Certainly. * Passive speakers: no microcontrollers at all. Prices from tiny to extravagant. * Class-D amplifier: no facility to update the firmware. Prices fr

Certainly. * Passive speakers: no microcontrollers at all. Prices from tiny to extravagant. * Class-D amplifier: no facility to update the firmware. Prices from small to extravagant. * USB DAC: no facility to update the firmware. Prices from tiny to extravagant. * Laptop running anything that outputs to USB Audio spec: pick your poison. At the low end, this could be a pair of JBL A130 (under $200/pair on sale), an Aiyama A07 amp ($80), a $10 Apple DAC, and $20 in wires. It's loud enough for a living room, not for an outdoor party. Substitute in Behringer B215 powered speakers for the JBL and Aiyama components, adding about $400 to the total bill, and you should have a pretty good outdoor small-concert system. You'll need power for all this. There are an infinite number of solutions in this space; the above two are just examples.