MAS 35x9F
DATA SHEET
2
Table 3–16: Codec control registers on I C subaddress 6C , continued
hex
Register
Address
(hex)
Function
Name
Micronas Bass (MB)
00 22
MB Effect Strength
MB_STR
MB_HAR
bit[15:8]
00
7F
MB off (default)
maximum MB
hex
hex
The MB effect strength can be adjusted in 1dB steps. A value of 40 will
yield a medium MB effect.
hex
00 23
MB Harmonics
bit[15:8]
00
64
7F
no harmonics are added (default)
50% fundamentals + 50% harmonics
100% harmonics
hex
hex
hex
The MB exploits the psychoacoustic phenomenon of the ‘missing fundamental
by creating harmonics of the frequencies below the center frequency of the
bandpass filter (MB_FC). This enables a loudspeaker to display frequencies
that are below its cutoff frequency. The Variable MB_HAR describes the ratio
of the harmonics towards the original signal.
00 24
MB Center Frequency
MB_FC
bit[15:8]
2
3
20 Hz
30 Hz
...
30
300 Hz
The MB Center Frequency defines the center frequency of the MB bandpass
filter (see Fig. 3–5 on page 52). The center frequency should approximately
match the cutoff frequency of the loudspeakers. For high end loudspeakers,
this frequency is around 50 Hz, for low end speakers around 90 Hz
00 21
MB Shape
MB_SHAPE
bit[15:8]
5...30
corner frequency in 10-Hz steps
(range: 50...300 Hz)
With a second lowpass filter the steepness of the falling edge of the MB band-
pass can be increased (see Fig. 3–5 on page 52). Choosing the corner fre-
quency of this filter close to the center frequency of the bandpass filter
(MB_FC) results in a narrow MB frequency range. The smaller this range, the
harder the bass sounds. The recommended value is around 1.5 × MB_FC
MB Switch
MB_SWITCH
bit[7:2]
bit[1]
reserved, must be set to zero
MB switch
MB off
MB on
0
1
bit [0]
reserved,must be set to zero
50
June 30, 2004; 6251-505-1DS
Micronas
MICRONAS [ MICRONAS ]
