Click for a larger version! The spectrogram comparison. How to read it: left top, the voiceover by itself. Left bottom: The music by itself. Now observe the difference between Right top (the two tracks separated by unmodified headphones) and the Right Bottom (both tracks separated by the modified headphones) – it’s clearly visible how much of the bleeding outside music track has been cut out of the sound operator’s hearing. [On-Set Audio Monitoring: How to make $30 DIY Passive Noise Canceling Headphones]

Click for a larger version! The spectrogram comparison. How to read it: left top, the voiceover by itself. Left bottom: The music by itself. Now observe the difference between Right top (the two tracks separated by unmodified headphones) and the Right Bottom (both tracks separated by the modified headphones) - it's clearly visible how much of the bleeding outside music track has been cut out of the sound operator's hearing.

Click for a larger version! The spectrogram comparison. How to read it: left top, the voiceover by itself. Left bottom: The music by itself. Now observe the difference between Right top (the two tracks separated by unmodified headphones) and the Right Bottom (both tracks separated by the modified headphones) – it’s clearly visible how much of the bleeding outside music track has been cut out of the sound operator’s hearing.