miero

In that case the low-pass filter is sensitive to samples with a high amplitude (or near the clip). It is interesting that for -V0 low-pass filter was completely disabled. BTW, I was reencoding samples in the NPR listening test and from the spectrogram it seems that the clipped or nearly-clipped samples show bad behaviour due to improper lowpass filter also on 128kbps bitrate. The filter is just configure for a lower frequency there. More: http://mr.ieero.com/pub/npr-aq-test/ (ignore -in_test.png...

LAME3.99.5: ugly clip around 20kHz on CBR 320kbps (-1.5dBFS)