Block composition of 2.4 sound system
The flow of actual sound data when the sound instruction and the function are executed is more complex than a past system. Here, the part (especially, DSP/mixer control relation) not understood easily only from referring to the manual of each instruction is shown in figure and it explains.
The flow of the sound data roughly traces the route like figure and mixing is done finally by two stereo channels.
In the state that the DSP effector is not used, it is ..only changing the parameter of "72: direct data sending level" and "73: the direct data location" and "Mastering volume" only because of "Direct element" of figure it.. ..the sound... Mastering volume is set the default value by the VOLUME instruction, and when the DSP effector is not used, doesn't have the necessity for considering the mixer at all because the default value is set to the tone data side beforehand for the parameter of other direct elements.

The DSP effect module is detailed.
"DSP" Internal composition at mode
When PLAYINIT "DSP" is executed, DSP is initialized in the single effector mode. The input mixer uses only the channel "0".
Because it is default and "0", the effector can be used only by changing "71: the input mixture level" though it is connected when "70: the input selection" of the layer that the tone in which it wants to pass the effector rots by ten is set to "0" channel by the TPROP/DSP instruction (There is a tone to which the mixture level is set beforehand, too). Oppositely, please set "71: the input mixture level" to "0" for the tone in which it doesn't want to pass the effector. Please refer to the TPROP/DSP instruction for details. The output mixer uses only the channel "0~1" (Because the distortion is a monaural effector, only the channel "0" :).
The output mixer sets the channel "0" in default, and the channel "1" is shaken to Right, and the effect level is set to Left in the maximum. This setting can be changed later by "Ep: the effect bread" command of MML and "El: the effect level" command.
Attention
As for the distortion, the output level is growing because of the effector that distorts the sound by intention. Please adjust it by "El" command.

"DSPEXT" Internal composition at mode
When PLAYINIT "DSPEXT" is executed, DSP is initialized in the multi effector mode. The channel "0~2" can be chosen to be an input mixer according to the kind of the effector (0~2 corresponds to constant symbol @REV, @DEL, and @DST).
If "70: the input selection" of the layer to which the tone in which it wants to pass the effector is registered is set to "0~2" channel by the TPROP/DSP instruction, it becomes a reverberation when not especially selecting it though it is connected because it is default and "0".
The output mixer can be separately taken out according to the kind of the effector. The output of the reverberation is allocated and because "2~3" and the distortion are monaural effectors, the output of "0~1" and DeLay is allocated only in the channel "4". Each output mixer is shaken to Left and Right by default, and the effect level is set in the maximum. The operation after it sets it is the same as "DSP" mode.

About the mixer
The mixer parameter of a direct element is set to the tone data beforehand. When "DSP" option is specified by the PLAYINIT instruction, the mixer parameter of the effect element is initialized.
Moreover, please set it by "El" command of MML because the mixer parameter of the effect element is not a unit of the tone.
When the DSP effect is not used when this sound system is used, the mixer need not be actually considered. The digital mixer of Sega Saturn is composed of four parts of direct voice Coordination Division/DSP input Danchousab/DSP output Danchousab/final output Coordination Division in the block of each audio signal where the balance level/is adjusted.

Direct voice Coordination Division
The output of each slot is a mixer block where the route connected directly with digital analog converter is managed. The output level and the output balance of each slot can be controlled.
Attention
It adjusts it by the TPROP instruction.

DSP input Danchousab
The mixing to input the output of each slot to DSP is done. Actually, the audio signal is selected by "Input selection" of the layer data of each tone and the input level is adjusted by "Input mixture level". When it has two or more voices in mixing by "Input selection", balancing of each sound is necessary. Because DSP can be input by doing two or more slot outputs in mixing, the same effect can be processed to two or more voices like the reverberation of BGM.
Attention
It sets it by TPROP or the DSP instruction.

DSP output Danchousab
The voice on which effect is put by DSP is finally brought together in the stereo through the mixing processing. The output level and the output balance can be adjusted. As for the data brought together here, mixing is done with the direct voice element. p
Attention
It adjusts it by "El" and "Ep" commands of MML.

Collection steps output Coordination Division
The output level is adjusted bringing a direct element and the effect element of the voice together.
Attention
It adjusts it by the VOLUME instruction.

Relation between pronunciation slot and layer data
To the person who wants to operate the value of the SCSP(Saturn Custom Sound Processir) register directly
There are 32 slots in Sega Saturn, and 32 sound or less concurrence is enabled. When this sound system is used, the slot number need not be considered though the explanation of figure was written by the slot. This is because of being dynamically allocated in one layer one slot internally. Therefore, everything need not be searched for the address of the sound source register corresponding to the pronunciation slot number like operating a past sound source parameter, be read and written, be set to the layer data beforehand, and when the layer pronounces, be the allocation (As well as MIDI) to which slot.
The layer data is made beforehand when the frequency modulation oscillator parameter is set (the TARG instruction "FM" command), and it reads and writes it specifying the layer number by the TPROP instruction when the parameter is changed later in real time (layer indirect operation of the setting to the SCSP register not direct). The value of the register set by this method is forwarded to an actual SCSP register (The user need not consider which pronunciation slot to have been allocated) according to timing that the layer is pronounced (note and sound). Please refer to the TPROP instruction for details of the register item.

Priority level of direct bread
If "P (direct bread)" command of MML is executed, "73: the direct data location" that can be set by the TPROP instruction becomes invalid. The tone must change by "@" command of MML when you keep effective (program change). It is to be initialized by the tone change and note the setting of "P" command of MML (presence that blows "~ P: the auto bread" of the note on command), please when saying oppositely. Moreover, when the PLAYPAN instruction is executed, the direct bread by "P" command and the layer bread of the tone data become invalid. Next, the priority level of the bread specification command is arranged in high the order.

1. Sequence bread(PLAYPAN instruction)
2. MML bread(MML "P" command)
3. Layer bread(TPROP item number "73: Direct data location")
In any case, it is set to the mixer of the location of the direct data of figure introduced first (It is not because a set place is independent).
Attention
When monaural has been selected on the user setting screen, the effect doesn't become visible.