A volume unit (VU) meter or standard volume indicator (SVI) is a device displaying a representation of the signal level in audio equipment.

When using a VU meter, the audio system is calibrated with a sine wave tone at a "reference level" for the system. At the reference level, the VU meter shows "0" for a sine-wave tone, but the engineer must know that, with music or speech, to always infer that peak levels are always between 6 dB and 10 dB higher than the reference level. The usefulness of the VU meter comes from the fact that for most types of audio sources the system engineer can count on these peaks being within this range and can design the audio system with confidence. Good engineering practice is to always build in a little extra "headroom", as it is called, to cover the strange conditions where an audio signal might exceed normal peak levels or the equipment operator fails to adjust the levels correctly. 

In this design we have used KA2281 IC to make VU Meter, it requires very less components as well, and easily available in the market. it works in 2 channels.

Complete DIY Video Available at - https://www.youtube.com/watch?v=dNPufHT2vDU&t=137s

DESIGNED BY INDIAN XTREME AUDIO