Hey... I want to hook up 2 different speakers to an amp. The old speakers were rated at 4 ohms, and the new speakers are rated at 8 ohms. I hear people saying that this might draw too much power from the amp and blow it up. Is this true? And do ohms affect how the speakers sound?

Give this site a shot http://www.rexc.com/services/ohms.htm

If you hook up a 4 ohm and an 8 ohm speaker in parrellel, that will be 3 oms. That might be a little low, most amps can handle a 4 ohm load but don't recommend going below that. Some can handle as low as a 2 ohm load but you should check your amplifier specs to see what it can handle. Now if you hook them in series, it will be 12 ohms and that would be fine but it won't be quite as loud. "do ohms affect how the speakers sound"? Not directly but the general rule of thumb is the lower the impedance, the louder the speaker.

If you hook up a 4ohm set and an 8ohm set that triples the current that a single 8ohm set would draw, and will quite possibly blow your amp. http://www.carvin.com/doctorsound/

Unbelieveable! Lets set the record straight. I believe what you have in mind is just changing from one set of speakers (4 ohm) to a different set (8 ohm). This will not harm the amp, but they will never go as loud as the originals unless they are low compliance types (which you would not want anyway) because of the increased impedance. The only effect you might run into would be a muddying of low frequencies in a high power system using capacitive output coupling where the caps are carefully selected for a particular speaker impedance. If you have any other connection scheme in mind, we would need a description to evaluate the final effect.