Hi Kijanki - yes, I do play the French horn. I tried looking up the decibel levels of various instruments quickly, but I would have to dig deep to find it. I know I have it somewhere. Anyway, the actual decibel level possible is not always that relevant to how loud something is perceived. The ear hears the amplitude of different timbres differently. The sound power of the trombone, for instance, is many times that of the French horn, even if both are playing at the same dynamic level. The sound power of a bass drum is more than four times again that of a trombone. And of course, the sound power of all of these instruments exceeds that of the voice. They can also sustain their maximum volumes for a longer period of time, especially in the case of percussion, where they don't have to stop to breathe, and are using much stronger muscle groups to play. Only if we are talking about a relatively short period of time (a long high note at the end of an aria, say) would the unamplified voice be perceived as loudly as a brass instrument, regardless of the actual decibel level.
