musicrocks,

the reverb knob will be similar to the reverb found on many guitar amps. (i am presuming this is a keyboard amp) so (depending on the inputs) it should provide reverb on vocals if u plug in a mic.

with the computer, (on windows) go into
volume control
and make sure the input you are using isnt muted. this will let you hear whatever the mic is picking up. or you can turn this down or mute it and tell the computer to let you monitor what is being recorded. to do this, (in volume control) go Options>Properties and select "adjust volume for Recording" from the dropdown box. then make sure you have the proper level for your mic. But BEWARE FEEDBACK. you mentioned speakers so this is an issue if you turn either of them too loud.

The major problem with this is LATENCY. This is the delay caused by the audio running through the computer (therefore being converted and then converted back). The audio coming from the speakers (you should use headphones though) will be a little delayed. depending on your sound card this may or may not be acceptable

twon

Yes thanx man! i figured it out ..its a little diff on my computer options and is the reverb on the amp gonna be like cheap bad reverb? and also the quality of the sound is really bad is there any way of enhancing the quality just from comp options?

reverb is extremely taxing on a computer, and unless you have the appropriate hardware/software, it will probably sound horrible. make sure you experiement first.