Bill Fitzmaurice

Yeah, but how many bass amps have bridge mode? I suppose some do, but still that's very much a PA thing.

That's correct. It's not how Tony Hofmann wrote it down, but that's the gist of it. Why his last name ended up getting another 'F' with respect to his law no one seems to know.

7 hours ago, BassAdder27 said:

It makes an interesting read Bill … so perhaps smaller box with more efficient higher powered cones can produce more bass.

There's very little difference in the sensitivity of different bass drivers, so that's not going to work. Higher power handling to get more bass out of a smaller cabinet is a requisite, but the thermal ratings aren't what matter, mechanical ratings are. You can't get those unless you have the driver data sheets.

If you really don't want to get high output in the lows use a sealed cab. Even when the same size as a ported cab they give up almost an octave of low frequency extension.

Look at it this way. Violins don't go as loud as violas, which don't go as low as cellos, which don't go as low as double basses. Size is the reason why. The same physics apply to speaker cabinets.

How they're wired should be in the owners manuals. If they're not wired +1-1 I can't say why. For that matter I'd expect they'd use 2 pole Speakons, so that would be the only option.

If it's a mono signal the +1-1 poles should be used on the amp output and speaker input. There are special circumstances where both the +1-1 and +2-2 poles might be employed, but you'd seldom see them utilized on a bass amp and speaker. It's fairly common with PA, using a dual channel amp and bi-amped speaker. The low frequency output of the amp and low frequency input of the speaker would go to the +1-1 poles, the highs to the +2-2 poles. Using a standard wired 4 pole 4 conductor cable it would be plugged into either amp channel output jack and into either input jack on the speaker, if it has two, and always be right.  Many's the HF horn that was blown using 1/4" plugging the LF output into the HF input.

Search 'Hoffman's Iron Law'. If you're going to go small and low you it requires a lot of power, and drivers that can take it, both thermally and mechanically.

Speakons should not have a direction. There are amps and cabs that aren't wired as they should be, forcing that arrangement. Odd how even some engineers don't know how to read applications charts. Frustrating to say the least, but c'est la vie.

At low volume you're probably OK. It depends on the amp. Old Fenders would take anything you threw at them and kept coming back for more.

21 hours ago, nilebodgers said:

I used orange 2 core mains cable back in the day. No chance of mistaking that for a signal cable.

Black and Decker? There's a famous incident about Peter Walker showing up at an introduction of his latest Quad speaker without any cables. He went to the nearest hardware store and bought a couple of Black and Decker mains cords, cut the ends off, and put them in play. The audio press were impressed by the speakers, but some attributed the excellence of the sound to those orange cables of unknown origin. 🙄

Using only two poles of a four pole Speakon is common. You see it more in PA, but sometimes in amps. What's more common is two pole Speakon jacks on amps and speakers, used with four pole/four wire Speakon cables. You can use four pole cables with either two or four pole jacks, so if all the cables you carry are four pole you're not digging through the cable bin looking for a two pole cable.

1 hour ago, Beer of the Bass said:

 

Most valve amps are unlikely to have any problem with a 3 ohm load on the 4 ohm tap but you could always check in with the maker to see what they think of the idea.

They would have no problem with a 3 ohm load. They'd not be pleased with a 7 ohm load, but that's what the 8 ohm tap is for. The impedance rating for SS amps is the minimum you may use, with valves it's the maximum.

23 hours ago, Woodinblack said:

 

But not keen on an open output, who is to say how it would melt.

When the insulation in the cable melts the usual result is a short circuit. For an open circuit to occur the conductor would have to melt. That could happen, but long before the conductor melts it would create enough heat to melt the insulation and likely cause a short circuit. I've never seen an instrument cable used as a speaker cable suffer a melted conductor, but I've seen plenty with melted insulation. It's all Leo Fender's fault, for using the same jack for inputs and speaker outputs, because that was the less expensive option.

There are 115/410 combinations that would work well, as in a bi-amped rig with a long throw sub-driver 115 and a 410 loaded with guitar tens, but that's not what you see being used. Even that would be far from ideal, as it doesn't take four tens to match up well with one fifteen. One or two would be sufficient.

2 hours ago, BassAdder27 said:

If this was a valve amp it would now be toast so think yourself very lucky !!

A valve amp is unaffected by a shorted output. For that matter Fender valve amps use a switched speaker jack that shorts the output so that the amp won't be damaged by what will hurt it, which is no load. That's why they don't work when you inadvertently plug in to the extension speaker jack rather than the speaker jack. SS amps that lack short circuit protection circuitry, which are rare, can blow output devices and more with a shorted output cable.

5 hours ago, Phil Starr said:

 If the tweeter is out of circuit anyway it will have no effect on impedance.

Actually it does. With no load on the high pass filter it can exhibit a very low impedance within its pass band, which can create problems. The safe way to remove a tweeter circuit is to disconnect the crossover entirely, wiring the woofers direct to the input jacks.

Since it was open back it was worthless for bass above bedroom or low studio levels. It was designated as Fender's bass amp only because it was the largest they made that year.  The Concert guitar amp was essentially the same amp with tremolo, built on a newer chassis.

2 hours ago, Newfoundfreedom said:

 

What five pages? You're the third post. 

https://www.talkbass.com/threads/2x12-vs-two-1x12-cabs-pros-and-cons.1319015/

Assuming the same drivers, the same total internal volume, and the same port tuning in the case of a ported cab, this is a case where 1+1=2, pure and simple. What discussion on this simple concept could possibly take five pages I can't imagine, and life's too short for me to bother finding out. Arguing about minutiae ad infinitum is why I left Talkbass ten years ago.

The meaning of warmth isn't too difficult to imagine. The same for boom, or harsh. But when you get into the terms used by oddiophiles it's easy to be left in head scratching mode. I have no idea what they mean by 'air', other than that they have far too much of it between their ears. And of course there's 'fast bass'. WTF?? Did the bass player finish the song three bars before the rest of the band? 🙄

For most warmth is considered as a strong midrange with not a lot of low end, which is what I'd expect from his current arrangement.

1 hour ago, Downunderwonder said:

2nd cab everyday except Sunday, when you get the band to quiet down.

Not in a Southern Baptist church service. The scene with James Brown as the pastor in 'The Blues Brothers' was pretty accurate. https://www.youtube.com/watch?v=PZpH9Khn0E0

6 hours ago, lownote said:

 Now, should I get a more powerful head (eg 600) so I get more headroom with one cab I've got.  

Chances are you've reached what your cab is capable of putting out with your current amp.

Quote

should I get a second cab to pull a tad more power out of the head I have and double the number of oomph makers?

Power doesn't matter. What does matter is driver displacement and speaker sensitivity. The 6dB increase in voltage sensitivity from adding a second identical cab and the 6dB increase in maximum displacement limited output are the equivalent of quadrupling power if your 210 could handle it, the possibility of which is slim to none, and Slim just left town.

Two would give slightly less low end than one and the midbass would boom.

The BL12-200x are about as flat as you're going to get in that enclosure. What you call very warm I'd call a weak low end, as its response is -10dB at 55Hz. That's not the fault of the drivers, it's what you're going to get from a sealed enclosure that small. If what you're after is stronger lows you've got to go larger. If I had to use that enclosure I'd load it with one Eminence BP122. It would be -10dB at 36Hz, and one BP122 in that enclosure would be capable of more output than two BL12-200x.

The last matched head and cab I owned was a '65 Fender Bassman, which I bought new. That's how long it's been since matching was relevant, and back then it was hard to find separates sold as new anyway.