Does It have to be loud?

I'm not sure how they measure, but believe me, most speakers won't even go that loud, or if they do, they will distort tremendously, unless the room is very big, or very well acoustically treated, room interaction will spoil the listening experience.

"I'm not sure how they measure"

with a SPL meter and numerous SPL charts available on the Internet that serve as a frame of reference. 

"but believe me, most speakers won't even go that loud"

Totally and utterly false. There is such a thing as manufacturer specs that can be used to derive the information. That would be in addition to user testimonials by folks like myself that use meters, and have stood next to jack hammers once or twice in their lives. Note I'm speaking of as much as 110db, not 120. 

"or if they do, they will distort tremendously"

Depends on the characteristics of the music being played. The distortion - if any is in fact really audible - is at the higher frequencies. 

"unless the room is very big, or very well acoustically treated, room interaction will spoil the listening experience"

The venue is always part of the equation and overall presentation of the music. Same for live acts. 

So I suppose I'm among those folks who have surprised you, because my system can effortless go to 100db and sound fantastic doing it.

I'm always (practically, not at 2AM in the morning) ready to demo my system to any doubting thomases. I'm in zip 11520. Just PM and we can get the party started. :)

@gdhal

So what max level with an SPL meter did you achieve?

BTW 110 dB is more than 8 times louder than 100...so above 95 db SPL (the max for most speakers at the listening position) it gets very hard very quickly to deliver full dynamic range. (110 dB being 32 times louder than 95 dB)

So what max level with an SPL meter did you achieve?

I'm using a Dawson DSM101N multi-meter, which I realize is by no means a truly scientific exactly perfect measuring device. Also, according to manufacturer specification, it has a range of 40-100db, with .1 db resolution, accuracy ± 3.5%dB at 94dB, 1kHz sine wave. I have read higher than 100db within 2 feet of my speaker drivers, at the midpoint of the speaker cabinet (which in my case is 29 inches off the floor) on a number of occasions. I've read as low as 33db in the early morning hours when all lights are off (but the meter has a backlight), there is no traffic outside, other residents of the building are asleep, etc.

Hitting 100db is easy (with my system), and I typically can hit that level while listening to the drums portion of Grateful Dead performances. Many of the drums songs (stand alone drums, not drums within another song) can be 10 minutes or so long, and often contain very low (below 40Hz) frequencies which also makes achieving 100db easy. I personally like to "feel" bass, not just "hear" it.

The loudest I've recorded on my meter is 107db, during the Nirvana song Breed (from 10/31/91, live at the paramount DVD). In this case I was intentionally attempting to crank the volume for the sake of "checking" how loud it could go, and with whatever clarity or distortion. I maintained that level for nearly the entire song, listening at different spots in the room and measuring SPL at different spots, in particular further away from the speakers. I'm well aware that as distance from the sound source doubles, one could expect a decrease of 6db. This was essentially what I was reading. My PLP is approximately 7 feet of so from the speakers, and at the PLP I was getting readings that were consistent with a 10 db or reduction from the measurement at the speaker.

I also believe my system is capable of even more sound pressure, however, I'm reluctant to play at levels over 100db for any sustained period for various reasons, none of which have to do with system capabilities or sound quality.

If you take the SPL meter while music is playing moderately loud, say average 90 to 95 dB, and measure the SPL in room corners you will notice they are much higher than the average SPL. Around 6-9 dB higher! And there are many other locations in the room where very high sound pressures can be found. Standing waves, first reflections, etc. at room boundaries and out in the 3D space of the room. Maybe even at the listening position, you never know. It’s like having an addition 8 to 20 speakers in the room playing very loud. Anyone see any problem with that? 🙄

@gdhal 

Awesome. If that is continuous at 107 dB (not just peaks) at the listening position that is indeed very loud - more than anyone would care to listen for more than a short period. Congrats!