Denon AVP-A1HD - Page 10

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+10dB boosts on my dipole/bipole surround
channels and up to +5dB boosting on
my mains. I also measured the preamp
outputs of the main channels (above right
pic) to quantify the results. The red trace
represents no Audyssey while the yellow
trace is “Audyssey” and the blue trace is
“Flat”. It’s interesting to note an overall
drop in signal level when either Audyssey
calibration is engaged with a rather dramatic
boost in the high frequencies in “Flat” mode.
I am very eager to do some curve editing to
minimize the boosting while tweaking other
areas in the bass response.
Volume Scaling Issue
Upon getting my AVP-A1HDCI fully
calibrated, I was prepared to start doing
some listening tests. I started out with a
few CD’s engaged in PLIIx Music Mode. The
system sounded great as I kept pumping up
the volume and was a bit perplexed that I
quickly hit max volume and it wasn’t all that
loud. There I was with a $14k separates rig
from Denon which was barely sustaining
85dB SPL levels in my theater room. What
gives, I asked myself? I soon realized that
once I engaged Audyssey, it severely limited
the max volume level in the AVP-A1HDCI.
Upon further investigation, I discovered it
wasacombinationofAudyssey+7.1post
processing surround Mode (ie. PLIIx Music
Mode, DTS, Neo, etc) that was leading to
this problem. Combine this deficiency when
listening to a low compression source with
an inherently low signal level, and you’ve got
a receipt for severe volume limiting. I ran
into this scenario quite often when using my
Toshiba HD-A2 HD DVD player to playback
discs recorded in Dolby TrueHD and even
after I boosted the input level by +10dB
and turned Audyssey off, I still found myself
wanting to turn the volume higher than it
would let me.
What appeared to be happening is an
issue with the overall gain structure and the
demands from multiple processes placed on
the volume IC’s utilized in this product. The
list of processes that require headroom is
quite long which includeTHX, Subwoofer
gain compensation (up to +8 dB), channel
trims (up to +12 dB), downmixing (up to
+11 dB of headroom in the worst case),
Tone control, MultEQ (up to 9 dB), and
others. So, in a worst case scenario (e.g. if
you are in downmixing mode and the trim
on your sub is near the max, or perhaps
tone control is on) you will not be able
to reach master volume indication above
0 dB. Denon is NOT alone here. Other
manufacturers are facing this issue but
they are a bit more clever hiding it. For
example, I’ve come to find out that the
latest generation of Onkyo receivers have
a similar issue, but the volume indicator will
always allow the user to reach max volume
despite it won’t continue to get any louder
beyond a certain point.
An industry insider has indicated to
me that a new technology is enabling
Volume IC chips with higher headroom and
they will start to become available next
year. Unfortunatelythisdoesnogoodfor
consumers facing this problem now with
the current generation of products, but I
do have some suggestions to help minimize
the impact.
• Scaledownyourchanneltrims–ifyou
have your sub boosted to +3dB, scale
it back to 0dB while also scaling back
all other channels by 3dB
• Ifthesublevelswereboostedin
the processor during setup, adjust
them down to 0dB or lower and
proportionally increase their
respective levels via your subwoofer(s)
master volume control
• Increasesourcelevelperinputas
needed
• IfusingthePOA-A1HDCI,bridge
the front channels if you’re got two
channels to spare. This will increase
your output level by +6dB
• Don’tusetonecontrolsordownmix
options
Audyssey Equalization Results: Denon report (left pic); Actual measurement (right pic)