SOUND

What is the setting of STEREO / MONO on CD-DA?

Q)

How to switch STEREO / MONORAL of CDDA sound Initially, I thought that I should change the stereo / monaural setting of BOOT-ROM, but according to the software creation guideline, the setting of BOOT-ROM prohibits rewriting from the application. I don't know how to do it.

There is a stereo / monaural switch in the sound driver, but it seems to be the setting for PCM vocalization, so it is different from the information I want this time.

A)

The sound of CDDA can also be set with the stereo / monaural switching bit of the sound driver.

The SMPC I / F library is used to obtain the multiplayer status (stereo / monaural).

It doesn't work when SND_Init is set to slInitSound.

Q)

When I changed from SND_Init to slInitSound, there was no sound.
Isn't both functions just activating the sound CPU by transferring the driver and map data?

A)

wrong. It is true that both functions transfer the driver and the map and activate the 68000, but the other function of each function is to initialize the shared area.

SND_Init initializes the shared variables used by the SND_ * function, and slInitSound initializes the part of the SGL system variable area used by the sound, so when using such a sound function, look at the uninitialized data. Of course, there is no sound because it is operated.

These two function groups cannot be used at the same time, but if you use the SND_ * function in Cinepak etc., but use slSnd * in the main program, you can use it by performing slInitSound before using the slSnd * function. Can be done.
Of course, the reverse is also true.

How to set volume / Pan without using Sound I / F library in SBL?

Q)

How to set the volume / Pan without using the sound I / F library (SND_SetCdDaLev / SND_SetCdDaPan) in SBL

A)

There is no other way to work at the library level.
Another method is to do it via a sound driver.
You can operate CD-DA Level and CD-DA Pan as sound control commands.
See the SATURN Sound Driver System Interface Manual for this.
In addition, SND_SetCdDaLev / SND_SetCdDaPan also performs the same processing after all.

I want to PAN the sequence, but the sound is in the middle.

Q)

I tried to pan the sequence but it sounds in the middle. The maximum (1F) is set for L, and even if you check the command history (0E, 01, ...), the pan command is sent properly.

A)

First, find out if you are using effects (DSP) in your sequence. Also, if you shake the pan too much to the left and right, you may hear the phenomenon in the middle. In that case, try adjusting the value to be set smaller.

How do you calculate the PCM playback pitch?

Q)

I don't know how to calculate the value specified for the PCM playback pitch.

A)

The calculation of the playback pitch is as follows.
Assuming that the playback frequency is Fn

 ((s ^ -OCT x 1024 x Fn) / 44.1 --1024) x OCT x 2048

It will be. However, the value of OCT is

 5.5125KHz ~ 11.025KHz -3
11.025KHz ~ 22.05KHz -2
22.05KHz ~ 44.1KHz -1
44.1KHz ~ 88.2KHz 0
88.2KHz ~ 1

is. For details, refer to PROGRAMMERS GUIDE VOL.1 Sound Embedded Manual 6.4.5 “Support for playback frequencies other than 44.1kHz”.

I want to bring the data to the 68000 side when playing a PCM stream.

Q)

Do I have to put all the data to "play PCM stream" in the main memory of SH2?
Isn't it possible to pull the data to the main before the next transfer to the 68000?

A)

Since this is a specification of the stream library, it is not possible to bring stream data directly to the 68000 side.

How to apply effects to PCM stream playback

Q)

I want to apply the effect of the built-in DSP to the PCM stream playback, but the parameter is fixed to 0 initialization and it seems that it cannot be changed. Is there any support in the library that can change the send level of the effect? ??

The sound driver seems to be able to change the effect parameters such as volume, localization, and effect send level, but the library commented that "DSP is not used" and was fixed at 0.

A)

The only way is to issue the command directly to the sound driver.

Slot is fixed when playing PCM stream

Q)

I checked the slot status to check the number of pronunciations, but it seems that the PCM stream occupies slots 3 and 4.
The sound driver side should have a dynamic voice allocation, but if it is left as it is, if some instruments of BGM are playing in slot 3 and PCM is played, the sound will be muted.
Is there a way around this?

A)

If you bring the PCM stream to No. 4 as much as possible, the songs that came in up to No. 3 will not disappear, so please handle it.

Direct MIDI reduces volume

Q)

When SE is played continuously by direct MIDI, the volume (Verocity) suddenly decreases. I have issued the note-off command properly, but is there any other cause?

A)

Is the note-off properly one-to-one correspondence and is the command issued each time? Also, if the parameters specified at that time are not the same as those of the note-on (Verocity setting etc.), the above phenomenon may occur. not.
Other than that, there is no particular cause.

About the floating point specification of the delay buffer.

Q)

Please tell me the floating point format of one data (16bit) of the data in the delay buffer.
Also

LDI MEMSXX, MR [Table + ADREG / NF]

When data is loaded with non-floating specification like, does it enter the upper 16 bits of the 24 bits of the MEMSXX register? Does it enter the lower 16 bits?

A)

Floating point formats cannot be taught due to a nondisclosure agreement with Yamaha.
The upper 16 bits of the register are entered, and 0 is entered in the rest.