YMF744B

2-2-2. Sound Blaster Pro Mixer

The following shows the register map of the Mixer section of Sound Blaster Pro.

Address

b7

b6

b5

b4

b3

 

b2

 

b1

b0

Remark

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

00h

 

 

 

Reset

 

 

 

 

 

 

04h

Voice Volume L

"1"

Voice Volume R

"1"

 

 

 

 

 

 

 

 

 

 

 

 

0Ah

-

-

-

"1"

-

 

 

MIC Volume*

 

0Ch

-

-

Ifilter*

"1"

 

Input Source*

"1"

 

0Eh

-

-

Ofilter*

"1"

-

 

-

 

St. SW

"1"

SB Pro Mixer

22h

Master Volume L

"1"

Master Volume R

"1"

 

 

 

 

 

 

 

 

26h

MIDI Volume L

"1"

 

MIDI Volume R

"1"

 

 

 

 

 

 

 

 

28h

CD Volume L*

"1"

 

CD Volume R*

"1"

 

2Eh

Line Volume L*

"1"

 

Line Volume R*

"1"

 

 

 

 

 

 

 

 

 

 

 

 

 

F0h

SBPDA

-

-

-

SS

 

SM

 

SE

SBPDR

Suspend / Resume

F1h

 

 

 

SCAN

DATA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

F8h

-

-

-

-

-

 

-

 

-

SBI

IRQ Status

 

 

 

 

 

 

 

 

 

 

 

 

The registers marked with * exist, but do not function.

DS-1S does not have the circuit that corresponds to the SB Mixer. Therefore, the volume settings on the SB Mixer are converted to the DSP coefficients of DS-1S or to AC’97 register values.

The conversion for each case is described below.

(1) SB Mixer ® DSP

The volume of master, MIDI and Voice, are applied to this case.

When the SB register is set, a 14-bit coefficient value is determined from the following conversion table and used as the DSP coefficient. The attenuation value of Master Volume, MIDI, and voice are summed together to obtain the coefficient.

These volumes cannot be controlled from PCI Audio block.

February 3, 1999

-38-

Page 38
Image 38
Yamaha YMF744B (DS-1S) specifications Sound Blaster Pro Mixer, SB Mixer DSP

YMF744B (DS-1S) specifications

The Yamaha YMF744B, also known as the DS-1S, is a popular audio chip that emerged in the late 1990s, particularly known for its use in sound cards for PCs. This sound processor exemplifies Yamaha's commitment to delivering high-quality audio through innovative technology and user-friendly features.

One of the standout features of the YMF744B is its ability to support advanced sound synthesis methods, including wave table synthesis and sample playback. These technologies provide users with a rich audio experience, enabling high-fidelity sounds reminiscent of live instruments. The chip is also notable for its ability to emulate MIDI instruments, allowing musicians to create synthesized music that captures the nuances of traditional sounds.

The YMF744B integrates a 16-bit DAC (Digital-to-Analog Converter), which facilitates high-quality audio playback with a sampling rate of up to 48 kHz. This capability ensures that sound reproduction remains clear and devoid of distortion, appealing to both casual users and audio professionals alike. Additionally, the chip supports multiple audio channels, making it ideal for gaming and multimedia applications where spatial audio is crucial.

Another significant feature of the YMF744B is its support for various audio formats, including PCM (Pulse Code Modulation), ADPCM (Adaptive Differential Pulse Code Modulation), and even MIDI. The versatility in format support allows users to interact with a broad spectrum of audio applications, from game design to music production.

The chip also comes with integrated Sound Blaster Pro compatibility, which significantly enhances its usability with a vast array of software and games designed during the 1990s and early 2000s. This compatibility is crucial for retro gaming enthusiasts who seek an authentic audio experience with classics from the past.

Moreover, the YMF744B champions power efficiency, making it an attractive choice for mobile computing platforms. Its low power consumption means that it can be effectively used in laptops without significantly draining battery life, allowing users to enjoy high-quality sound on the go.

In summary, the Yamaha YMF744B (DS-1S) stands out due to its advanced audio synthesis capabilities, high-quality playback features, and compatibility with multiple formats. These attributes make it a favored choice in the audio processing domain, continuing to impact computer audio technology long after its initial release.