I'll try to answer a couple of your questions. Yes, it is an mk6 machine. If you have the barrel key that goes into the Meter/Audit switch on the right side of the Cabinet, that can be used to change the sound level overall on the machine. The handpay over $1199.99 is set in the jurisdiction for the machine. Changing settings like this require a set/clear chip set, and are a bit tricky to do. I would recommend that you leave the settings that need the set/clear chip alone until you become much more familiar with the machine. To change the sound volume, turn the machine on, then turn the meter/audit key to audit. An operator mode menu will appear. Click the service button to move the cursor down to option 5 Operator Setup/ Selections. Then push the play 4 Reels button, which takes you to a sub menu. Click the service button to highlight 5.6 Sound System Setup. Press the play 5 Reels button again, and a red bar indicating sound volume will appear. Pressing the service button will increse sound level, cashout/take win will decrease it. Other options on this page can be used. When finished turn the meter/audit key to the original position. You may have to shut off and restart the machine to hear the final sound level.