This might not qualify as advertising but another thing that helped my business was to STUDY the local market via independent area newspapers and memorize the names of bands and players. Then I hit the clubs, cards in pocket and did the serious networking. After 2 or 3 times they get to know you and know your serious about your craft. Only now (3 years later) is it all starting to pay off. I also hit up all the large non profits arts orgs, Let them know what my services were and weasled my way into what I call "the club". These folks control all kinds of projects and money. And if you provide great service you get ALL their work. This may sound stupid but i think of it like this...
Say a musician is expecting a package from UPS and it's a day late.
He calls CS and gets treated like GOLD.. they drop the shipping charges and it arrives the next day. Then he calls your studio, gets the answering machine and has to wait 2 days for a call back. My point is our competition is ANY business that has customers, Including the largest businesses on the planet. NOT just other local audio service companies.
Our goal should be to NEVER have an unsatisfied customer...NEVER....
Do WHATEVER it takes for people to leave happy. Remember for alot of people this is their discrectionary income. They record instead of going on vacation. Thrill them...Make it fun!
These folks WILL go out and sing your praises. After a while it'll start to steamroll
Good luck!