Bill Fitzmaurice

That was done to save amps from being cooked by impedance loads that players employed because they didn't know better. I will confess to having done that, running 2 ohm loads with Fender amps that wanted no less than 4 ohms. But that was the '60s, we did all sorts of weird things then and managed to survive, and those Fenders were built like a Centurion tank.

Not really. The only time it might is if your amp is so underpowered that it can't drive the 8 ohm speaker to it's full displacement, which would be rare, like with a 25 watt amp and a 200 watt speaker. A 4 ohm 15 makes some sense if it's paired with a 410, or even a 210, to get the sensitivity of the 15 high enough to match well with the 210/410. But then you'd need a 2 ohm capable amp, not to mention the inherent flaws of mixing speakers. Oops! I did mention it. 😲

It's not about watts, it's about voltage sensitivity. That's 3dB higher with 4 ohms, so with the same amp settings the 4 ohm speaker will be 3dB louder, assuming all the other T/S specs are the same, which they seldom are. 3dB is audible, but just. As for maximum SPL that's mainly determined by the cone displacement, T/S spec Vd. If Vd is the same maximum output will be the same, again if all the other specs are the same, which they seldom are. The 3dB increase in voltage sensitivity comes at the cost of drawing twice the current, which some amps don't deal with very well.

If that's with guitar amps the speakers are contributing to that clipping, by virtue of the short xmax and break up modes of guitar drivers.

https://www.midbass.com/how-to-understand-ts-parameters/

Upgrading is possible, if you have a basis for comparison. At a minimum that requires testing your speakers for frequency response, and knowing their T/S specs.

At least we're not using cubits, though they did manage to build the pyramids with them.

In the US metric hardware, as in nuts and bolts, have pretty much replaced Imperial entirely. It started with cars, when the best selling cars in the US were all Japanese, and the US manufacturers were forced to follow suit. It became complete when almost every product made was of Chinese origin. But as for going full metric about the only product that has done so is alcohol.

So when I watch British TV programs (which is almost every day) why do they keep referring to feet, pounds and miles per hour? 🤔 It reminds me of the story of the man who was confused while visiting Quebec. The faucets in his bathroom were both marked C. When he asked the front desk why they both said 'C' the clerk replied 'the one C stands for Cold. The other stands for Chaud. We are bi-lingual.'

Burying a post at the end of an unrelated zombie thread tends to be unproductive. You should start a new thread.

Pretty much any two cabs together will sound better than either alone. The only way to know if Cab A plus Cab B is better than 2xCab A or 2xCab B is to try all three combinations side by side. That's not an option for most.

Cheap connectors are the likely problem. Are your cables equipped with Neutrik? If not replace them- the connectors, that is, not the cables.

It only delivers 180w into 8 ohms, so you won't have a lot of headroom. The i Pro 600 V2 is a better match.

Everywhere. It can't damage anything, and will displace any residual moisture

True, so I'd spray the inside with contact cleaner, including in the pots.

Hoffman's Iron Law .2 : Goes loud, goes low, is inexpensive. Pick any two, but you can't have all three.

You left out the pedals. That makes it eleven, and not in the good way. 😒

Mechanical coupling, yes, as I noted to keep the speaker from dancing. Acoustical coupling, or decoupling, no. Many of those seen on silly expensive speakers look like they must do something significant, and it's mainly audiophiles who fall for the scam. It's quite odd that so many of those claiming to have 'golden ears' listen with their eyes. 🤔

24 hours is more than enough. For many years my valve amps took the ride to the gig in the back of a van, where there was little to no heat, while being stored during the week in an unheated shed. Mind you the over night temperatures in my area during winter are -5C and lower, often dipping to -20C. The time between when my amp got into the heated club and when I fired it up was about an hour. I never had a problem.

They were very good friends with Ox, Squire and Lemmie. 😉

Cutting mids will lose you in the mix, but using a pick restores them compared to fingers. I use a pick most of the time, as I like a strong mid presence, but when I want a mellow tone I switch to my fingers.

Thicker foam of lower density can be beneficial on particularly soft stages. But too thick can result in the cab rocking. Spikes don't do anything useful from a sound standpoint. Where they can be beneficial is on a carpeted floor, gripping through the carpet to prevent speaker 'dancing' at high power levels, especially long-excursion subs. The quasi-magical properties attributed to them by some are just more audiophile piffle.

Mechanical decoupling is an audiophile myth. What vibrates the stage is the acoustical output of the speaker, not mechanical coupling from the cabinet, which would be the tail wagging the dog. What can occur is that the vibrating stage will cause the cabinet to vibrate. The best way to prevent that is with a piece of yoga mat. More on the subject: https://ethanwiner.com/speaker_isolation.htm

Translation: It has low sensitivity. To put that into context a 3dB sensitivity difference requires twice the power for the same output. 6dB requires four times the power. IMO knowing sensitivity is very useful, as are frequency response and displacement. Without knowing these one cannot make an objective comparison with other products, and that's the point. 😒

There's no replacement for displacement. Well, there is, horn loading, but then you're talking about a much larger cabinet. The displacement of a premium 4" driver is around 30cc. A middle of the road 8" is around 75cc, a middle of the road 10" is around 150cc.