Car stereo boot-up question.

While the few new cars I have owned over the last ten years or so have had reasonably good quality audio systems, one particular feature of the newer radios that bugs me a bit is the time they take to produce sound after being switched on.

Even the Audi Sound system in my new Audi takes around 5 secs. from switch-on to hearing radio/music.

Many years ago I recall having good car audio systems - Pioneer, Sharp etc as aftermarket and they produced sound instantly after being switched on.

Is there any current car audio system that comes on immediately, without a lag?

Indeed I got a new home stereo (Marantz) last year to replace my 25 yrs. old system and the new one takes several seconds to boot up too. Kind of ironic that the older systems, both in-car and in home, did somethings better than the new 'state-of-the-art' ones.