I can't hear you

I’m in a bar and a woman (the waitress or owner?) asks me to turn down the volume on the sound system. There is something on tv and a radio playing. There is no knob to turn, just two buttons side by side on the front of the bar. I push a button to lower the volume. Awhile later, someone asks me to turn it down again. I hold down the button again, but the volume doesn’t go down. The guys at the bar are getting angry. I realize that you have to press the button repeatedly and not just hold it down.