Wording tweaks

[rrlapointe]

• Change "Output" to "Speakers" in page 1 header; resolves Page 1 header says "Output option" when the group is labeled Speakers not Outputs #1
• Add dances to "great for" for large speakers and subwoofers; resolves Add dances to the "great for" for large speakers and subs #2
• Remove concerts from "great for" for subwoofers because bands are already mentioned separately and other kinds of concerts, e.g. concert band concerts, don't need subwoofers.