Bill Fitzmaurice

The BN10-200X is displacement limited to 120 watts, so a 500w/8 ohm amp would have no problem driving four of them to maximum output. If you can't find one rated for 2 ohms rewire them to series/parallel for 8 ohms. BTW, you didn't bi-amp if you didn't have an electronic crossover. You were dual amping.

You might not need as much power as you think, nor dual heads. I may be able to confirm it knowing what drivers you have.

Actually it's small, low and sensitive. Money does enter the equation, as longer xmax drivers capable of going low in small boxes tend to be more expensive, but they still can't get around the sensitivity, so to go loud requires more power, which means a more expensive amp as well.

That has nothing to do with the magnet material. A higher Fs and other factors give the BN300S higher sensitivity in the mids, but also result in less low frequency extension. One of the highest sensitivity drivers ever made was JBL D130, which had an AlNico magnet. It also had very poor low frequency response, but that was an acceptable trade off in 1948, when 25 watt amps were state of the art. It was also designed some 17 years before the advent the Thiele/Small specs. Only after that did designers realize that the main way to get higher sensitivity, more magnetic flux, doesn't increase sensitivity linearly across the full audio spectrum. It tilts it to the mids and highs. Where electric bass is concerned you want to compare sensitivity where it matters most, 50 to 80Hz. You can't do that with manufacturer data sheet charts, as they are measured with the driver mounted in a wall, and don't show the results in an enclosure. You need to use speaker modeling software to do that.

Chances are you can't find one, not that it matters. Cab ratings are thermal, and next to meaningless. What matters is the mechanical displacement, how much air the driver cones can move without creating high distortion or suffering physical damage. You can find out the displacement if you know what drivers are being used and have their Thiele/Small specs, but cab manufacturers are loathe to reveal that. Barefaced does, with good reason. They boast as much displacement as anyone, more than most. It's the main reason why they're held in such high regard. https://barefacedaudio.com/pages/how-speakers-move-air-volume-displacement

K12H-200TC If the xmax spec is 2mm they have more headroom than most guitar drivers, the Greenback is 0.7mm, but the rest of the specs if similar to the K12H-200TC aren't well suited to guitar. I'd be very wary, as even the BN-12 300S has only 2.5mm xmax.

My concern about the K12T-200 is xmax. I can't find specs on it, but the K12H-200TC xmax is only 2mm. That's half what I'd consider the minimum acceptable. It results in a real world mechanical power limit of 25 watts. One can only speculate if the K12T-200 xmax is that short, but given the age of it and knowing Celestion came very late to the party where real bass specific drivers are concerned I wouldn't want to assume otherwise.

IMHO those who have that attitude have no idea what a 'pure' tone is and would be shocked to see the measured response of their rig. No component has flat response, starting with the bass, ending with the room where it's being played. If tone controls weren't meant to be used they wouldn't be there.

Maybe it does, maybe it doesn't, but since the speaker doesn't have flat response it just doesn't matter. The amp probably has an EQ pre-shape as well, most do. Where EQ is concerned set it where it sounds best via trial and error. When it sounds good it is good.

The 2x8 ohm will be 6dB louder than 1x8 ohm. That's from the combination of 3dB additional sensitivity from the halving of impedance and 3dB additional sensitivity from the doubling of cone area. It will also have 6dB more maximum output, as the Vd (displacement) is doubled. That makes it 3dB louder at the same volume setting as the 1x4 ohm, and 6dB higher maximum output than the 1x4 ohm. There's a saying in automobile circles that there's no replacement for displacement. It applies to speakers as well, because loudspeaker cones are pistons.

The 4 ohm will be 3dB louder, as the cone of the 4 ohm driver moves further with the same applied voltage. However, where maximum output is concerned they're the same, as both have the same maximum excursion. It just takes more voltage into the 8 ohm to get there, which takes only a slight increase of the volume knob, say from 5 to 6. Not from 5 to 10.

He has a point. If one driver is sufficient to provide all you need, or ever expect to need, for output then 4 ohms has its advantages where the amp voltage headroom is concerned. But 4 ohm tens and twelves are rare, because 2x cabs are far more common, and manufacturers aren't going to make many 4 ohm drivers when most of the demand is for 8 ohms. The exception is fifteens, which are more commonly offered in 4 ohms because most fifteen users only need one.

I quit going there before they could kick me off. Maybe it's different now, but ten years ago it was one of the worst moderated forums I've ever come across. IMO anything that can't be said in a paragraph using non-technical language is a waste of time for all involved. KISS isn't just the name of a band. 😉

It will, but it has nothing to do with power, everything to do with voltage. The amp puts out the same voltage into any load. (A good thing that is, because the actual impedance isn't a constant, it varies with frequency, so if this wasn't the case every frequency would be at a different level.) If all else other than impedance is equal, which it never is, with the same voltage applied the cone of the 4 ohm driver will move further than the cone of the 8 ohm driver. This results in a 3dB increase in output. There can be tone differences as well, because all else isn't equal, including but not limited to inductance and moving mass. As for the perceived increase in dynamics at high levels, that's also voltage related. An amp's dynamic response suffers when it's pushed close to its voltage output limit. Using a lower impedance driver gives more voltage headroom from the amp, which gives better dynamic response. This begs the question 'why not always use low impedance drivers?'. The answer is that the lower the impedance the higher the current draw, which can create its own set of problems.

Not your fault, industry fault. What makes speakers go louder is increasing the voltage output of the amp. Watts never should have been used to define amplifier output, or speaker capacity. But they were, and now we're stuck with it.

Yes, with a valve amp, so that the output valves can be pushed into hard clipping while keeping the voltage to the speakers low so that they're not too loud and not overpowered. Tom Scholz sold one, and I believe Marshall did as well. Useful as that is on guitar it's not what I'd want to use with electric bass.

There's no point. Power and decibels output are only indirectly related. It's called a power soak. Using one is akin to driving with your parking brake engaged so that you can get all the horsepower out of your engine. 🙄

Is that a reference to the women? Or the livestock? 😁 On our side of the pond they had to remove the grass and install artificial turf on the University of Vermont football field, to stop the cheerleaders from grazing during halftime. 🙄

I managed to get a decent level from my Bassman, when I played it through eight twelves. 😳 This was the 60s, when the average twelve had only 1mm xmax. Today it's not hard to find a 212 that has 450cc displacement. The 212 Bassman/Bandmaster/Twin Reverb loaded with Jensen C12s had 80cc. They also had Fs of 112Hz, so going low wasn't in their wheelhouse.

It's the same cab as the 50w Bassman, so it's marginal. The drivers aren't bass specific, they're generic musical instrument drivers. They sound OK at low levels, but that's about it. A Twin is OK for recording, again at low levels. Carol Kaye, possibly the most recorded bassist of all time, mainly used a Fender Concert 410 in the 60s-70s. . If you've heard the Beach Boys you've heard that amp.

True. I mentioned the concept to Alex way back before he started his company, it's called a 1.5 alignment, and he eventually employed it. It's not just to prevent comb filtering in the highs, it also improves horizontal dispersion in the mids. But a pair of 2x10 vertically stacked also has the advantage of getting drivers up higher so you can hear the mids better when close to the cab.

Not that I recommend it, but if you connect the terminals of a 9V battery, the small type, with a screw driver you'll get a small spark. Do so with a 12v car battery and the screw driver will suffer serious damage. It can even get arc welded to the terminals. The difference is due to the ampere capacity of the two. Consider a taser. They run at 30 to 50k volts. They tend to be non-lethal because they have very low ampere capacity. A static shock you receive on a dry winter day can be an upwards of 75,000 volts, but the current is so small that all you might feel is a slight annoying zap. Like most electricians I seldom bothered to turn off the breaker to swap out an outlet or switch, and as a result got zapped dozens of times over the years. Smart? Maybe not, but that's what we do. I once stuck my finger in the wrong place in a Fender Bassman and got the full 470v. Unpleasant, but not injurious. Still, that experience educated me to the value of using a bleeder resistor to drain the caps before messing around. 😳

Leave it on the road case. Whether you go with a second Midget or some other cab with multiple drivers you want them vertical, not horizontal. It sounds better that way, to you and to the audience.

Not necessarily lethal, and it's not the voltage that kills, it's the amperes. Still, getting zapped with even 450v isn't a pleasant experience. One thing to do is to turn the power and standby switches on, with the amp unplugged, before removing the chassis from the case, especially the standby. When the standby switch is off the power supply caps will hold their voltage for a long time. With it on they'll discharge, albeit slowly.

Clean everything with contact cleaner, including the pots, tube sockets and tube pins.