Speaker dominance with combo + ext cab?

[jordan]

I've been considering adding a 1x12 extension cab to my 1x12 Rivera R55 amp. At the moment my Rivera has a Celestion GT-85T, but I'm about to swap that out with a Celestion Vintage Century, and possibly put the GT-85T in a seperate 1x12 cab.

So here's the question:
When running the rivera through it's own speaker AND a 1x12 cabinet, are both speakers being used equally? i.e. is one speaker more dominant than the other, or being driven harder?

I'm not sure if that's a stupid question or not(!). I'm going to put the Vintage Century in the combo itself as it's the better speaker, and I'll still regularly use the combo without the extension cab.

Also, would you guys suggest open-back or closed-back for the extension cab? I'm looking to get one of the Pilot cabs from award-session.com if that's any use.

Cheers,
Jordan.

[mikeluke]

I think that the answer is "it depends" - ideally you would want to match speaker power handling as well as impedance.  e.g. you would want two speakers rated at 60W, rather than one 60W and one 75W. Although if your amp only kicked out (e.g) 20W the difference in 'drive' would be marginal.  Using something like a 30W and a 75W rated speaker would result in the 30W being driven more than the 75W.

I think..... (he says, preparing for a kicking from the technophiles out there...)

[Johnny Mac]

You could make one as a project. (just read your blog on your Strat) I had a book of T Drawings that Celestion published. Not sure if I still have it but there should be on the web now i would have thought.

[Kilby]

Speaker efficency would also make a difference.

There are 30 watt speakers which are considerably louder than other, plus frequency response could also cause a perceived difference in volume.

Rob...