I am recording with the SL1. Why am I hearing noise in the background? I'm recording straight through scratch live by hooking the rca to my master output and the 1/4" mono jack I hook it up to the mic input of the SL1. My amp rca's are plugged in the record output...lol The reason why because they are homemade and want work in the master.

This is not a proper way of recording your mixes will the SL1. You are going to possibly fry the SL1 unit by doing this.

To properly record when using the SL1 see here: www.youtube.com

On my laptop I only have a mic input and headphone input. They say not to use the mic input. So what should I do to record with audacity.

You'll need to buy another external soundcard then, or upgrade (i.e. buy) to the SL3 to be able to record right in Scratch Live.

Could I use a cd recorder or a flash usb drive?

If the CD recorder is external then yes you should be able to run an output of your mixer into it and burn to a disk live.

The flash disk will serve no purpose.

ok