★ HARDWARE Manual ★ Sega Saturn Overview Manual
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■ 3.5 SCSP

SCSP is a custom sound LSI that combines a PCM (FM) sound source and a dedicated sound DSP.
The audio function is highly functional and has high sound quality, and various interfaces are available in consideration of future expandability. In addition, the arithmetic unit also has performance close to that of a synthesizer, and can produce a large number of sounds.
The DSP section can also create multiple sound fields such as various sound field reproductions and special effects for 3D sound localization.

● System configuration

The main CPU, sound CPU, sound memory, and D / A converter are connected to the SCSP. These can operate independently of the main processing in this sound system.
The main CPU transfers the sound (CPU, DSP) program and waveform data to the SCSP sound memory via the SCU. The sound CPU transfers the waveform data to the SCSP's internal registers. SCSP reads the waveform data in the sound memory and the delay data to produce the effect effect. These sounds are mixed by the mixer and output as sound through the D / A converter.

Figure 3.25 SCSP system configuration

● System specifications

The SCSP system specifications are shown in Table 3.9.

Table 3.9 SCSP system specifications
 No
 item
 specification
 remarks
 1
 Sampling frequency
・ 44.1KHz
 2
 Speech synthesis method
・ PCM, FM method
 3
 Number of audio processing slots
・ 32 slots
 Four
 Waveform data format
・ 8bit, 16bit format ・ 2'S Complement
 Five
 Various functions
・ Envelope ・ Loop processing ・ LFO
 6
 Effect of built-in DSP
・ Reverb, chorus, etc.
 7
 Other features
・ DMAC… 1ch
・ Timer ... 3ch
・ MIDI… IN / OUT 1 each
・ External digital audio input: 1 stereo system
 ● Function
 The main functions of SCSP are as follows.
 ● Effects
 Since the DSP of SCSP can create multiple sound fields, it is possible to set the sound field of BGM and the sound field of the game itself to be different.
 For example, in a racing game, you can apply a concert venue reverb for BGM and a tunnel reverb for the game at the same time.
 Figure 3.26 Tunnel and BGM reverb
 Since not only the audio signal from the sound source but also the audio signal from the CD is input to the DSP, it is possible to apply effects to the audio of the CD. In addition, since the output level of the CD can also be controlled via SCSP, it is possible to balance the audio signal of the sound source section with the CD, so the sound of the sound source section will not be obscured by the sound of the CD. ..
 ● Sound localization
 Since SCSP is equipped with a high-performance digital mixer, it is possible to control the localization of each sound in real time. Therefore, the sound effect can be output with the localization that matches the position of the character on the screen. This process can also be done by the DSP. In that case, more detailed localization settings can be made, so even if the character moves slowly, the sound localization can be moved smoothly. By adding reverb to this localization, it is possible to create a sense of depth (sense of distance).
 Figure 3.27 Example of use in a tennis game
 In addition to this, it is possible to express the size of the room, outside, and space depending on the type of reverb. In addition, the type of reverb itself includes halls, stages, rooms, iron plates, etc., and it is possible to set any state.
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★ HARDWARE Manual ★ Sega Saturn Overview Manual
 Copyright SEGA ENTERPRISES, LTD., 1997