Edgar

The extra voltage comes from the interaction between the capacitor and the inductor. In a resonant circuit, the voltage across the individual reactive elements can be much higher than the driving voltage. The specifics depend upon the configuration of the circuit and the resonant Q.

That is usually mentioned in the context of class AB amplifiers, in which one device amplifies the positive half of the waveform and another device amplifies the negative half, with a small region of overlap in-between. There is a slight anomaly in the region where one device hands-off to the other; it is called "crossover distortion" for intuitive reasons. That crossover distortion is constant, regardless of the amplitude of the waveform being amplified. So at low power levels the amplitude of the crossover distortion is larger, relative to the amplitude of the audio waveform, than it is at high levels. Therefore, as a percentage of the total output, the crossover distortion gets lower as the power gets higher. As the power output rises, at some point the amplifier starts to clip, at which point distortion starts to rise again. So there is a point where the overall distortion percentage, from all causes, is at a minimum. That is the "sweet spot" that you mentioned.

The drone of four R-3350s in a B-29 ruined my father's hearing above 6 kHz, yet in his later years he could still hear the difference between cassette and CD.

As I recall, Cerrano ended-up saying, "(Forget) you, Jobo. I'll do it myself."

I use actual curves to create the models. Nice thing about that is that it allows me to invert transfer functions mathematically, instead of by trial-and-error. (I have some cool toys, too!)

And that is where things get complicated. It's one thing to implement an electrically perfect crossover network. It's yet another to implement an acoustically perfect balancing network (or whatever one chooses to call it). The magnitude and phase responses of a network consisting of resistors, capacitors, and inductors (or of DSP filters) is easy to predict. But drivers' magnitude and phase responses vary wildly, even within a small frequency band. There are (at least) two ways to deal with this: 1. Incorporate the driver responses into the design. So, for example, if one wants a 2nd-order rolloff, and the driver itself exhibits a 1st-order acoustical rolloff, then all that is needed is a 1st-order electrical rolloff. 2. Equalize the driver responses to flatness, so that the final acoustical response is controlled entirely by the electrical response of the crossover network. Of the two, #1 is easier to implement. #2 is far more difficult, but holds the promise of better ultimate results. DSP is making #2 feasible. The hard part is modeling the driver responses as transfer functions, so that equalization can be better than by trial-and-error.

Understood. "Period" alignment will avoid notches in the frequency response, but the transient response won't align. According to the paper that I cited (and others), though, as long as they're aligned within a small number of milliseconds (the exact number differs depending upon whom one believes), it won't matter.

For the paper, they used allpass filters to create the delay. So the magnitude response was unaffected, but of course the phase response reflected the delay.

From Audibility of Group-Delay Equalization, Juho Liski, Aki Makivirta, and Vesa Valimaki, IEEE/ACM TRANSACTIONS ON AUDIO, SPEECH, AND LANGUAGE PROCESSING, VOL. XX, NO. X, JANUARY 2021: "The listening test contained four different signals: the unit impulse, the pink impulse, a castanet recording, and a synthetic hi-hat cymbal sound. The two former signals are known to be the most critical for group-delay audibility, whereas the latter two resemble real-life musical signals and thus help to generalize the results better. Group-delay audibility was tested at the frequencies 500 Hz, 1 kHz, 2 kHz, 3 kHz, and 4 kHz. The results indicate that the audibility thresholds for local group-delay variation are less than ±1 ms [1 ms is approximately 13½ inches - Edgar] for the most critical signals, and approximately 1.5 ms to 4.5 ms for a local positive group-delay peak and between -1.0 ms and -2.3 ms for a local negative group-delay peak for real-life signals."

Cult of the Infinitely Baffled

In my home town there was a straight, almost flat stretch of road that had a posted 25 mph speed limit for about three miles, because there were several schools along the way. I was aware that it was also a speed trap, so I always drove at the limit. One dark evening about 8:00 I was driving this road, and I saw a pair of headlights behind me, coming up fast. The car got so close that I could no longer see its headlights in the mirror. So I slowed-down. The driver refused to back-off or pass, so I slowed-down more. Finally we were crawling along at less than 15 mph when he gave up, floored-it, and passed me. It was a local cop. You can guess what he was trying to do.

Anybody know if a pair of AK6 will fit in the back of a Jeep Grand Cherokee? Seriously, @Travis In Austin, for the eventual winner, is there a loading dock and helpful people available at the pickup point?

That brief reference was the only hit on the 18W54C that Google found for me.

Off-topic, but I noticed an interesting reference to "Beranek's Law" in that same article: "It has been remarked that if one selects his own components, builds his own enclosure, and is convinced that he has made a wise choice of design, then his own loudspeaker sounds better to him than does anyone else's loudspeaker. In this case, the frequency response of the loudspeaker seems to play only a minor part in forming a person's opinion." -L. L. Beranek, Acoustics, McGraw-Hill, 1954, p. 208.

See page 40 here.

I suspect that this is the dominant factor, by far. It's a simple fact that parts cost gets multiplied by 5 to 10 in the final retail price. Sure, an added resistor and capacitor may only cost a few dollars, but manufacturers cut costs wherever they can. True, but the voice coil still sees approximately constant voltage. Having a nearly constant, nearly resistive load makes amplifiers happy.

https://community.klipsch.com/index.php?/topic/204821-kp-3023002-high-frequency-speaker-intermittent-scratchy-sound-resolved-bad-cap-connection/&do=findComment&comment=2699406 https://community.klipsch.com/index.php?/topic/187697-measurement-systems/&do=findComment&comment=2436802

You forgot the cigarette lighter.

My '17 Grand Cherokee has a USB port into which I can plug a thumb drive. It can supposedly play a variety of music formats, though I have not experimented with it.

Must have been the supercharging.

Over the years I've worked for several non-profits ... none of them intentionally so. 😢

From Wikipedia: "The R-2800 was developed and modified into a basic sequence of subtypes, 'A' through 'E' series, each of which indicated major internal and external modifications and improvements, such that the 'E' series engines had very few parts in common with the 'A'." I wonder which series provides the best interconnects.

I liked the Cornwall 4 better, because of the excellent midrange. The La Scala bass was different, a bit more dynamic but not necessarily better-defined. In the rest of the spectrum my ears preferred the Cornwall. YMMV.

I had all kinds of problems with Firefox, so I switched to Opera and never looked back. Opera is Chrome-based, like Edge.

Thanks. That's a lot more response than I got, and I tried all of those methods.