Loud music is free speech?

Stopped at a red light, the amplified sound emanating from the car next to you actually seems to rock the vehicle. For some motorists, that intrusive noise rises to the level of a public nuisance.

But Florida’s Supreme Court ruled last week that motorists can play their car stereos as loud as they want. They struck down parts of a state statute that barred drivers from blasting car radios at a volume “plainly audible” to someone 25 feet away.

A court majority called that overreach and struck down parts of the law, saying it “infringed on the freedom of expression.”

A Tampa lawyer who got a $73 ticket for violating the noise law brought the case. He was listening to Justin Timberlake on his way to work one morning when stopped and given the citation.

He took the case to court, challenging the law’s constitutionality, and it wound up going from circuit court to the 2nd District Court of Appeal, which also found the law overly broad.

Last week’s decision upholds the 2nd District opinion, although the Supreme Court justices didn’t cite the constitutionality argument. Instead, they focused on First Amendment rights that guarantee free speech.

Source

I can't find any mention of the volume of "speech" in the First Amedment protection.  Presumably speech has to be audible but anything beyond that seems an over-reach