a) When AC output is between 0-400W, the sound level is around 42 dB at 1 meter from RIVER, which is similar to the sound level in the library.
b) When AC output is between 400-600W, the sound level is around 48 dB at 1 meter from RIVER, which is similar to the sound level in the office.
c) When charging RIVER through X-Stream AC input, the sound level is 45 dB at 1 meter from RIVER, which is similar to the sound level in the office.
d) When charging RIVER under the quiet mode, the sound level is 40 dB at 1 meter from RIVER, which is similar to the sound level in the library.