MAS3549F datasheet(50/92 Pages) MICRONAS

50 / 92 page

MAS 35x9F

DATA SHEET

June 30, 2004; 6251-505-1DS

Micronas

Micronas Bass (MB)

00 22

MB Effect Strength

bit[15:8]

00hex

MB off (default)

7Fhex

maximum MB

The MB effect strength can be adjusted in 1dB steps. A value of 40hex will

yield a medium MB effect.

MB_STR

00 23

MB Harmonics

bit[15:8]

00hex

no harmonics are added (default)

64hex

50% fundamentals + 50% harmonics

7Fhex

100% harmonics

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.

MB_HAR

00 24

MB Center Frequency

bit[15:8]

20 Hz

330 Hz

...

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

MB_FC

00 21

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_SHAPE

MB Switch

bit[7:2]

reserved, must be set to zero

bit[1]

MB switch

0MB off

1MB on

bit [0]

reserved,must be set to zero

MB_SWITCH

Table 3–16: Codec control registers on I2C subaddress 6C

hex, continued

Address

(hex)

Function

Name

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