NAD T775 HD Owner's Manual page 21

AUDYSSEY MultEQ XT ROOM ACOUSTICS CORRECTION
Sound reflecting from room boundaries can disturb the spatial illusion
of surround sound, and can also distort the tonal balance of the system.
Professional Acoustical Engineers often add wall treatments and even move
walls and relocate speakers to improve system performance, but for the
average Home Theatre, this is either too expensive or just not a practical
solution.
Audyssey MultEQ XT, using multiple measurements from the actual
listening positions, and processing this information using very sophisticated
digital signal processing, is able to "precondition" the signal to effectively
make the walls disappear. This creates a 'family size' sweet spot where the
sound and spatial cues are very accurately reproduced.
MultEQ XT is designed to tame room acoustics without changing the sonic
character of your loudspeakers. While it will make the most of whatever
loudspeakers you have, it will not make poor speakers sound like good
ones!
Connect the Audyssey microphone jack into the front panel's MP/MIC input
and the Audyssey Auto Calibration wizard will guide you through a simple
step-by-step configuration. Once setup and calibrated, the next greatest
improvement in performance is obtained by eliminating the acoustic
interference caused by room boundaries interacting with your speakers.
MEASUREMENT IS THE FIRST STEP
The sound at each listening position (up to 8 positions) is calibrated using
the same microphone used during the setup phase.
A special test tone is sent to each speaker and the data is memorized by
the T 775. The duration of calibration may take some time depending on
the number of speakers as well as the number of measuring points. After
all positions are measured, the DSP calculates the ideal system response for
your particular room and speaker setup.
If some inconsistencies or discrepancies are detected during the Audyssey
calibration, the process maybe interrupted or the problem is shown in the
particular setup window. A notice screen is correspondingly displayed.
After following and undertaking the displayed instructions, re-start the
Audyssey calibration again. When the measurements are finalized, Audyssey
calculates the ideal system response for your particular room and speaker
setup.
NOTE
The test tone emitted during measurement is loud. This maybe
bothersome for you and may affect your other household members as
well, and even your neighbor.
NEXT A TARGET CURVE MUST BE CHOSEN
Because loudspeaker designers assume that their products will be used in
typical domestic rooms, they are 'voiced' to work in this environment. It is
assumed that the room will add some bass reinforcement and will absorb
some treble energy. Thus if we effectively 'remove the walls with room
correction, and set the speakers for flat response, you may find this sounds
too bright in the treble and too weak in the bass region.
USING THE T 775 – SETUP MENU
NAD engineers have done extensive research in this area of room acoustics,
and along with Audyssey engineers developed what we believe is the ideal
'in room' response curve. We include this NAD EQ, along with an Audyssey
developed EQ as the two best choices. The response curves shown below
typify NAD EQ room correction process.
Room Response measured by Audyssey microphone
Inverse Correction Filter calculated by NAD T775
Corrected Room Response
Flat EQ is a third option, but not one that we recommend for listening
(it is useful for verifying system performance when using external
instrumentation).
Select the Target Curve you find to be most satisfactory by pressing the
Audyssey key of the remote. The MultEQ XT corrected response can also be
bypassed if you wish.
It is recommended that you take full advantage of the T 775's Audyssey
Auto Calibration feature for your speaker setup. However, if you desire to
setup your speakers manually or if you already had run Audyssey Auto
Calibration but would like to make adjustments, the following sections on
Speaker Configuration, Speaker Levels and Speaker Distance can also be
followed and implemented.
NOTE
During manual setting of your speakers, previously calibrated
Audyssey settings could be retrieved by re-adjusting back the altered
configurations as highlighted by an asterisk.
OPERATION
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