How loud is loud, What DB is actually loud?

Al,

Play your system in mono, turn of one channel , guarantee you will have more than a 3db loss, even after factoring losses you will still have a 4.5-5 db min drop, the theoretical difference would be 6 db.

regards,

Al,

Tell the university guys there is such a thing as room gain ..

regards,

The 3 db gain is correct for free space ( anechoic) go ahead and measure your hi-fi system, with speakers l/r and with room gain it is more than 3 db, when you turn off one side from the listen position.

regards,

"Play your system in mono, turn of one channel , guarantee you will have more than a 3db loss"

Yes, but not because of the smaller radiating area but because you cut off half of the power.

yes, there is room gain, but since it applies to both speakers it disappears when you'll take the difference - the gain is still 3dB.

I must be missing something - I would thing that if one speaker is creating certain SPL at my sitting position (including room reverberation) second exactly same speaker will double this SPL. Doubling SPL means 3dB increase

Very good write up of all this sort of stuff at www.phys.unsw.edu.au/jw/musFAQ.html (FAQ in music acoustics). In particular, "Does adding two equal sounds give an increase of 3 or 6 dB? Why?" is explained very clearly.

Frank