#1
Well i want to build cab and have just finished reading through the cab tutorial. Lot of usefull info which has led me to my question about a 2x12 im thinking of build. In there they say if you series wire two speakers it doubles the impedence and vice versa if you wire it in parallel. Does this alter the wattage, say if it is two 150w speakers wired in series does that make it total of 75w,, and then for parrale would it make it total of 300w, (basically the opposite to what the impedence does.) or would it always be a total of 300w. The reason i ask is i want make a cab. I have a 75w combo amp with an 8ohm external speaker socket. I was wondering what would be the best speaker configuration for that size amp. i know i would probably need two 4ohm speakers wired in series but im not sure what wattage speakers i would need. In the tutorial they said if you have a small wattage amp driving a large speaker it can kill your amp, but if it is a large amp driving small speakers it would kill the speakers first. So what are my options? is it worth making a cab for this amp? or should i just stick to using it as a combo. all help would be greatly appreciated. Sorry its long to read and i hope i made sense.
#2
two speakers would dissipate half of the 75W each regardless of how you wire them(37.5W each).
#3
I'd go ahead and just put two 16 ohm speakers in parallel for that.
Personally, I'd just go for a 75 watt power rating, because who knows how you may want to use those speakers later...I like versatility in gear.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#4
So in the case of the 16ohm would i by two 16ohm at 75w each wired in parallel two give me one 8ohm 75w total? is that what DAN meant by the 37.5w. or would it be two 150w 16ohm wired in parralel to give me a total of 75w 8ohm.
#5
The watts all add regardless of wiring. two 100 watt speakers in series has a 200 watt max rating, while two 100 watt speakers in parallel also has a 100 watt rating.

So in your case, the lowest wattage you can use is 37.5 watts for each speaker, anything over that is fine.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#6
My 8 ohm outlet says it has a max wattage of 75w and the 4ohm has a max of 100w. Am i able to use two celestion 70/80 (i think there 75w) for the cab. Would these be to large? Also how does that theory of of big amp little speakers good, Little amp big speakers bad work. From what i could see marshall heads are about 100w. and usually the speakers are a higher wattage, so how do they get away without blowing something?
#7
The speakers should be rated higher than the amp...the problem is when the speakers are rated for a value lower than the amps output.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#8
So if i go the celestions would i be safer going for a 4ohm rating or an 8 ohm. Im not really trying to make it sound louder but more colourful, if that makes sense. maybe a better word is a fuller sound.
#9
They should sound almost identical. Whatever is more practical for you is the way to go.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#10
Cheers for all you help mate. Much appreciated. they may have been obvious questions but hey, if you dont ask, youll never know.