Bill Fitzmaurice

It's more likely to have a 15B.

Ampeg speaker power ratings are conservative, so I wouldn't be concerned.

What I can't do with four strings doesn't need to be done. 😉

True, but that was 30 odd years ago, when very few mainstream manufacturers used premium drivers. JBL, Altec and Gauss were in the same league, hardly anyone used them. EV and JBL both made cabs back in the 70s, perhaps into the 80s, which were far superior to Fender, Ampeg and most others. They never sold well, so they were eventually discontinued. That's because back in the day you never bought amps and cabs as separates, you bought them as a matched set. Mesa was one of very few that sold an amp and cab set loaded with premium drivers. Sunn was another. The TL606 was good in its day, but it was optimal with 55Hz tuning, which gave a 60Hz F3 and 45Hz F10. The step down option lowered the Fb to 40Hz, which lowered F10 to 40Hz but it raised F3 to 70Hz, so it didn't work all that well.

Low end response is 1/3 driver, 2/3 enclosure. If the enclosure won't support deep bottom no driver will give it. BTW, the Kappalite 3015 response isn't much different from the 15B. The 15L is weaker in the lows, being optimized for guitar.

Usually hiss is created early in the signal chain, so gain amplifies it, making it worse as the gain is increased. If it's there no matter where the gain is set then it's taking place further along the signal chain. That could indicate a fault in the amp, perhaps something as simple as a broken PC board trace or a cold solder joint on a component. That's something that could have occurred when it was shipped. I'd call around to see if a nearby store has one that you could compare yours to. That way you'd know if yours is within spec.

A compression driver is a type of tweeter. Back in the early days of SS they were much noisier than tubes, but I'm talking 50 years ago. Tubes aren't inherently noisy. I wouldn't say Ampeg is limited at all. That's because it's not an issue. Quite right. Other steps for minimum noise is to turn down the gain, turn up the master, and turn off the ultra high switch.

The Bravo 112 cabinet volume is perhaps half that required for good results with electric bass.

It may not, the loop could be on the back side of the input stage but before the gain control. The manual should say.

The mass of the steel of the frame is dwarfed in comparison to that of the top and bottom plates, so it's a minor concern.

Cast aluminum baskets are used for two reasons. With heavy ceramic magnets it's to be stiff enough so that the frame doesn't flex. With neo magnets it's to act as a heat sink. Steel is OK with lighter weight ceramic magnets, and with lower power neo magnet drivers that don't require much heat sinking. Eminence uses steel for their 150w Basslite series, cast aluminum for the 250w and higher Delta Lite and Kappa Lite. Where frame stiffness is concerned there are two requirements for very high sensitivity. One is a high flux magnet, the other is a tight magnetic gap. If the magnet weight causes the frame to flex it can cause voice coil rub with a tight gap. That was a problem with the 1968 Electro-Voice SRO 15, later re-badged as the first generation EVM. It had a cast aluminum frame, but with only four spokes, so it would flex under the weight of the 16 pound magnet structure. The second generation EVM cured that by going to an eight spoke frame.

There's very little difference in the sensitivity of different cabs, but a lot of difference in their response and mechanically limited power. The only way to be sure of a good match is with identical cabs.

There's not much sensitivity difference between different drivers. Where going loud is concerned that's a matter of excursion/displacement, which is pretty much a matter of price. Longer excursion/higher displacement drivers cost more than shorter excursion/lower displacement drivers. The only manufacturer I'm aware of that reveals displacement is Barefaced, which doesn't aid in making comparisons, since you don't know the displacement of other brands. But suffice it to say that no other brand exceeds Barefaced, and very few, if any, equal it.

Download the manual. It may have a thermal switch.

A good example. Xmax of the Greenback, and for that matter most guitar drivers, is very short. The result is high distortion at moderate power levels. This relates to us in the form of the original 1969 SVT. It was loaded with short xmax musical instrument drivers, as there were no long xmax tens in 1969. Even eight of them couldn't run clean with the 300w SVT head. The cabs were rated at 240w thermal, while the mechanical capacity was at best 120w. That's why those who could afford them used the Ampeg recommended two cabs.

In most cases the xmax isn't available. The mechanical power limit of drivers averages around half the thermal limit. Some are higher, some are less. Some even have a mechanical capacity equal to or greater than the thermal. But those are high cost premium drivers that are seldom seen in electric bass cabs. Here again don't take my word for it, verify it yourself with speaker modeling software. As a for instance, the Eminence Deltalite II 2510 is the most popular neo ten inch platform. The thermal rating is 250w. The mechanical limit in the critical 80-100Hz region is 100w. And the 2510 is better than most. The most popular ceramic ten platform is the Eminence Beta 10. The thermal limit is 250w. The mechanical limit is 60w.

No doubt Ampeg is one of the more honest manufacturers. Their power ratings are conservative. But the fact remains that without xmax or Vd one simply cannot calculate max SPL. Try it yourself, using any of the common loudspeaker design programs, leaving xmax/Vd out of the parameters. You can calculate response, impedance, phase, group delay, port velocity, but when you go to the max SPL chart it's left blank for the lack of the required specs. This isn't picking on Ampeg by any means. AFAIK Barefaced is the only manufacturer that provides that critical bit of information.

A rig of that sort will only sound as good as the crossover allows it to. That means having sufficient high pass slope to prevent over-excursion of the midranges. It also means low passing the woofer cab, otherwise the woofers and midranges will fight each other where they're operating in the same frequencies. MIdrange drivers are a good idea, but as is the case with all good ideas it's the execution that determines success versus failure. If the bright box doesn't have a jack to send a low passed signal to the woofer cab the execution was flawed. If they didn't do that then the high pass filter, if it has one, is also likely to be inadequate.

Probably, but thermal power capacity has no relationship with maximum SPL. A 100w driver with 5mm xmax will go 3dB louder than a 200w driver with 3.5mm xmax.

Without xmax you can't calculate maximum SPL.

3dB higher sensitivity from the fifteens, which is easy to come by, makes 200 watts the equivalent of 400 watts into tens. Of course not all fifteens will have 3dB higher than all tens, but most will. Going to a pair of 210s would likely be competitive with a pair of 115, but that's not one of the options he mentioned.

Decibels is a matter of speaker sensitivity and frequency response. On average fifteens have higher sensitivity and lower frequency response than tens, so on average two fifteens will go louder and lower than two tens, even when driven with less power.

Since it's loaded with Eminence OEM probably built on the Alpha 10 chassis 95dB is a reasonable expectation. So is a high Fs and short xmax.

Not any American I know. 😉

It's also harder to mess up parallel. That's the only reason I can think of for Ampeg using 32 ohm drivers in the 810 SVT.