Expand frequency range to 30khz or 40khz

[JMD13]

It would be helpful for people like me that use the EQ for low pass filtering so the Q doesnt raise the high freqs when fully open.

[zsliu98]

ZL Equalizer 2 does support 30kHz/40kHz when the sample rate is >= 88.2 kHz.

For sample rate = 441./48 kHz, a low-pass filter at 30kHz or 40 kHz does not exist, because the cut-off frequency must be smaller than the Nyquist. Though you might use a high-shelf to mimic a cut in high frequency area.