loudness requires electricity from the amplifier and magnets that are strong.
if either one doesnt exist, the loudness wont exist.
i highly doubt any of those systems output 1,000 watts at an RMS level.
the situation would be bad for your ear's health.
but
that doesnt stop the stupid movie producers that do the audio.
the loud peaks are strong enough to use up 1,000 watts.
although, that 1,000 watts might be what is used to throw the cone outwards and leave it there.
do that for 7 speakers at the same time and you could get up to 2,000 watts for a quick burst.
some of those watts might be going to the subwoofer and included in the total watts for the system.
subwoofers can eat up a lot of peak watts to throw the cone out really fast and leave it there.
some more watts can be eaten up if the cone gets thrown out and sucked back in as the capacitors go empty (or do they hold?).
those numbers are there for a reason.
and it only takes common sense to realize there is not going to be 1,000 watts of midrange and treble screaming at you.
your children could go deaf if they play around with the stereo at loud volumes when you or the babysitter isnt around (or fell asleep)
basically that boils down to the company getting sued for providing something dangerous without a warning shoved up in their face.
most of the watts is actually current that is used for the dolby and dts surround sound formats.
you know a speaker moves in and out.
but if you zoom in with a video camera and watch the cone move in and out.. when it rests in the exact middle.. that is where all the electricity is going.
it controls the speaker during its travel.
more amperage = more realistic audio.
the electricity doesnt slap the speaker cone forwards and backwards.
the electricity grabs the speaker and holds onto it for the whole time.
so yea.. 1,000 watts doesnt mean it is going to be loud.. but it should sound good if the speakers are worth anything.
the option is..
the electricity grabs onto the speaker and holds it.
or
those obnoxious loud parts in a movie send lots of watts to the speakers and the speakers simply suck up the extra voltage after the volume gets higher.
so yea..
you are either using it or wasting it.. or you will blow some speakers that doesnt have a very high peak rating.
how many cheap speakers have you seen with a 300 watt RMS value .. and a 1,500 watt peak rating?
these types of speakers will eat up all of the extra watts from the stupid movie audio peaks.
most people into car audio already know.. most speakers say 300 watts RMS and 600 watts peak.
but some of them say 300 watts RMS and 1,500 watts peak.
**edit**
cant guarantee anything future-proof.
but
the absolute best advice you could get about the future is..
make certain the receiver will do 24-bit 192khz.
the new dolby and dts surround sound formats do those bit-depths and sample rates.
those two values are rather new.. and they should be around for a while.
but
they are expected to go up again.
it could be 'super audio disc' format.. or a new type of dvd/blu-ray upgrade.
if you can get 24-bit 192khz from all of your speakers.. i wouldnt worry about it for the next 10 years.
some of us might hope for 32-bit audio though.