MSP 34x1G
PRELIMINARY DATA SHEET
2.5.5. Micronas Dynamic Bass (MDB)
The Micronas Dynamic Bass system (MDB) extends
the frequency range of loudspeakers or headphones.
After the adaption of MDB to the loudspeakers and the
cabinet, further customizing of MDB allows individual
fine tuning of the sound.
The MDB is placed in the subwoofer path. For applica-
tions without a subwoofer, the enhanced bass signal
can be added back onto the Left/Right channels (see
Fig. 2–1 on page 9). Micronas Dynamic Bass com-
bines two effects: dynamic amplification and adding
harmonics.
Frequency
MDB_HP
Fig. 2–6: Adding harmonics
2.5.5.3. MDB Parameters
Several parameters allow tuning the characteristics of
MDB according to the TV loudspeaker, the cabinet,
and personal preferences (see Table 3–11). For more
detailed information on how to set up MDB, please
refer to the corresponding application note on the
Micronas homepage.
2.5.5.1. Dynamic Amplification
Low frequency signals can be boosted while the output
signal amplitude is measured. If the amplitude comes
close to a definable limit, the gain is reduced automati-
cally in dynamic Volume mode. Therefore, the system
adapts to the signal amplitude which is really present
at the output of the MSP device. Clipping effects are
avoided.
2.6. Virtual Surround System Application Tips
2.6.1. Sweet Spot
Good results are only obtained in a rather close area
along the middle axis between the two loudspeakers:
the sweet spot. Moving away from this position
degrades the effect.
MDB_LIMIT
2.6.2. Clipping
Frequency
MDB_HP
MDB_LP
SUBW_FREQ
For the test at Dolby Labs, it is very important to have
no clipping effects even with worst case signals. That
is, 2 Vrms input signal may not clip. The SCART Input
Prescale register has to be set to values of 19hex
(25dec) or lower (see SCART Input Prescale on page
30).
Fig. 2–5: Dynamic amplification
2.5.5.2. Adding Harmonics
MDB exploits the psychoacoustic phenomenon of the
‘missing fundamental’. Adding harmonics of the fre-
quency components below the cutoff frequency gives
the impression of actually hearing the low frequency
fundamental. In other words: The listener has the
impression that a loudspeaker system seems to repro-
duce frequencies althoug physically not possible.
Test signals: sine sweep with 2 VRMS; L only, R only,
L&R equal phase, L&R anti phase.
Listening tests: Dolby Trailers (train trailer, city trailer,
canyon trailer...)
14
Micronas
MICRONAS [ MICRONAS ]
