Bill Fitzmaurice

Respect for James Watt demands nothing less. 👌

IME British cars of the 60s were paragons of reliability compared to Italian cars. Still, having owned an MG Midget it's a damn good thing you did a better job with Hurricanes and Spitfires.

So long as they're working it makes no difference. If series wired and one toasts a coil neither will work, so that would be a problem at a gig. If parallel wired and one toasts a coil the other will keep working, so it might get you through a night, but if that happens the cab tuning will be upset and there will only be one driver doing all the work, so it might die before the end of the set anyway.

They're well known for playing fast and loose with specs.

That's a safe bet...unless it's a Behringer.

That's not particularly helpful, since neither watts nor impedance define how well a driver will function in a given cab. It's not even a correct answer, as two 4 ohm drivers series wired also gives an 8 ohm load. In any event chances are if this isn't an exact match it's probably close enough: http://store.gallien-krueger.com/mm5/merchant.mvc?Screen=PROD&Product_Code=082-0460-C

There's a difference between within spec and optimal. Besides, amps aren't intentionally designed to give maximum power at their minimum rated impedance load, it just works out that way.

Heat. 100 watts into 8 ohms is 28.3 volts at 3.5 amperes, 100 watts into 4 ohms is 20 volts at 5 amperes. Where creation of heat in the amp components is concerned the primary source of heat isn't voltage, it's current. The same is true of driver voice coils. The lower the current the less heat generated. That's why power lines transmit at very high voltage, typically well over 100 kilo volts. Doing so minimizes current, which minimizes heat in the transmission lines, which minimizes the wire gauge required. It's also why you can run a 500 watt amp with a 16 gauge power cord. At 220 volts and 50% efficiency the amp will never draw more than 5 amperes. Put an amp with the same specs into a car with a 12v power supply and you need a massive mains cable, because you're now maxing out at 80 amperes.

Doubling the excursion of a driver results in a doubling of SPL. That requires doubling the voltage to the driver, which equals a four fold increase in power, which gives a 6dB level increase. One can realize that same 6dB by doubling the driver count driven with the same voltage. One may also realize a 6dB increase in SPL in an open space by halving the distance from the source to the listener. You also realize 6dB when you halve the space that the speaker radiates into, for instance when a speaker is mounted in a wall as opposed to being in an open field. The need for at least a 6dB difference to be meaningful is why going from, say, a 50 watt amp to a 100 watt amp is underwhelming. Sheer disappointment was my reaction when I went from s 50 watt Fender Bassman to a 100 watt Fender Dual Showman. That was when I was still in secondary school, it would be another two years before I learned the reason why I should have gone straight to the SVT.

Replace them with drivers that have the same Thiele/Small specs and frequency response as the originals. http://www.eminence.com/support/understanding-loudspeaker-data/

6dB is a doubling of sound intensity. 10dB is a doubling of volume. The 3dB voltage sensitivity increase you get from halved impedance has no effect on maximum output, as that's determined by cone displacement, which is unaffected by impedance. Amps don't breathe, and while some sound engineers may think there's an inherent advantage to 4 ohms versus 8 you'd be hard pressed to find speaker designers who share that notion. IMO one's better off to go with an 8 ohm cab, even if you are quite sure that a single cab is all you'll ever need, because things change. The time may come when a 4 ohm cab no longer works for you. Unless you make a change to a valve head that lacks an 8 ohm tap that won't happen with an 8 ohm cab.

Get an identical 2x10. Anything else is unpredictable. If you get something that has less displacement limited output than the 2x10 it will be a weak link, if you get something that has higher displacement limited output the 2x10 will hold it back.

Of course not. At least not according to Page 6 of the owner's manual.

I have a suggestion, but you probably wouldn't like it. 😨 Maybe we should make it a sticky/FAQ, thus ensuring no one will read it. 😩

You can't hear what isn't there. Aside from the limitations of the speakers the instrument itself doesn't put out that much in the fundamentals, any fundamentals, below 60Hz or so. If you want to have reasonably flat output to 30Hz your scale is going to have to be a tad longer, about six feet longer to be precise. As to the 40 versus 45Hz response debate, where are those figures from? If they're not taken from a measured SPL chart they're just so much piffle anyway.

The number of valves has little to do with the sound character, that's mainly determined by other components. The number of output valves has a lot to do with output power, but so does the valve type, as do the power supply and output transformer.

I assume you mean for PA, and the answer is the largest one you can afford and haul. Actually, the largest two. One mistake I see a lot is people trying to use subs with less capability than their mains. As I already stated the cab size and power ratio of subs should be about 4:1 compared to the mains. That makes 'ultra compact sub' an oxymoron.

With a 38Hz -10dB point it's nothing special as far as subs go. Not all bass cabs go that low by any means, but many do.

Try asking on the Hartke facebook page.

Open it up, see what it has for a woofer, buy another cab that uses the same woofer. It's probably an Eminence DII 2512 but you can't be sure without seeing the magnet.

Myth. Back in the 1930s an aeronautical engineer made that pronouncement. It would have been correct if bees fly in the same fashion that aircraft and birds do, but they don't, nor do most insects. Said engineer was a Frenchman, so his confusion was understandable. 😋 His theory never should have been published, but it was, and nearly a century later the myth persists. Bass gear myths are just as unfounded and just as pervasive.

You mean woofers, which takes us full circle. Next up: Six Degrees of Kevin Bacon.

It's very apropos. You can't judge a book by its cover, an athlete by his physique, or a speaker by the diameter of the cone. Or, to bring in another analogy, it ain't the size of the dog in the fight that counts, it's the size of the fight in the dog.

And Tom Brady was too slow. He still is, I could outrun him and I'm an out of shape 69 year old with arthritis. But one of the prime rules of American football is if you want a short career as a quarterback run with the ball. Brady doesn't run, and now he's not only acknowledged as the greatest quarterback of all time, he's the greatest football player of all time. I thought he might hang it up after winning six Superbowls. He still wants to go for number seven.

There is, it's called 'money'. To realize a given output at a given frequency it requires a given cone displacement. Cone displacement is area multiplied by excursion. You can get the same displacement with one average fifteen or with eight average fives. The fifteen will cost a lot less. The disadvantage to the fifteen lies in the narrow midrange dispersion. The cure for that is to use a fifteen only as high as its dispersion allows, typically to where the 30 degrees off-axis response is no more than 6dB down from the axial response, crossing over to a midrange driver to handle the frequencies above that. This isn't news to the hi-fi and PA industry, they've been doing this since the 1950s.