This circuit uses two quad op-amps to form an eight LED audio level meter. The op-amp used in this particular circuit is the LM324. It is a popular IC and should be available from many parts stores.

With a calibration DVD and sound level meter in hand, you can play a test pattern and set levels for your speakers. It also is a good idea to set all treble and bass controls to 0 as well. Set your ...

One of the coolest things any sound system can have is some kind of musical visualization. Thumping level meters that pump with the volume are a great example, and were particularly popular in the ...