VS1053B Datasheet, PDF (41/79 Pages) List of Unclassifed Manufacturers – Ogg Vorbis/MP3/AAC/WMA/MIDI AUDIO CODEC

VLSI
Solution ^y
VS1053b preliminary
VS1053B
8. FUNCTIONAL DESCRIPTION
8.7.3 SCI BASS (RW)
Name
ST AMPLITUDE
ST FREQLIMIT
SB AMPLITUDE
SB FREQLIMIT
Bits
15:12
11:8
7:4
3:0
Description
Treble Control in 1.5 dB steps (-8..7, 0 = off)
Lower limit frequency in 1000 Hz steps (1..15)
Bass Enhancement in 1 dB steps (0..15, 0 = off)
Lower limit frequency in 10 Hz steps (2..15)
The Bass Enhancer VSBE is a powerful bass boosting DSP algorithm, which tries to take the most out
of the users earphones without causing clipping.
VSBE is activated when SB AMPLITUDE is non-zero. SB AMPLITUDE should be set to the user’s
preferences, and SB FREQLIMIT to roughly 1.5 times the lowest frequency the user’s audio system can
reproduce. For example setting SCI BASS to 0x00f6 will have 15 dB enhancement below 60 Hz.
Note: Because VSBE tries to avoid clipping, it gives the best bass boost with dynamical music material,
or when the playback volume is not set to maximum. It also does not create bass: the source material
must have some bass to begin with.
Treble Control VSTC is activated when ST AMPLITUDE is non-zero. For example setting SCI BASS
to 0x7a00 will have 10.5 dB treble enhancement at and above 10 kHz.
Bass Enhancer uses about 2.1 MIPS and Treble Control 1.2 MIPS at 44100 Hz samplerate. Both can be
on simultaneously.
In VS1053b bass and treble initialization and volume change is delayed until the next batch of samples
are sent to the audio FIFO. Thus, unlike with earlier VS10XX chips, audio interrupts can no longer be
missed when SCI BASS or SCI VOL is written to.
Version 0.5, 2007-12-03
41