What is a Real Time Analyzer?
Back in the late 1970s audio engineers started using Real Time Analyzers, or RTAs, to provide a live display showing the frequency spectrum of audio signals. These early analyzers worked by using a collection of electronic bandpass filters. Each band was typically one-octave wide and the bands were distributed on center frequencies spaced in one-octave intervals. The most popular octave center frequencies are: 62.5 Hz, 125 Hz, 250 Hz, 500 Hz, 1 kHz, 2 kHz, 4 kHz, 8 kHz and 16 kHz. One full range audio signal was input to the bank of bandpass filters with the output of each filter representing the signal level for that frequency band. Then, the output of each filter would be fed into something equivalent to a VU meter, usually an LED display, to show the loudness of the signal in each frequency band. By placing the level displays side by side they formed a live graph of the audio signal and we were able to see the bass versus the treble energy, or perhaps a peak in the midrangeall in re
