Speaker db rating?


Does anyone knowthe ratio of a speakers db rating, 1 db at 1 meter,relitive to amplifier watts to power them well enough to be loud enough in a small room.
Example:what kind of db rating would one look for if a 8 watt amplifier was used?
How does each point,as the rating increases,affect the wattage needed to drive the speaker.
Thanks
G.H.
groundhog
Hi: Other thing to take in count is how much power do we need for transients ?, maybe we can be safe about with an amplifier headroom of 5-6db for distortion free performance.

Regards and enjoy the music.
Raul.
Groundhog- Refer to the websites cited for the facts. Also: Remember that tube amps always provide more listenable volume than their rated wattage will indicate. Happy shopping and listening.
Thanks everyone for all your info.There is a lot of study up I will have to do here.I believe there is enough information to keep me busy for quite some time.
G.H.