Originally Posted by Warpdrv
Bob can you explain a bit more in detail about how adjusting the room gain will help with measurements.... what will happen if you add more or leave it more towards flat with no room gain added... I don't have alot of room gain because my room is so incredibly large - 8200^3 + other areas in the house.
Room Gain is just another room response characteristic. Unlike room resonance spikes and room cancellation nulls, Room Gain is considered a "desirable" room response -- part of what makes a room sound as you expect it to sound.
ARC detects the natural Room Gain of your listening room and works to preserve it even as it is trying to eliminate the undesirable room response characteristics. Room Gain shows up in the ARC charts as the shallow hump in the Target curves in the vicinity of the crossover frequencies.
Room Gain measuring 2-4dB is pretty typical.
One advantage of maintaining the room's inherent, natural, Room Gain is that sounds that might occur naturally in the room -- such as people talking -- will sound the same when coming from the audio system.
Audio mixes for home theater generally assume some Room Gain. But some rooms, particularly acoustically treated rooms, may have little or no Room Gain. It is also possible for ARC to get confused by a room dip near the crossover frequencies and decide your room actually has no Room Gain (or negative Room Gain which makes no sense). ARC will assign 0dB or near 0dB Room Gain in such cases.
But ARC can be set to "force" a higher Room Gain result to adjust for such cases. However, you don't want to go too far from what the room already measures (so audio system sound stays well matched with natural sound in the room), so I suggest folks seeing that in their ARC Target window try forcing only about 2.0 or 2.5dB of Room Gain to see if they like the sound better.
Some folks prefer little or no Room Gain for Music listening, and ARC lets you adjust that separately if you like. Also if you have a different number of speakers in your Music setup, ARC may detect a somewhat different Room Gain for the room for Music vs. Movie as ARC picks a value that works best with all the speakers in the mix.
Just as with adjusting Max EQ Frequency, you can play around with this without having to re-Measure. Just make the change, re-Calculate, and re-Upload if the Calculated curves look good to you.
Trust your ears. If it sounds better to you, then it IS better.
And you can always do an Auto Detect in the ARC Targets window, which will cause ARC to restore its original Targets values -- including Room Gain -- according to the actual, original Measurements, which are always preserved in your ARC data file. Re-Calculate and re-Upload after that and you are back to what ARC originally set up for you.
In my case, ARC detected 2.9dB Room Gain for Movie and 2.5 Room Gain for Music (which I've set up to exclude the Center speaker) and I've not altered those values.