My LM3915 Sound Level Indicator project has a peak detector and in the DOT mode it shows ONE lighted LED bouncing around.
The datasheet says that oscillation or excessive noise causes a few LEDs to light in the DOT mode (from using a breadboard?).
Hint, hint: don't use a breadboard.
I made my project on a stripboard with all strips cut to be fairly short so they do not pickup interference. Its enclosure is plastic, not metal.
My circuit has extra gain and an AGC circuit so that it has a lot of gain when the levels are low then it reduces the gain when the levels are high. It shows a pin dropped on the floor in the next room and also shows very loud sounds.