Recommended rig
Phone + Bluetooth speaker (30W+) + wired or wireless dynamic mic. Wired 3.5mm is safer than Bluetooth in noisy environments.
Can buskers actually use this live?
Many active buskers use ToneBrowser as their main backing rig. Rehearse a rough key, fine-tune on the day.
Watch out for
Battery and data. Streaming drops if your data drops. Local copyright rules for commercial performance.
Take the music into your own hands.
Download ToneBrowser for free — change the key in 30 seconds.