Although high fidelity audio has made great progress in the past few decades, many modern stereo devices still fail to catch up with some old analog instruments common on amplifiers and receivers in the 1960s and 1980s. Things like Vu meters are no longer common, but they can be rebuilt into your sound system with the help of some microcontrollers. [mark] showed us how to reuse some old-fashioned features with this dual audio visualizer display.
The architecture not only includes two displays, but also the microcontroller tracks 170 channels in real time to drive the display. What is more impressive is that all this was done in the short version 4.1. To help manage all the data and keep it as fast as possible, it uses external RAM welded to the board and a second teensy audio board for real-time FFT analysis. Most channels are sent to the display where the spectrum analyzer is located, but two channels are reserved for the left and right stereo Vu meters on the second display.
Mark’s project was originally based on diylab software, so everything is open source. Although it was originally built for a specific hardware, mark set it up as a line input and line output plus a microphone input, so it can now be used for almost any audio hardware. For another version of the classic Vu meter, please take a look at this design based on arudino.