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Edgar

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Everything posted by Edgar

  1. Don & Kathy's House of Music, Saint Louis, MO, around 1977. Klipschorns. Fleetwood Mac, "The Chain". The kick drum in the opening gut-punched me like I'd never experienced before. Later, during the bass riff toward the end, I could almost see the bass notes rippling through the room. Very impressive to an 18-year-old (at the time).
  2. The volume control can be implemented as a multichannel analog attenuator, after the crossover, or in the mathematics of DSP crossover itself. In theory, analog volume controls are superior to digital volume controls. Analog controls reduce the noise level along with the signal level. Digital volume controls reduce the signal level but the noise floor remains the same (and then, only if the signal is properly dithered after attenuation). In practice, as long as the noise floor of the DAC is below the noise floor of the listening room (or of the other electronics), it is a non-issue. And with modern DACs, this is fairly easy to achieve. In addition, digital volume controls are superior in terms of channel tracking and attenuation accuracy.
  3. In addition to being severe overkill, it can actually backfire on you. It is not uncommon for a Class-AB amplifier to have considerably more distortion at very low power than it does just before clipping. A fairly typical example of that is shown in Figure 3 here. With super-efficient speakers like the Jubilee, you're likely to spend nearly all of your time below 1 Watt, where distortion is at its highest. Other amplifier types may behave somewhat differently. Class-D can be better or worse, depending upon implementation. And you're probably not considering a 500 Watt Class-A amp.
  4. OK I get that, but what if I showed up at his door, in person? The location in the St. Louis ad was only about 50 miles from me. What would have happened if I had called his bluff and wanted to hear the items before buying?
  5. Still worth a double-check, though. For just a few dollars, that gadget is a nice thing to keep around anyway. Ah, well, that eliminates one possibility. Still useful as general knowledge. Another thing to check: I once encountered a situation where everything on one particular circuit acted strangely. The wiring checked-out OK. When I looked at the breaker, I found that it had tripped, but only partway -- literally the lever was partway between "ON" and "OFF". There was just enough continuity to satisfy the receptacle-testing gadget, but under load things got weird. I reset the breaker and all was well again.
  6. Neither question is dumb; both are standard procedures in a case like this. Also check to see if the "hot" and "neutral" connections in the wall plug are reversed. One of these will do the job for you. I have a (solid state) amplifier that only hums when the ground is lifted. I have another (solid state) amplifier that always hums unless I use one of these.
  7. Ah, well, then I really am naive. 🙁
  8. I'm probably naive, but I could never tell whether Captain Beefheart's failure to deliver was intentional, or was because he overestimated his own capabilities.
  9. I've never understood how such a scam works. What, you call the guy and he says, "Haha, fooled you! They really don't exist. Don't you feel stupid?" What's the point?
  10. I thought it might look too good to be true, but you never know.
  11. https://stlouis.craigslist.org/ele/d/washington-klipsch-cornwall-4s/7716926490.html No affiliation.
  12. It's a single shot. During totality I kept shooting as fast as my camera would allow. It was set to auto-bracket (+1, 0,-1) F-stop, and this was the best of that particular trio. Canon T3i with an old (non-autofocus) Tokina 100-300mm zoom set to 300mm and focused at infinity. I didn't record the aperture setting, but it was probably around F8. EDIT: If I remember correctly, I based my exposure upon info here.
  13. From the 2017 eclipse, taken in DeSoto, MO. You may use it without compensation if you like, but credit the photographer (me).
  14. I've been using an earlier version of this (USB2 instead of USB-C) for several years. It has been 100% reliable. I'm not sure that there are XMOS drivers available for Android or iPhone, though -- I recall having to search a bit for Windows drivers.
  15. Well, Jefferson City, MO and Springfield, MO are only a couple-hundred miles apart. But Gainesville is in Florida.
  16. Hmmm ... also shows up in Springfield, MO craigslist. Another scam?
  17. https://columbiamo.craigslist.org/ele/d/jefferson-city-klipsch-cornwalls-iv/7662881877.html No affiliation.
  18. In my designs, it was the "natural" frequency in the prototype Laplace-Domain transfer function. That frequency may not show any obvious relationship to the 3dB frequency or the "mid" frequency, depending upon the values of the other parameters -- for example, what is the "3dB" frequency in a shelf that only boosts 2dB? But my definition is at least self-consistent.
  19. It looks like Xilica used the parameter definitions for shelving filters from the RB-J Cookbook. Robert Bristow-Johnson defined the "shelf slope" parameter as "... (for shelving EQ only). When S=1, the shelf slope is as steep as it can be and remain monotonically increasing or decreasing gain with frequency." Years ago I designed a DSP package for EV that included shelving filters. I do not know if they continued to use my definitions of the parameters in subsequent products, but if they did then you can assume that the EV "shelf slope" parameter is equal to 1 in all cases. The difference between the "6 dB" shelf and the "12 dB" shelf is that the 6 dB version is based upon a 1st-order transfer function, and the 12 dB version is based upon a 2nd-order transfer function.
  20. True. I just find amusing the reverence for the 1970s gear that has developed on some of the audio forums. (Not necessarily this one -- I haven't really paid attention, other than to chuckle a bit when I see it.)
  21. Funny thing is: back in the 1970s we considered that stuff "mid-fi". How times change.
  22. In 1993 I developed a digital signal processing algorithm that required so much computation that I thought I'd never see it run in "real time" during my lifetime. By about 2015 it was running in "real time" on a telephone. What a great time to be an engineer.
  23. Actually, no. It's a TracFone. I bought it outright for $59. I average about $7 per month for my usage style -- talk and text only; data are available but I don't use them.
  24. Do phones really cost that much nowadays? Wow, do I ever feel like a dinosaur. My last phone cost me $59, and yes it's a smart phone. Does everything I need and a few things I don't. But then, I use it almost exclusively for phone calls and texts, the exceptions being those few new electronic devices that require a smart phone just to set-up.
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