Bill Fitzmaurice

You wouldn't hear much, if any, difference if the tops aren't reproducing sufficient lows. However, they're still receiving the low frequency information, so the amps are producing low frequency power and the drivers are taking that power, which stresses both the amps and the drivers, while the THD of the tops will be higher than if high passed. You've got nothing to lose with high passing, and potentially much to gain with respect to amp and driver headroom and lower THD, so it should be done.

Knowledge is like good food and drink. It's best when shared. ☺️

One would be sufficient. ☺️

Steel is highly unlikely, tinned copper is common.

If not identical you can have one coasting while the other is stressed.

When the D140F was introduced front mounting was rarely use, so they didn't come with a gasket. IMO that driver pre-dates the cab, so it probably wasn't a factory installation. The fact that it was reconed adds to that opinion. In any event yes, you should clean it up and use a new gasket or 2mm neoprene gasket tape.

Don't. Spring connectors work by deforming the copper wire, which prevents it from vibrating out. If tinned it's too stiff to deform. I've been using spring connectors for at least 30 years, have yet to have the wire pull out. Victor Wooten lost all credibility when he started endorsing huge, and hugely expensive, power cables that don't do anything. I'm surprised he doesn't have a Shakti Stone atop his amp. Maybe they can't afford him? 😮

Neither do audiophools who spend a fortune on oversized cables that don't do anything other than depleting their bank accounts. 😉

It's far larger than the wire in the voice coils. 😎

I haven't used Tolex since the 1990s but if I did I try this to keep it looking good, it works wonders for my car: https://www.amazon.com/dp/B01AAZ1OAE

That is a possibility, impedance rises with temperature, but it would take a very sophisticated DSP to incorporate that feature.

Thermal protection only applies to the amp.

The only method of driver protection that really works is limiting the voltage output of the amp. It's SOP in touring pro-sound. The voltage is limited so that neither the driver Pe nor Xmax is exceeded. Outboard DSP can incorporate it, as can onboard. Whether or not a given powered speaker has it or not you can probably determine from the owner's manual. If it has it they'll say so. If they don't say so it likely does not.

Since the dome is paper it was probably re-coned with a 2226 kit. Not ideal, but it still works. As to the wife, a man should have as many amps as his wife does shoes.

Judging by the vintage if loaded with JBL it's probably an E140. If you don't see a 10cm diameter aluminum dome it's not JBL.

According to Fender: Compact and lightweight (16 pounds) sealed enclosure with removable grille. Given the size and power chances are it's an inexpensive high Qes driver, so there wouldn't be any point in porting it.

Thanks. Celestion hasn't been known for PA drivers for DIY but they're getting very strong in that market.

They're very light, as they are built from 12mm plywood and the drivers are neo. The exact weight depends on the plywood species, but they're going to be lighter than most commercial offerings. Like any sub they should cross to the mains between 80 and 120 Hz.

Celestion hired me to design compact lightweight enclosures for their TSQ 1845 and 2145 drivers. They're now posted on the Celestion site as free PDFs with youtube videos. https://celestion.com/blog/build-this-18-inch-bass-reflex-enclosure-featuring-the-tsq1845/ https://celestion.com/blog/build-this-21-inch-bass-reflex-enclosure-featuring-the-tsq2145/

They shouldn't. The room affects the PA of course, but standing close enough to the PA to take the room out of the equation your in-ears should sound very close to the same.

Allison Effect, the cancellation from the reflection off the rear wall. To prevent it the subs must be close to the wall, the mains far from it. When both are the same distance away it's unavoidable. See above. Since you can put the sub anywhere that relieves some of the space concerns. By dint of using a bass combo as a sub it is a sub, and the same placement rules apply.

Because the sub probably has more available output from 60-100Hz than the tops. Crossing lower than 100Hz with tops that are on stands also brings floor bounce cancellation into the equation. No, as that results in directionally locatable frequencies coming from the subs. Then you lose the ability to put the subs anywhere, which should never be below the mains unless there's no alternative.

Once again, port shape ...doesn't matter, though narrow slots should be avoided. That's as far as sound is concerned. From a construction standpoint I use corner ports, as they do double duty as bracing for the baffle, top, bottom and sides.

That being the case you don't need the subwoofer bottom cab of a Bose clone, even as meager as it is. You do need two speakers, for even coverage. Size being the issue a pair of powered 8" or 10" loaded mains will do, and you'll get a lot more value for the money with those than with mini line arrays, which tend to be terribly over priced. Another advantage is you can use them with your existing sub when the need arises, and add them to your regular system for outdoor gigs.

Bracing is seldom unnecessary, unless you're building with 36mm plywood. My personal cabs are built from 3mm and 6mm plywood, which is possible because they use necessary bracing. Sure, if you want state of the art circa 1984. 😲