I already used the speaker as an amplifier for my acoustic guitar. A musician friend of mine used it for a small concert (piano and vocals). He was thrilled and I can't say anything negative about the speaker.
A great active speaker with many possibilities.
Pro+
Size, mobility, sound volume, loudness, clear room-filling sound
Con-
With bass-heavy sound (dance, house, etc.), sometimes too bass-heavy at high volume or easily overflows.
(However, it is not a "boombox" but a multifunctional loudspeaker for music lovers and artists).
No.
Quote from the manufacturer's FAQ:
How can I use instruments or devices with stereo output?
A single S1 Pro Multi-Position PA system can combine the two channels and fill the room with one speaker. For instruments or recorded material where stereo reproduction is essential, two S1 Pro systems can be used to deliver stereo sound.