It appears like the end caps on the YC61 come off by removing (3) screws. Cool idea if Yamaha designed replacement caps with built in speakers.

The YC61 is small & light enough to take anywhere and not have to lug around a sounds system.

The speakers would need a power source same as the YC but could plug into the phones outlet.

I know Bose is a master at full sound without mass or space so it's doable.

I know people use headphones but would be an interesting option if feasible & people were interested enough in the option.