28-07-2021, 05:46 PM
As has been said, the impedance varies wildly with frequency. But to get some perspective on this, take a look here: https://www.fane-international.com/image...071117.png
That is for a randomly selected 12" speaker that might well be used in this sort of application (Fane Sovereign 12-300).
This is a nominally 8 ohm speaker. But notice that the impedance varies between 7 and 90 ohms.
So the impedance "seen" by the amp depends on what notes you play!
Personally, I'd either repair the torn diaphragm or just run it with one working speaker (cut a sheet of ply or MDF to cover the opening left by the faulty speaker). A replacement speaker will likely have a very different "tone", which will change the sound of the amp, and not necessarily for the better (but that's impossible to predict without trying it, of course). And (hopefully) needless to say, the loss of output level resulting from only one speaker running will be pretty negligible anyway. And it'll be a bit easier to carry to gigs!
As a general point, it will sound better with only 1 speaker. By "better", I mean the sound won't change as much as you move about in front of it (because two speakers carrying the same signal will cause "lobing"). And on a stage, you'll have a mic in front of the cab to feed the PA - with two different speakers in the cab, you'll have to decide which one sounds best so you can instruct the sound engineer where to put his mic. And that engineer will be constantly on at you to turn it down anyway, which gets me back to my point above (just one working unit will be plenty). Trust me - after drummers (who don't have volume controls), a live engineer's worst nightmare is guitarists who won't turn down their backline. Frankly, in the local 300-seat venue where I've done a lot of work, even a 10W practice amp is too loud.
And if you're back on stage doing gigs, you'll have a foldback monitor pointing at you, and if you ask nicely, the engineer will put as much of your guitar as you ask for (as that's not contributing so much to what the audience hear, within reason). So there's no need for a loud guitar amp any more. A lot of the big cabs you see on a stage today are either not in use, or just empty "dummies" - all for visual effect. A lot of guitarists use modelling amps that go straight into the PA via a DI, with all of their on-stage sound coming from their foldback monitor. Things have changed a lot in the last few decades, and the result is a lot better for the audiences...
That is for a randomly selected 12" speaker that might well be used in this sort of application (Fane Sovereign 12-300).
This is a nominally 8 ohm speaker. But notice that the impedance varies between 7 and 90 ohms.
So the impedance "seen" by the amp depends on what notes you play!
Personally, I'd either repair the torn diaphragm or just run it with one working speaker (cut a sheet of ply or MDF to cover the opening left by the faulty speaker). A replacement speaker will likely have a very different "tone", which will change the sound of the amp, and not necessarily for the better (but that's impossible to predict without trying it, of course). And (hopefully) needless to say, the loss of output level resulting from only one speaker running will be pretty negligible anyway. And it'll be a bit easier to carry to gigs!
As a general point, it will sound better with only 1 speaker. By "better", I mean the sound won't change as much as you move about in front of it (because two speakers carrying the same signal will cause "lobing"). And on a stage, you'll have a mic in front of the cab to feed the PA - with two different speakers in the cab, you'll have to decide which one sounds best so you can instruct the sound engineer where to put his mic. And that engineer will be constantly on at you to turn it down anyway, which gets me back to my point above (just one working unit will be plenty). Trust me - after drummers (who don't have volume controls), a live engineer's worst nightmare is guitarists who won't turn down their backline. Frankly, in the local 300-seat venue where I've done a lot of work, even a 10W practice amp is too loud.
And if you're back on stage doing gigs, you'll have a foldback monitor pointing at you, and if you ask nicely, the engineer will put as much of your guitar as you ask for (as that's not contributing so much to what the audience hear, within reason). So there's no need for a loud guitar amp any more. A lot of the big cabs you see on a stage today are either not in use, or just empty "dummies" - all for visual effect. A lot of guitarists use modelling amps that go straight into the PA via a DI, with all of their on-stage sound coming from their foldback monitor. Things have changed a lot in the last few decades, and the result is a lot better for the audiences...
