I've read about the benefits of adding a sub for music (not really interested in home theatre tbh) but up until recently had been skeptical. However, I know they can be small and discreet and still make quite a difference. What are people's thoughts bearing in mind I have an amp with no sub out (but it does have 2 pairs of speaker binding posts)? Thinking about something like Rel t5i (budget £350 ish).