Hi I was wondering if 143.7 decibles loud for a car sound system. And how does it all work?

Yes, 143.7 decibels is very loud! It is compared on the following site to a military jet taking off.

Intensity and the Decibel Scale

The site is worth checking out!

Don't forget to take the self test at the bottom!

You didn't ask, but I think 143.7 db is too loud for any practical use. People who listen to anything this loud become deaf relatively quickly.

The medical researchers at the National Institutes of Health say:

"Sources of noise that can cause hearing loss include motorcycles, firecrackers, and small firearms, all emitting sounds from 120 to 150 decibels. Long or repeated exposure to sounds at or above 85 decibels can cause hearing loss. The louder the sound, the shorter the time period before hearing loss can occur."

It seems obvious that listening to a music system emitting 144 db even for a short time would cause permanent hearing loss.

Noise-Induced Hearing Loss

As asking said anything generally over 90 is damaging to the ear drums

Great site Clough, didn't find the scale yet, but found 1 with "Boom Cars":

Decible Sound Ruler

Strat, this thread is from 2008.

They slip through sometimes?

I guess so, or you just don't have enough to do.