A Question on Speaker Driver Efficiency


I have been tweaking my guitar amps, by upgrading the speakers.

I installed a larger speaker (was 8" now 10") in my bass amp, but I made sure it was very efficient - net result
- not only is the bass much deeper sounding,
- but because the new driver was more efficiant I now play at a lower volume.

So I am now considering upgrading my other amp (i.e. used for my 6 string) and got to thinking about building a new cabinet that houses two speakers.

I know that connecting the speakers in ...
- series will double the impedance, i.e. 2 x 4 ohms would have an onverall impedance of 8 ohms
- parallel will halve the impedance, i.e. 2 x 16 ohms would have an onverall impedance of 8 ohms

But what I have not been able to get my head around is...
- what will each connection method (i.e. series or parallel) have on the "combined" sensitivity rating?
- e.g. if both speakers are rated at 96db sensitivity, will the overall sensitivity change due to the connection method or remain at 96db?

Since I can get 4 ohm or 16 ohm drivers - which connection method would be best? series or parallel?

in case it is a factor
- the amp is 15 watts into 8 ohm
- I am looking at employing two identical drivers each rated at 96db sensitivity
- 96 db (or higher) is the target for the combined sensitivity

Any help is appreciated - Many Thanks Steve
williewonka

Showing 4 responses by ptss

@cj1965 and other Respected and Valued contributors to this forum. cj1965 is obviously well schooled in the math, a stickler for precision, and interested in the truth of the matter. I believe/hope his knowledge “could” become valued here. However, “manners” are vital in order to become a “respected and Valued” member of any reasonable group. “Anyone” can have a misstep or slip up. We’re human. Such an event “does not” necessarily diminish one’s value or credibility. I’ll mention Ralph here as he is known to produce exceptionally listenable and prized audio equipment under the ATMASPHERE label; and is without doubt a valued contributor. 
However, harsh criticism, or sarcasm, is “generally recognized” as a deliberate attempt to demean a person.
Reasonable and compassionate people will/may react to defend the person(s) subject to the personal attacks. 
This has occurred here. 
I don’t support a ban of the offender at this time. He may have been having a “bad day(s) for reasons unknown. I do believe apologies are “generally accepted”; and are a good response to a correction of a error in a “statements of fact”, even if semantics are causing the misunderstanding, as well as for “personal insults”. Unfortunately, insults are more unacceptable than factual errors(which can always be corrected!). Insults, even if based on accurate facts, cannot be corrected. They linger in the minds of all. I highly recommend the high road of, at the minimum, a general apology for insulting comments. And best wishes to all. Peter
Cj1965 has made mistakes. Just shows he’s no different than anyone else when it comes to knowledgeable discussion.
Here’s hoping he’s at least bright enough-from an EQ perspective- to realize he wouldn’t enjoy belittling, condescending, or harshly critical comments directed as a personal attack on him. If he is “bright” enough he will reflect on his “petty” attempts at personal disparagement and get on with his sincere apology. Man up. If he doesn’t apologize he’ll be remembered (forgotten) as an inconsiderate, tiny minded( as he just couldn’t see the big picture) cretin, who could do a bit of math-but not always correctly :(
I get particularly displeased when a person is graciously made aware of a shortcoming— but carries blithely on.
I was taught that’s a true true sign of real ignorance. 
Life is always interesting. Here again we have the one who is most insulting - to be the most sensitive... aw , darn shame ain’t it ...