1) Why would this be true? Is there something about the area of the radiating speaker surface or size of the front of the speakers that somehow impacts how I perceive the same measured SPL volume? Is it because I am using pink noise to set levels?
More likely its because your ears are not microphones. More to the point, our sensation of hearing volume is nothing like what a meter measures.
Meters measure atmospheric energy. They are directional, and they are linear. At least compared to our ears they are linear. Do a search for Fletcher-Munson equal loudness contours to see graphically just how NON linear our hearing is.
Mainly though I think the difference is because what we hear and perceive as volume is the sum total of all the sound in the room. Your meter is pointed straight at the speakers. Your ears are pointed straight off to the sides. The meter is highly directional. Your ears are highly omnidirectional.
Just one of the many, many reasons I determined long ago that meters are at least as likely to mislead and harm as enlighten and help.
2) One of the reasons to set the SPL levels at 75 dB is to minimize the risk of any hearing loss. If I turn up the measured dB to 80+ with the smaller speakers but it is perceived the same as 75 db on the bigger speakers does that increase the risk of listening ?
Yeah well there’s a new one: "the risk of listening"! What about the enjoyment of listening, eh?
If you’re really afraid of hearing loss well then I’m afraid I have some bad news: you are gonna have hearing loss. It gets worse as we get older. Fact of life.
But here’s another fact of life: we gain experience. Little kids hear way better than we do. But would you rely on one to evaluate anything audio? I don’t think so. My hearing on the other hand, when I play my test CD it keeps sweeping up the frequencies long past the point it tapered off into dead silence, for me. Yet I think you would agree I somehow have managed to put together a pretty darn fine system.
So hearing ain’t all that. Listening is. Hearing is bio-mechanical. Listening is an intellectual activity. Two related yet fundamentally completely different things.
But high volume levels can do real damage over time. Very high levels. Very long time. Also the type or nature of the sound matters a lot. Riding in a car might be only about 75dB but its steady wind and road noise and that is a lot worse than music that might measure an average 75 but contain peaks to 95 while being below 70 a lot of the time.
You should come back again when you get the chance. Sounds way, way better now. Like you would not believe how much better. Like the same stuff had you longing for more afterwards? Well now there’s way more of that. Just maybe next time less talking trying to figure out what might be going on, more time listening absorbing what actually is going on. I will meet you half way and get out my trusty Radio Shack SPL meter so we can quantify exactly how much damage (enjoyment) the Moabs are dishing out. What do you say?