The Youtube Brad P clip sounds, are supernice. However, I doubt it that you can get those right out of the can. What you're hearing on that track is not just an amp with a sm57 in front of it, but

1) the result of great playing,
2) good recording technique (with perhaps a royer ribbon close and a room mic a couple of feet away).
3) Great mixing skills, carefully compressing and eq'ing instruments to gel in with each other
4) best in class mastering technique

After writing the above, I did a simple google search (!) and found this link: http://www.musicradar.com/guitarist/brad-paisleys-gear-267937

Effects: Compressor + Tubescreamer + slap delays

Speakers:
These are 2 x 12 cabinets, with one [Celestion] Blue and one Gold. Two Blues can give you a little bit much in the low end when they break up, so one Blue and one Gold solves that."


Mic: Royer

Hi
Definitely Celestion Gold! Sounds awesome and records great as well.
Also one easy mod which would have tremendous effect on the tone you need –
Get three way mini toggle switch, solder 47pf cap on one filament and 100pf on another.
Solder together their outer contacts and connect it to MASTER volume’s right filament.
From the toggle switch central contact connect wire to master’s central filament.
In the middle position your amp’s tone would be intact and up or down positions would give you desired top end.
This is not a country picking but tone is similar with strat bridge pickup and Celestion gold speaker miced slightly off axis.
http://www.guitarampcab.com/bbfnk.mp3
Cheers

Power wise they will be fine in parallel or series.
I always prefer tone when I use speakers in parallel, always more open and punchy.
Weber and Celeston alnico 10’’s  would sound great I think.
16 ohm and 15 ohm in paralel = 7,5 ohm

also be aware that diff brands of speakers don't have identical impedance at all frequencies

I tried a Celestion Gold in parallel with a Fane AXA12 that was 1dB more sensitive, and the Gold was twice as loud - hence it must have been drawing much more from the amp.
If you have a 50w amp and a 30w and a 50w driver in parallel, check which runs the loudest (& take into account the sensitivities), you may put 40w into one driver without realising

You're a little confrontational sounding really. Please try to be a bit less blunt.

I have a Celestion Gold 8 ohm
and a
Fane AXA12 8 ohm

I ordered them specifically, and bought them new, and that's what is says on them.

Do you believe that all voice coils in all speakers of the same nominal impedance have the same characteristics?
The impedance is not even consistent across the frequency range in a single driver.

see http://www.installer.com/tech/sit.html

cheers
Tone

I would agree that speakers would usually change with use. I assume it's mostly the cone rather than the voice coil and magnetic characteristics

These were both new, it was the volume difference that startled me, since the Fane should be 1-2dB louder.
I got the Gold direct from Celestion, to replace a new one with nasty rasping on 2 notes, this replacement has quieter nasty rasping on one note, I am still not sure whether they all have these faults. But it sounds so good with my BM50. Any advice anyone?

So my point is that with 2 parallel different speakers - the interaction is way more complicated than it first appears, they can each steal power at different frequencies, as if they had some king of weird crossover filters, presumably hence Matchless cabs deploying a tested successful mismatch. But as well as that, you may drive one voice coil more than the other at some frequency, and if you are expecting an even split of power into max rating, you could be overloading one.

Cheers
Tone

hi guys

there are couple of points here

1. higher sensitivity means you get more dB per watt of power, so the AXA should be louder (case in point i use a g12-65 and EVM12 and the EV is definitely louder)
2. yes the speakers have dfferent characteristics...which in a dymanic sense (ie AC)means Inductance and Resistance and capacitance. every speaker has its own values and hence responds diffrently at any given power and frequency
3. mechanics: cones are made from different materials and and age differently and also interact with signals frequescy and power in different ways. hence the perceived difference in tone.
4. the physical design and shape of the cone and voice coil, and the gap between voice coil and magnet....
5. ageing: magnets do not age, however speaker cones will both with use and also good ole mother nature... and that also includes the breakin time for them....
6: and lastly dont forget the amp that drives it... the output trannie has its own set of characteristics and wll react differently to different complex inductive loads.

a speaker is a very simple electric motor in some ways ... if you think of it that way rather than just an inductor. they were never designed to be equal and thank god for that, imagine a world where all speakers were the same.... HOW BORING!!

mixing speakers is great fun... however its also a hit and miss affair....and also depends on your own personal tates.

btw: my weber had a rattle at one note when new and it settles after a week or two of hard playing.