SOUND is a BASIC command to make sounds.
|Availability||Present in all original versions of BBC BASIC.|
|Token (hex)|| |
SOUND calls OSWORD &07 to generate sounds. It is most
commonly used to generate sounds with the internal sound generator, but it
can also be used to create speech or MIDI sounds, as specified by the
Defined channel numbers
|&20xx||Watford Electronics Speech system|
|&FExx||MIDI control |
|&FFxx||Speech system |
Internal sound system
The channel number encodes &HSFC where:
- H: Hold 0 or 1
- S: Sync 0 to 15, 0 to 3 usually implemented
- F: Flush 0 or non-0 (usually 0 or 1)
- C: Channel 0 to 15, 0 to 3 usually implemented
The internal sound system implements 4 channels (1 on the Electron), but extensions can increase the number of supported channels. For example, the Electron Sound Expansion supports four channels, and MIDI redirection can support 16 channels treating each channel as a polyphonic note. Channel 0 is conventionally a 'noise' channel.
The volume, pitch and duration are 8-bit numbers with bit 8 and higher ignored.
Watford speach commands can be sent with SOUND &2000, which is usually coded as SOUND 8192.
Bit 0-7 of the channel number is ignored.
MIDI commands can be sent with SOUND &FEFF and SOUND &FEFE which are usually coded as SOUND -257 and SOUND -258.
- SOUND -257,Command,Note,Velocity - Send to current channel (channel=&FEFF)
- SOUND -258,Command,Note,Velocity - Send raw MIDI command (channel=&FEFE)
- SOUND -257 or -258,Control<0,num,num - MIDI system control
If Command is &0000-&007F it is a MIDI data byte and sent stright to the MIDI system unchanged. This allows extended sequences to be sent, such as MIDI System Exclusives.
If Command is &0080-&00FF it is a MIDI command byte. Command bytes &80-&EF are channel-specific commands. SOUND -258 uses them as supplied, SOUND -257 sends them to the current MIDI channel by adding the current channel to the bottom nybble. So, if the current MIDI channel is 4, SOUND -257,&80... will send to MIDI channel 4, and SOUND -257,&8F should send to MIDI channel 3. Some implementations do not correctly round the channel number within the nybble in the second example.
Note and Velocity are 7-bit numbers with bit 7 and higher ignored, other than MIDI command &Ex which can specify a 14-bit Note number.
The channel number indicates what to do with the command, the command is an 8-bit number with bit 8 and higher ignored.
- SOUND &FFFx,number,0,0 - speak from PHROM 15-x with word number. From a coding view this is usually written as SOUND -1,n,0,0 to SOUND -16,n,0,0.
- SOUND &FFBx,address,0,0 - speak from PHROM 15-x from the absolute address.
- SOUND &FF60,command,0,0 - start sending speech using phoneme 'command.
- SOUND &FF00,command,0,0 - continue sending speech using phoneme 'command.
SOUND &FF01-&FF7F actually send the bottom byte as the Speech command to use.
SOUND Channels -------------- %000H SSSS FFFF CCCC Internal sound system %0010 0000 xxxx xxxx Watford Electronics Speech %1111 1110 1111 111x MIDI control %1111 1111 xxxx xxxx Speech Sound system ------------ SOUND %000hssss:xxxfcccc, %xxxxxxxx:xxxvvvvv, %xxxxxxxx:pppppppp, %xxxxxxxx:dddddddd - Make sound Watford Speech -------------- SOUND %00100000:xxxxxxxx, %xxxxxxxx:wwwwwwww, %xxxxxxxx:llllllll, %xxxxxxxx:xxxxxxxx - Speak word MIDI ---- SOUND %11111110:xxxxcccc, %0xxxxxxx:0ddddddd, %xxxxxxxx:xxxxxxxx, %xxxxxxxx:xxxxxxxx - MIDI data SOUND %11111110:xxxxcccc, %0xxxxxxx:10dddddd, %xxxxxxxx:xnnnnnnn, %xxxxxxxx:xvvvvvvv - MIDI note SOUND %11111110:xxxxcccc, %0xxxxxxx:110ddddd, %xxxxxxxx:xnnnnnnn, %xxxxxxxx:xxxxxxxx - MIDI change SOUND %11111110:xxxxcccc, %0xxxxxxx:1110dddd, %xxvvvvvv:vvvvvvvv, %xxxxxxxx:x0000000 - MIDI bend SOUND %11111110:xxxxcccc, %0xxxxxxx:1110dddd, %xx000000:0vvvvvvv, %xxxxxxxx:xvvvvvvv - MIDI bend SOUND %11111110:xxxxcccc, %0xxxxxxx:1111dddd, %xxxxxxxx:xxxxxxxx, %xxxxxxxx:xxxxxxxx - MIDI system SOUND %11111110:1111111c, %1xxxxxxx:1111dddd, %xxxxxxxx:nnnnnnnn, %xxxxxxxx:xxxxxxxx - MIDI control \--\/--/ MIDI command if b15=0 and b7=0 Speech ------ SOUND %11111111:11xxrrrr, %xxxaaaaa:aaaaaaaa, %xxxxxxxx:xxxxxxxx, %xxxxxxxx:xxxxxxxx - Speak word SOUND %11111111:10xxrrrr, %xxaaaaaa:aaaaaaaa, %xxxxxxxx:xxxxxxxx, %xxxxxxxx:xxxxxxxx - Speak from address SOUND %11111111:0cccxxxx, %dddddddd:dddddddd, %xxxxxxxx:xxxxxxxx, %xxxxxxxx:xxxxxxxx - Speak data word SOUND %11111111:00000000, %dddddddd:dddddddd, %xxxxxxxx:xxxxxxxx, %xxxxxxxx:xxxxxxxx - Speak data word \--\/--/ if b7=0, if<>0, sent to Speech as command, normally use &FF60 for Speak External
In the original development of BBC BASIC, the sound command was
BEEP which can be seen from the token position for
SOUND, alphabetically with other keywords starting with 'B':
Originally: Became: D4: BEEP D4: SOUND D5: BPUT D5: BPUT D6: CALL D6: CALL D7: CHAIN D7: CHAIN etc.
- Watford Speech Synthesizer Manual
- *MIDI command
- Speech System User Guide
- Outline specification of the BASIC language interpreter, 1981
Jgharston 00:30, 2 January 2008 (UTC)