[pbc]

Here is the soundcard cal reading:

Sample rate: 48000Hz
-3dB points: 7.7Hz, 20.993kHz
Input device: Line In (Realtek High Definition Audio)
Input: LINE_IN (Master Volume)
Channel: Right
Input volume: 0.422
Input RMS target: -12.0dB
Actual RMS at 1kHz: -11.6dB
Output device: Speakers (Realtek High Definition Audio)
Output: Master Volume
Sweep level: -12.0dB
20Hz .. 20kHz flatness: +0.0, -1.3dB
1kHz 2nd harmonic: 0.002%
1kHz 3rd harmonic: <0.001%