I will leave the BV question to someone else here that knows more about the actual heads.
As for getting into the menu, open the door and push the button (usually red, sometimes black) on the board door. This will take you into the menu options. After you enter, each time you push the button, it will take you to the next option. Sounds are usually the first few and you can adjust the levels with the Max Bet and Spin buttons. Off the top of my head, Spin will play a test sound at the current set volume. There will be a number on the credit display that reflects your volume level. I believe it is the Max Bet button that will increase it by one on whichever column you are on (it will be blinking). To change the column (from ones, to tens, to 100s, etc..), turn the reset key one time. Then the next column will be blinking and ready for adjustment. Personally, I keep my machines on 5 volume at home for standard spins, and 15 for bonus, and 30 for jackpots. But I live in a house where noise travels easily, so you may want it louder.
Anyway, you can make a lot of different adjustments for the machine in the options menu, depending on how many times you push the button on the door. Most adjustments are made using the Spin, Max Bet, and reset key.
Hopefully that is not too confusing...