The Decibel scale is a log scale so with the Decibel values in G8 & H8 try:

=LOG10(10^(G8/10)+10^(H8/10))*10

--
HTH

Sandy
In Perth, the ancient capital of Scotland


with @tiscali.co.uk


"SukkyC" <u21136@uwe wrote in message news:5f29858a0c857@uwe...
How do I add dcibels using excel ( I have XP if it makes a difference)?

Thanx in advance.