Bill Fitzmaurice

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.

That's the reasoning behind them, but for them to be effective the brace wouldn't be the typical one to two inches, they'd be four inches or more. Most of the rest of what you say is also incorrect. Not that you're at fault, you're just repeating what you've seen stated elsewhere. My comments are based on my own experience. It's pretty simple. Any and all of the bracing that's within four inches of the corners isn't doing anything, as that's where the cabinet is inherently the strongest and doesn't need bracing. Most of the spline bracing that's between the cross braces has minimal effect. That material would be better employed if it was used as cross bracing, reducing the spans between the cross braces. For that matter I don't see any bracing connecting the midway point of the sides, nor do I see a connection path from the top to the bottom. It's mainly a spline braced design, with the only significant cross bracing being those that connect the baffle to the back. Not in the least. If you didn't have the driver in hand and asked what to do due to your size constraints I'd have said build a Simplexx 10 or 12. Since you have the driver and the S15 is too large for you then you obviously have to take a different tack. Like the arguments about mixing cabs, mixing driver sizes and tube versus SS watts discussions on this topic always seem to end up in an endless back and forth with no resolution, so having said what I have to contribute I'll now bow out of the thread.

That's the theory, but in effect you're settling for the equivalent of 15mm when a single brace connecting the middles of two 12mm panels is the equivalent of using 24mm. I brace my cabs to the stiffness equivalent of at least 30mm plywood, while using less material to do it than other schemes. At least 2/3 of the bracing in that rotating model isn't adding anything to the structure other than dead weight.

If that's what Fearful bracing looks like I'm not impressed.

Yes. Every piece of bracing that's not actually connecting opposite panels is wasted material, cabinet volume and weight, doubly so for any that are in the cabinet corners.

If you compare the S15 construction, especially how the braces are configured and how the ports also work as braces, to what you've drawn you'll see no resemblance between the two. That's because spline braces are barely better than no braces. I stopped using them 15 years ago, other than in those instances where there's no other option.

It does apply. The midrange dispersion angle is the only factor where cone size alone affects the result. Where all the driver size baloney comes from is those who assume that larger drivers go lower, and smaller drivers go higher. They can, but not because of the cone size. It's from the other dozen or so factors that determine response, all of which can be jockeyed about so that there are many tens that go lower than the average fifteen, and many fifteens that go higher than the average ten.

A pair of 1x12 mains and a pair of 1x15 or 1x18 subs is adequate for the average room. Also, the subs should not be under the mains. The mains should be on poles in front of the mics to prevent feedback, the subs should be placed together close to a wall for boundary reinforcement and to prevent boundary reflection sourced response nulls.

No offense, but that's exactly what you don't want. Fifteens are for subs, or very high power three-way mains. Tens or twelves are best for mains, they have better midrange response and dispersion, and they're easier to lug. You don't want to use one sub with two mains. The demands on driver power handling, cone displacement and cabinet size go up as frequency goes down. That means the cab size and power ratio of subs should be about 4:1 compared to the mains.

I've worked with a lot of FOH engineers. The best were also recording producers/engineers and/or bass players.