A) what is a compressor pedal or what not. Ive heard almost evryone uses them, that do they do? What kind should i get? B) Line6 DL4 or BOSS RC-20 which one should i get? can boss do delay or just loops. What would you recommend besides these too? C) V-Bass? is it good. Im not planning on getting it but i was wondering if it was any good because i've heard that midi bass tracking is uber delayed.