I have a very old Mac, white Unibody 2009. High Sierra 10.13.6 with upgraded 8GB and SSD.
I also have a iPhone SE.
The speakers on my old Mac are past their best and the volume from my iPhone can get louder. Since my apartment has a lot of street noise I was hoping that I could use my iPhone as a speaker without having to buy a separate speaker.
I found an app 'Airfoil' which, I think, uses Airplay to play sound from one device on another.
While trying to stream video with this app on both my phone and my Mac, everything works perfectly except for the lag. There's a 3 to 4 second delay from what I see visually on my Mac and what I hear via my iPhone.
I wondered if there are any alternative solutions, perhaps by having my iphone plugged in with a USB?