These were my own design in audio level meters. This prototype was built to test in my next prototype audio controller. This design uses the LM3916N Dot/Bar display driver chip, and measures line-level audio signals. I got the 10-segment LED bargraph displays from RadioShack. These work GREAT on line-level audio signals and are very fluid and responsive, allowing both dot and bar modes.
This design could easily use the LM3914, LM3915 or LM3916 depending on the signal you’re measuring. This version uses a buffered input with a diode that rectifies the audio input to stabilize the display. Eventually I will redraw the original schematic and post it here.