Bill Fitzmaurice

Cone area alone is almost meaningless. What matters is displacement, cone area times excursion. Most eights have less excursion capability than most twelves. It's easy to come up with a pair of eights that would have half the displacement or less of one twelve. All things considered displacement is a far more important spec than either driver size or thermal power capacity. It's the equivalent of going into a pub and ordering an ale by the color or the price, while not knowing whether the container is a pint or a dram.

It appears that the weight reduction is from going to thinner plywood of a lightweight species, probably Italian Poplar. Going to 12mm instead of 16mm would reduce weight further, but requires bracing that would drive up labor costs to install. I do all my DIY cabs with braced 3mm, 6mm and 12mm, as there are no labor costs. 😊

We still use the standard set by Henry VII on our side of the pond, whilst you've adopted that Napoleonic piffle. Makes one wonder who actually won at Waterloo. 🙄

Speaker size alone doesn't indicate what a cab is capable of. GR Aero doesn't publish the technical data which does tell one what any cab is capable of, so the only way to know for sure how these cabs compare is to take the time to try them, side by side. That said, all else being equal a 1x12 will usually outperform a 2x8. The problem is that all else is never equal.

It's better, but the gains by switching to the Beyma would still be minor, as would be going to a 4 ohm driver. The limiting factor here remains the amp.

Ported with a suitable driver might work better with at least 60 watts. With 15 watts it won't. You're in the realm of asking if it's worthwhile to put a set of Dunlop racing tires on an Nissan Qashqai. You may, but it won't go any faster.

If you just look at the specs it seems worse than it is. I modeled it and it's not bad. In a sealed box it's considerably better than the Beyma, which has too low a Q to work well sealed.

That driver isn't all that bad. To get something significantly better you'd pay at least three times as much, and with only 15 watts you wouldn't know the difference anyway. An eight would work better, but not in that cabinet. Look at your bass. It doesn't have a 24 inch scale, it doesn't have a .052 E string. That's because the scale length must be long and string diameter must be large to create long wavelength low frequency tones. The same physics of sound dictate that low notes at club levels from tiny speakers do not come.

One can't recommend a different driver without knowing what you have now. But don't hold you breath about a different driver being significantly better. The main difference between inexpensive and very expensive is how much power a driver can handle before exceeding both electrical and mechanical limits, and with only 15 watts you're probably already there.

Agreed, 100w and a minimum 10 inch speaker is the least that I'd consider. That may seem like a big jump, but to sound twice as loud as 15 watts you need 150.

Right. And part of the reason why an 810 seems to have more treble is because the height of the cab places the drivers up where you can hear the directional high frequencies that otherwise pass by below your waist. There is no characteristic sound based purely on driver size.

Do you know how to drain the power supply caps and why you have to?

I'm guessing that a power supply cap solder joint has come loose. When the amp is sitting normally the cap is out of circuit, when tilted it's in circuit. I'd re-solder those, then test the power rails to be sure there's no pulsing of the DC. Be aware that the caps will store a considerable charge, so if you don't know what you're doing don't mess with it.

No matter what's being played through youtube clips always sound like the teeny tiny speakers in my laptop.

At full power most amps don't put out twice the power into a halved impedance load due to power rail sag, but unless you've got a particularly anemic amp you'd seldom if ever push it at full power. At more reasonable levels the 6dB figure is spot on. The reason you get 6dB is because the amp puts out the same voltage into two speakers as it does into one. That results in doubling the system cone displacement, which gives 6dB additional output.

That's not how it works. How it does work is that by adding the second cab identical cab stacked on top of the first, with no changes to any of the amp settings, the output will go up by 6dB. That gives the same result as would quadrupling the power into the one cab, if it could take it.

Power Alley is most problematic in small venues, not large. Unless they're separated by at least 15 meters subs should usually be clustered, and wall loaded. You can't wall load a sub that's under a main that has to be in front of the band to prevent mic feedback. But to be frank your entire setup is AFU. Fifteens are for subs, not tops. Tops should only be run above 100Hz, and above 100Hz the only thing fifteens give you is poor midrange dispersion from cabs that are too big and too heavy. Then there's the matter of driver displacement and cab size. The demands of both double with each octave lowering of the pass band, so to match up with a pair of 2x15 mains you'd need at least eight 1x15 subs. It's just like an iceberg. What you can see above the water is the mains, what you can't see below the water is the subs. Of course one wouldn't expect that you'd make wholesale system changes at this point, but since you now have a pair of subs the next logical move is to get rid of the 2x15 mains in favor of a pair of 1x12 mains.

That's not an option.

https://mediadl.musictribe.com/media/sys_master/hdb/h4f/8849699995678.pdf

You still need a crossover. EQ doesn't provide the necessary roll off slope or depth of out of pass band attenuation.

A load that's too low in most cases will trigger protection circuitry that shuts the channel down, often resetting itself after the heat that caused it to shut down dissipates. If you don't have protection circuitry, rare these days, the amp could blow. You should not be using subs plus mains on the same channel . You should be using an electronic crossover and a separate amp for the subs, or one channel for the mains and one channel for the subs if the loads per channel aren't too low.

If you like the tone of your Ampeg add another. If you don't find something else entirely.

That capacity is thermal, not mechanical. The average cab has a mechanical capacity no more than half the thermal capacity.

It might be OK, since Gibson has no meaningful presence in the guitar amp market. If they'd been bought out by Fender you could expect the brand to disappear.

In semi-defense of guitarists they need to overdrive the speakers for tone. The problem is how loud that's going to be with even a 1x12, let alone anything larger.