Originally Posted by TK Doom
So, i'm engaged, getting married June 8, fiance and I regularly go the movies, where its obviously LOUD. Especially IMAX.
We are building a HT and my HT can match the theater for loudness. However, significant other does not like it as loud at home.
is this normal? She says "room is too small" (compared to theater), and I said, SPL is SPL, am I right in that regards?
I took my SPL meter to Iron Man 3, and was hitting 100s regularly, which I could match in my HT if I wanted, but she doesn't like it.
I love it loud...I'm just curious or is my fiance an anomaly?
TK, your fiancé is right! And no, she's not an anomaly!
In a way, all SPL's are not created equal. Perhaps the best explanation I've seen is from Mark Seaton here:
Unfortunately simple SPL readings on a meter in one space does not equal the same reading in another space. I've posted about this any times, but until someone makes their own comparison/observation with a meter in hand, it's easy to remain skeptical.
Here's the short explanation. Our ears and hearing system generally determine loudness by sound power over different time intervals. In terms of sound, power is intensity over time. In other words a brief transient of a given max SPL is perceived to be less loud than a sound of the same intensity lasting 5-10x longer. After some longer time period we move to a perceived average level, like what is noted for industrial/machinery noise and loud rock concerts.
In a shorter time period, measured in milliseconds to a few seconds, duration is everything. This is where room acoustics, distortion, and compression come into play. Room acoustics are the most dominant, with amp/speaker systems and program material differences following behind.
This is what 67Jason was alluding to above. In a well treated room, the energy of the loud transient peaks are attenuated quickly, allowing you to better hear the quieter bit immediately following and therefore not perceiving a more elevated average loudness level. In an untreated or more reflective room, the loud short duration peaks don't decay as fast and will "pollute" the quieter bits, therefore moving you to perceive a higher average level... the whole lot sounds louder. This really just describing the "dynamic range" of the room and is not about whether the equipment is straining or distorting (although that can contribute).
Anecdotally at least, the close confines of a typical domestic room, as compared to the space of a cinema (for which the soundtrack was originally designed for) and the proximity of the sound sources to the listener can also contribute to the movie soundtrack feeling overbearing or "too big" for the room.
TK, you are a wise man to get this sorted out now! Just make sure you run the possibility of some "aesthetically pleasing", room treatments up the flagpole before June 8! If the bride to be has reservations now... you'll be no chance afterwards!!!