Dolby Surround Pro Logic Decoder; Logic7 Decoder; Controls - AKG HEARO 777 QUADRA Mode D'emploi

2 Description
2.6 Dolby Surround Pro Logic
Decoder

2.7 LOGIC7 Decoder

2.8 Controls

2.8.1 Headphones
Refer to figs. 1 and 12.
2.8.2 Transmitter
Front Panel
Refer to fig. 2.
Refer to fig. 10.
12
LH FILTER
RH FILTER
The Dolby Surround Pro Logic decoder integrated in the transmitter uses the stereo input signal to derive
two additional signals, a center and a surround channel. The IVA circuitry generates from these signals a
binaural signal equivalent to reproduction through five high quality loudspeakers (three front, two rear spea-
kers). This allows you to enjoy all the benefits of Dolby surround sound even through headphones.
The integrated LOGIC7 decoder allows recordings in all audio formats (mono, stereo, Dolby Surround,
and LOGIC7) to be accurately reproduced through headphones. Depending on the momentary signal
configuration, two to eight loudspeakers are simulated at any time. Accordingly, the number of simulated
speakers may even change automatically during the same piece.
Also, the LOGIC7 decoder will derive a surround signal from a stereo input signal and is fully compatible
to Dolby Surround.
1. POWER: On/off button surrounded by an annular bicolor status LED (1a).
The status LED will light green to indicate the headphones are ON.
The status LED will light red while the batteries inside the headphones are being charged.
2. Charging contacts for charging the batteries on the transmitter.
2a Charging jack for the optional external charger.
3. Battery compartments (beneath the detachable left-hand ear pad): The battery compartments hold
two NiMH rechargeable batteries electrically isolated from the receiver circuitry by a protective foil.
You cannot charge the batteries before removing the protective foil.
4. AUTOTUNING switch: activates the automatic tuning function
5. VOLUME control
6. ON: Switches the transmitter on (switch illuminates green) and off (switch extinguishes).
7. DISPLAY: Switches the backlighting for all labels except the ON switch and the CHARGE label on and
off.
If you switch the backlighting off, it will come back on automatically as soon as you push any front
panel switch.
If you switch the transmitter off and back on later, the backlighting will come on again, even if you
switched the backlighting off.
8. FREQ: Steps through three fixed carrier frequencies within the frequency band of your headphones
system.
The labels FREQ 1, FREQ 2, or FREQ 3 will illuminate to indicate the selected frequency.
9. MODE: Steps through normal stereo, IVA stereo, IVA plus Dolby Surround Pro Logic, and IVA plus
LOGIC7 modes.
The STEREO, IVA, PRO LOGIC, and LOGIC7 labels will illuminate to indicate the selected mode:
Mode
Stereo
IVA Stereo
IVA Pro Logic
IVA LOGIC7
10. LEVEL: As long as audio signal is present at the transmitter input, the green LEVEL label will flicker
in step with the signal level.
Since signal levels are controlled automatically, the transmitter has no input gain knob.
11. Charging contacts: The transmitter provides charging contacts in the left-hand earphone receptacle.
A: Natural hearing: Due to the
effect of the head and pinnae,
sound waves arriving at one ear
differ from those arriving at the
other. Amplitude and phase diffe-
rences create a sense of spatial
hearing.
B: Listening through headphones:
Amplitude and phase differences
are eliminated. Sound sources are
localized inside the head rather
than in the room.
C: Listening through headphones
with IVA processing: The ear mat-
ching function modifies the audio
signals at the ears to resemble
diagram A. This restores natural,
spatial hearing.
Label
STEREO
STEREO + IVA
PRO LOGIC + IVA
LOGIC7 + IVA