[Adam Portrais]

Ok, this is going to sound like I'm retarded, but then again... Anyway, Let's say I have a reciver that pumps out 100W per channel. Now, would a speaker that is X inches big and handles 100W be any louder (dB wise) if X was bigger?

[Jason GT]

Size is not absolutely correlated with max speaker output.

Given certain input power, the SPL delivered depends on a speaker's efficiency which is a combination of many factors, such as driver type and design, speaker enclosure design etc.

You will be able to find bookshelf speakers which have greater efficiency (and thus spl output for given input power) than larger towers.

[Adam Portrais]

Ok here's the deal. A friend of mine (God love him) is trying to get into the world of DD and DTS. Being formally in a band he has speakers from his PA systems and whatnot. Now these are prtty big speakers (don't know their specs) that sound great with just stero sound. He wants to get a reciver but is not quite sure what to get (he, like me, is a student with a small budget). Would he need to get an amplifier to boost his signal or could he even use the amp he has for the PA ststem to boost it (remember he lives in an apartment). I have no idea if what I'm saying makes any sence at all but if anyone could help me help him, that would be great. Thanks.

[Chu Gai]

Let me get this straight...

1) You've got speakers that are used in a PA system because your friend used to play in a band. This I'm assuming is a system where the guitar is 'miked' and the mic feeds an amp that drives some speakers. Maybe some sort of cabinets that are either horns or something like JBL cabs.

2) Maybe it's not like in 1) but instead he's got a speaker cab that he used to run off his guitar amp.

3) Money being tight, you want to minimize the amount you spend on speakers, even not buy them at all and instead just buy a receiver. After all, if you're a student, money is better spent on beer/pizza/women...not necessarily in that order. Of course somewhere in all that you're studying!

4) You want to use those speakers and just buy a receiver and make do with things for the time being.

Can you do it is the question?

Sure. However...likely those speakers aren't 'full range', meaning they don't have spec's something like 30-19 kHz +/-2.5 dB. Is this terrible? Hell you're college students and if money's tight, I'd sure as heck let it slide until you graduate, get decent jobs, save your money, and buy something better suited.

What you need to do is find out the following:
speaker efficiency
their impedance (8, 6 ohms or whatever)
maximum power handling

Look it won't be perfect but might not be all that bad.