4fb7d882b2
The language files for the SVOX Pico engine result in the output of the synthesizer to be too soft, and barely audible on a phone speaker. The change implements a low shelf filter on the output of the synthesis and a drastic amplification. This works as intended because the synthesized data contains too much energy in the lower frequencies that is wasted on a phone speaker. Once filtered out, they leave room for amplication to address the volume issue.