PRELIMINARY DATA SHEET
MSP 34x1G
2.6.3. Loudspeaker Requirements
2.7. SCART Signal Routing
The loudspeakers used and their positioning inside the
TV set will greatly influence the performance of the vir-
tualizer. The algorithm works with the direct sound
path. Reflected sound waves reduce the effect. So it’s
most important to have as much direct sound as possi-
ble, compared to indirect sound.
2.7.1. SCART DSP In and SCART Out Select
The SCART DSP Input Select and SCART Output
Select blocks include full matrix switching facilities. To
design a TV set with four pairs of SCART-inputs and
two pairs of SCART-outputs, no external switching
hardware is required. The switches are controlled by
the ACB user register (see page 41).
To obtain the approval for a TV set, Dolby Laboratories
require mounting the loudspeakers in front of the set.
Loudspeakers radiating to the side of the TV set will
not produce convincing effects. Good directionality of
the loudspeakers towards the listener is optimal.
2.7.2. Stand-by Mode
If the MSP 34x1G is switched off by first pulling
STANDBYQ low and then (after >1 µs delay) switching
off DVSUP and AVSUP, but keeping AHVSUP
(‘Stand-by’-mode), the SCART switches maintain
their position and function. This allows the copying
from SCART-input to SCART-output in the TV set’s
stand-by mode.
The virtualizer was specially developed for implemen-
tation in TV sets. Even for rather small stereo TV's,
sufficient sound effects can be obtained. For small
sets, the loudspeaker placement should be to the side
of the CRT; for large screen sets (or 16:9 sets), mount-
ing the loudspeakers below the CRT is acceptable
(large separation is preferred, low frequency speakers
should be outmost to avoid cancellation effects). Using
external loudspeakers with a large stereo base will not
create optimal effects.
In case of power on or starting from stand-by (switch-
ing on the DVSUP and AVSUP, RESETQ going high
2 ms later), all internal registers except the ACB regis-
ter (page 41) are reset to the default configuration (see
Table 3–5 on page 20). The reset position of the ACB
register becomes active after the first I2C transmission
into the Baseband Processing part. By transmitting the
ACB register first, the reset state can be redefined.
The loudspeakers should be able to reproduce a wide
frequency range. The most important frequency range
starts from 160 Hz and ranges up to 5 kHz.
Great care has to be taken with systems that use one
common subwoofer: A single loudspeaker cannot
reproduce virtual sound locations. The crossover fre-
quency must be lower than 120 Hz.
2.6.4. Cabinet Requirements
During listening tests at Dolby Laboratories, no reso-
nances in the cabinet should occur.
Good material to check for resonances are the Dolby
Trailers or other dynamic sound tracks.
Micronas
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MICRONAS [ MICRONAS ]
