the internal speakers recently stopped working on my mid 2011 mac. this machine is in great shape with low hours. the internal speakers aren't listed as an option to select.
the internal speakers quit working
iMac 27″, macOS 10.13
Question marked as
Have you done a PRAM reset, CMD+Option+p+r...
Reset NVRAM or PRAM on your Mac - Apple Support
In fact, do 3 in a row, takes a bit of time.
Intel-based Macs: Resetting the System Management Controller (SMC)...
How to reset the SMC of your Mac - Apple Support