://community.klipsch.com/index.php?/topic/169052-k-61-k-in-a-cornwall/ But here are some pictures of the diaphragm assembly: https://www.ebay.com/itm/Klipsch-Factory-Speaker-Midrange-Horn-Driver-Diaphragm-K-59-K-K61-K-62-K-127120-/141219105169 I would probably go with a K-510 before the Chorus II midrange, but then I also understand there's a big price difference there too.
  25. I'm not sure I agree with that. I think there's more to life than "making money" or "focusing on pleasure".... I think they are byproducts of living a more fulfilling life.
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