Originally Posted by Kemet
Audyssey killed my dynamic range.
Using Onkyo 805 with Axiom M22 Fronts & Center (91-93 sensitivity). Reference was set as 0 confirmed as 75db using the receiver test tones and source level set to 75db also confirmed using DVE limited pink noise test tones at seating position 2.5m away.
With Audessy enabled playing DVE test tones at 0 relative receiver volume gives 75db of course. Increasing to +15 reference reciever volume gives only 78db
With Audyssey disabled on playing DVE test tones: reference = 75db, and +15 reference = 88 db, more as expected.
Playing a music track with Audyssey enabled at reference, 87db peaks. The +15 setting would only get +2db more
Playing same track with Audessy disabled at reference = 103db peaks.
Why does audyssey suck the dynamics out?
Ah yes, you have stumbled into the wonderful world of Volume ICs. This is the little chip that is responsible for managing the volume, in fact it manages the entire gain structure in the receiver.
In a receiver today there are numerous functions that require headroom. These include: dialog normalization, subwoofer trim, main channel trim, downmixing, tone control, MultEQ XT.
For example, MultEQ requires 9 dB of headroom to avoid clipping. The channel trims require 12 dB of headroom to allow for the maximum setting. Downmixing requires up to 12 dB of headroom.
When some or all of these processes are enabled the maximum playback volume will be limited to the maximum headroom available in the Volume IC chip selected by the manufacturer. You may also notice that if you listen to 2 channel material you can turn the volume up higher than when you listen to multichannel content.
What trim values are you seeing after MultEQ is finished with the calibration? If one or more of them are in the high positive range then this would be part of the reason for the volume limitation that you are experiencing.
Every manufacturer deals with the volume display a little differently. In the 805, once you get past a few dB above reference the volume no longer increases if you have reached the maximum headroom of the Volume IC chip. The point at which that happens will depend on what processes are running at the time. Unfortunately, the display on the 805 continues to show the number increasing up to +15. Onkyo has told us that they will change that in future versions.