[guf]

I went to CES and checked out a few of the rooms. The Pass Labs room was a huge suite. I sat and listened for a few minutes, from about 3 or 4 meters away from the speakers. I was curious about the spl levels so I used my app on my iphone and surprised it was maxing out above 100. It didn't seem very loud but averaged high and peaked out high.  Now sitting at home in my 13 by 19 room just 2 meters away from the speakers averaging in the 70's and peaking at 92. I could not imagine it being any louder and have it be comfortable. Is there a logical reason for this or am i hallucinating.    Does room size affect perception? or are there other variables i'm not taking into consideration.

[JLM]

Glad you could make it to CES, but not sure what your mean by "averaged high and peaked out high."

You may have crossed what I term the 'threshold of annoyance' which broadly applies to any sonic irritation.  Different sounds are palatable up to varying sound pressure levels (volume).  For instance your favorite music versus nails across chalkboard, or  your least favorite music at 80 dB, or a 3 year screaming would all have different 'thresholds of annoyance'.  The same would hold if you compare playback on a crummy system driven into distortion versus a very fine system at the same sound pressure levels.  Keep in mind that the threshold of sounding loud (or too loud - annoying) can also vary by your emotional state. 

The same phenomenon can be applied to a variety of audio distortions (conscious or subconscious) and can range from measured equipment distortions, speakers that cannot produce a coherent sound across a full frequency range, a system that cannot properly image, "un-flat" in-room frequency response (very typical for bass), or a poor recording.  In many such cases the annoyance is due to listener fatigue based on the brain trying to resolve what it knows a particular piece of music should sound like.


In general:

The bigger the room the better (small rooms have quick reflections, additional travel distance of 11 feet is the critical distance/time delay that the ear cannot separate from the direct sound, and small rooms simply reflect more sound so have more of an effect on what is heard) 

Associated with bigger the better is use of near field listening to add reflected travel distance (move away from walls and so reduce room effects)

Room shape is critical (avoid simple multiples of width, length, and height to minimize the frequencies where reflections across one room dimension reinforces another)

Distributed bass is essential (bass produced at the end of the room behaves like a hand moving the length of a shallow bath tub of water, creating waves that travel the length of the tub and return to either double or cancel the next wave, for bass this can translate into +/- 20 dB and would be frequency/location dependent).

Room treatments are bandaids for not properly addressing the above issues.  EQ is best left as the final step and applied lightly.

[Guy 13]

Hi JLM and all Audio Circle members.
Even if this post was not for me, I always enjoy reading your post.
You are well informed and you put it in such a simple way
that even an idiot like me can understand, well,
most of the time anyway.
Thanks.

Guy 13

One day, I may ask you to transfer your knowledge into my half full audio brain.
The subject will be about multiple subwoofers. I have four 12" Eminence Acoustinator with two GR Research SA-1 (200watts) plate amplifiers that are gattering dust on a shelve in my office. I would sure like to put them to use and improve the bass (Quality) in my listening room.
If you don't minf of course, will get back to you one of those days.
Sorry Guf, if I have used your post for my personal use,
I will try not to do it again.