|
|
| Line 5: |
Line 5: |
| | |+ SOUND | | |+ SOUND |
| | | Availability | | | Availability |
| − | | colspan="2" | Present in all original versions of BBC BASIC. | + | | colspan="2" | Present in all versions of BBC BASIC. |
| | |- style="vertical-align:top" | | |- style="vertical-align:top" |
| | | [[BASIC metasyntax|Syntax]] | | | [[BASIC metasyntax|Syntax]] |
| Line 38: |
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| | |} | | |} |
| | | | |
| − | == Implementation == | + | == Specification == |
| | === Internal sound system === | | === Internal sound system === |
| | <code>SOUND &0xxx,volume,pitch,duration</code> | | <code>SOUND &0xxx,volume,pitch,duration</code> |
| | | | |
| − | <code>SOUND &1xxx,volume,pitch,duration</code> | + | <code>SOUND &1xxx,ignored,ignored,ignored</code> |
| | | | |
| | The channel number encodes &HSFC where: | | The channel number encodes &HSFC where: |
| | * H: Hold 0 or 1 | | * H: Hold 0 or 1 |
| | * S: Sync 0 to 15, 0 to 3 usually implemented | | * S: Sync 0 to 15, 0 to 3 usually implemented |
| − | * F: Flush 0 or non-0 (usually 0 or 1) | + | * F: Flush 0 or 1, 2-15 reserved |
| | * C: Channel 0 to 15, 0 to 3 usually implemented | | * C: Channel 0 to 15, 0 to 3 usually implemented |
| | | | |
| Line 55: |
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| | channel as a polyphonic note. Channel 0 is conventionally a 'noise' channel. | | 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.
| + | Channel parameter |
| | + | ----------------- |
| | + | SOUND &xxxC,vol,pitch,dur play a note on channel C |
| | + | |
| | + | SOUND &xx0x,vol,pitch,dur don't flush channel |
| | + | SOUND &xx1x,vol,pitch,dur flush channel before playing note |
| | + | SOUND &xx2x,vol,pitch,dur \ |
| | + | to } future expansion |
| | + | SOUND &xxFx,vol,pitch,dur / |
| | + | |
| | + | SOUND &xSxx,vol,pitch,dur synchronise with S other channels |
| | + | |
| | + | SOUND &0xxx,vol,pitch,dur play specified note |
| | + | SOUND &1xxx,ign,ign,ign continue the current note on the channel |
| | + | |
| | + | Volume parameter |
| | + | ---------------- |
| | + | SOUND chn,-32768,pitch,dur \ |
| | + | to } future expansion |
| | + | SOUND chn,-16 ,pitch,dur / |
| | + | SOUND chn,-15 ,pitch,dur \ |
| | + | to } play a note with an envelope |
| | + | SOUND chn, -1 ,pitch,dur / |
| | + | SOUND chn, 0 ,pitch,dur stop note (zero volume) |
| | + | SOUND chn, 1 ,pitch,dur \ |
| | + | to } play a note with an envelope |
| | + | SOUND chn,16 ,pitch,dur / |
| | + | SOUND chn,17 ,pitch,dur \ |
| | + | to } future expansion |
| | + | SOUND chn,32767 ,pitch,dur / |
| | + | |
| | + | Pitch parameter |
| | + | --------------- |
| | + | SOUND chn,vol,&0000,dur \ |
| | + | to } 8-bit pitch &xx00 to &xxFF |
| | + | SOUND chn,vol,&00FF,dur / |
| | + | SOUND chn,vol,&0100,dur \ |
| | + | to } 8-bit pitch &xx00 to &xxFF (see notes) |
| | + | SOUND chn,vol,&03FF,dur / |
| | + | SOUND chn,vol,&x400,dur \ |
| | + | to } 15-bit pitch &4000+&ORRR, O=octave, RRR=residual, &4000=middle C (expansion) |
| | + | SOUND chn,vol,&7FFF,dur / |
| | + | SOUND chn,vol,&8000,dur \ |
| | + | to } 15-bit pitch change &C000+delta (expansion) |
| | + | SOUND chn,vol,&FFFF,dur / |
| | + | |
| | + | 8-bit pitches are 48 units per octave, with middle C=101 (see notes) |
| | + | 15-bit pitches are &1000 units per octave, with middle C=&4000 |
| | + | |
| | + | Duration parameter |
| | + | ------------------ |
| | + | SOUND chn,vol,pitch,-32768 \ |
| | + | to } future expansion |
| | + | SOUND chn,vol,pitch,-2 / |
| | + | SOUND chn,vol,pitch,-1 play note forever (until flushed) |
| | + | SOUND chn,vol,pitch,0 \ |
| | + | to } play for specified 1/20th second |
| | + | SOUND chn,vol,pitch,32767 / |
| | | | |
| | === Watford Speech === | | === Watford Speech === |
| Line 95: |
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| | | | |
| | SOUND &FF01-&FF7F actually send the bottom byte as the Speech command to use. | | SOUND &FF01-&FF7F actually send the bottom byte as the Speech command to use. |
| − |
| |
| − | === Summary ===
| |
| − | 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 %0000ssss:xxxfcccc, %xxxxxxxx:xxxvvvvv, %xxxxxxxx:pppppppp, %xxxxxxxx:dddddddd - Make sound
| |
| − | SOUND %0001ssss:xxxfcccc, %xxxxxxxx:xxxxxxxx, %xxxxxxxx:xxxxxxxx, %xxxxxxxx:xxxxxxxx - Hold current note
| |
| − |
| |
| − | Watford Speech
| |
| − | --------------
| |
| − | SOUND %00100000:xxxxxxxx, %xxxxxxxx:wwwwwwww, %xxxxxxxx:llllllll, %xxxxxxxx:xxxxxxxx - Speak word
| |
| − |
| |
| − | MIDI
| |
| − | ----
| |
| − | SOUND %11111110:1111111c, %0xxxxxxx:0ddddddd, %xxxxxxxx:xxxxxxxx, %xxxxxxxx:xxxxxxxx - MIDI data
| |
| − | SOUND %11111110:1111111c, %0xxxxxxx:10dddddd, %xxxxxxxx:xnnnnnnn, %xxxxxxxx:xvvvvvvv - MIDI note
| |
| − | SOUND %11111110:1111111c, %0xxxxxxx:110ddddd, %xxxxxxxx:xnnnnnnn, %xxxxxxxx:xxxxxxxx - MIDI change
| |
| − | SOUND %11111110:1111111c, %0xxxxxxx:1110dddd, %xxvvvvvv:vvvvvvvv, %xxxxxxxx:x0000000 - MIDI bend
| |
| − | SOUND %11111110:1111111c, %0xxxxxxx:1110dddd, %xx000000:0vvvvvvv, %xxxxxxxx:xvvvvvvv - MIDI bend
| |
| − | SOUND %11111110:1111111c, %0xxxxxxx:1111dddd, %xxxxxxxx:xxxxxxxx, %xxxxxxxx:xxxxxxxx - MIDI system
| |
| − | SOUND %11111110:1111111c, %1xxxxxxx:1111dddd, %xxxxxxxx:nnnnnnnn, %xxxxxxxx:xxxxxxxx - MIDI control
| |
| − |
| |
| − | 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
| |
| | | | |
| | == Trivia == | | == Trivia == |
| Line 140: |
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| | D7: CHAIN D7: CHAIN | | D7: CHAIN D7: CHAIN |
| | etc. | | etc. |
| | + | |
| | + | == See also == |
| | + | See OSWORD 7 for implementation |
| | | | |
| | == References == | | == References == |
| Line 145: |
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| | | | |
| | [[User:Jgharston|Jgharston]] 00:30, 2 January 2008 (UTC) | | [[User:Jgharston|Jgharston]] 00:30, 2 January 2008 (UTC) |
| − | <!--
| + | [[User:Jgharston|Jgharston]] ([[User talk:Jgharston|talk]]) 23:58, 7 March 2020 (CET) |
| − | SOUND
| |
| − | | |
| − | Purpose
| |
| − | | |
| − | This statement is used to make the computer generate sounds using the
| |
| − | internal loudspeaker. The sound generator is capable of making four sounds
| |
| − | at once. Each of the four sound channels can generate one note. The keyword
| |
| − | SOUND must be followed by four numbers which specify
| |
| − | | |
| − | * which sound channel is to be used
| |
| − | * the loudness of the note (or the envelope number)
| |
| − | * the pitch of the note
| |
| − | * how long the note is to last
| |
| − | | |
| − | For example:
| |
| − | | |
| − | SOUND 1,-15,53,20
| |
| − | | |
| − | will play a note on sound channel 1, with a loudness of -15 (maximum
| |
| − | volume). A pitch value of 53 gives middle C and a duration of 20 will make
| |
| − | the note last for 1 second.
| |
| − | | |
| − | SOUND C,A,P,D
| |
| − | | |
| − | The channel number (C) can be 0,1,2, or 3. Channel 0 is a special channel
| |
| − | that can produce various noises, whereas channels 1, 2 and 3 are used to
| |
| − | produce single notes. Other values of C (the channel number) produce special
| |
| − | effects which are explained further on.
| |
| − | | |
| − | The amplitude or loudness (A) can have any whole number value between -15
| |
| − | and 4. Values -15 to 0 produce notes of fixed loudness throughout the whole
| |
| − | note. A value of -15 is the loudest, -7 is half volume and 0 produces
| |
| − | silence. Values of 1 to 4 enable the amplitude to be controlled while the
| |
| − | note is playing. When you play a note on the piano the sound gradually fades
| |
| − | away. Effects like this are selected by using one of the 4 user-defined
| |
| − | envelopes which are selected by setting A to be 1,2,3 or 4. Envelopes are
| |
| − | explained on pages 182 and 244.
| |
| − | | |
| − | The pitch (P) is used to set the pitch or frequency of the note. The pitch
| |
| − | can have any value between 0 and 255. The note A above middle C is selected
| |
| − | with a value of 89. The table on page 181 shows the value of P needed to
| |
| − | produce a particular note. You will see that to go up an octave P is
| |
| − | increased by 48 and to go up a perfect 5th P must be increased by 28.
| |
| − | | |
| − | Increasing the value of P by one will increase the note produced by a
| |
| − | quarter of a semi-tone.
| |
| − | | |
| − | To play the chord of C major which consists of the notes C, E and G for 2
| |
| − | seconds you could enter
| |
| − | | |
| − | 100 SOUND 1,-15,53,40
| |
| − | | |
| − | 110 SOUND 2,-15,69,40
| |
| − | | |
| − | 120 SOUND 3,-15,81,40
| |
| − | | |
| − | Whereas to play a number of notes in succession you would enter
| |
| − | | |
| − | 100 SOUND l,-15,97,10
| |
| − | | |
| − | 110 SOUND 1,-15,105,10
| |
| − | | |
| − | 120 SOUND 1,-15,89,10
| |
| − | | |
| − | 130 SOUND 1,-15,41,10
| |
| − | | |
| − | 140 SOUND 1,-15,69,20
| |
| − | | |
| − | which plays a well-known film theme.
| |
| − | | |
| − | The duration (D) can have any value between -1 and 254. Values in the range
| |
| − | 0 to 254 give a note duration of that number of twentieths of a second. Thus
| |
| − | if D=40 the note will last for 2 seconds. Setting D=-1 means that the note
| |
| − | will continue to sound until you actually take steps to stop it. You can
| |
| − | either press the ESCAPE key or stop it by sending another note, to the same
| |
| − | channel, which has "Flush Control" set to 1 - see page 353 later in this
| |
| − | section.
| |
| − | | |
| − | As was mentioned earlier in this section, channel number 0 produces "noises"
| |
| − | rather than notes and the value of P in the statement
| |
| − | | |
| − | SOUND 0,A,P,D
| |
| − | | |
| − | has a different effect from that described for channels 1, 2 and 3. Here is
| |
| − | a summary of the effects of different values of P on the noise channel:
| |
| − | | |
| − | P / Effect
| |
| − | | |
| − | 0 / High frequency periodic noise
| |
| − | | |
| − | 1 / Medium frequency periodic noise
| |
| − | | |
| − | 2 / Low frequency periodic noise
| |
| − | | |
| − | 3 / Periodic noise of frequency determined by the pitch setting of channel 1
| |
| − | | |
| − | 4 / High frequency "white" noise
| |
| − | | |
| − | 5 / Medium frequcy "white" noise
| |
| − | | |
| − | 6 / Low frequency "white" noise
| |
| − | | |
| − | 7 / Noise of frequency determined (continuously) by the pitch setting of channel 1
| |
| − | | |
| − | Values of P between 0 and 3 produce a rather rasping, harsh note. With P set
| |
| − | to 4 the noise is not unlike that produced by a radio when it is not tuned
| |
| − | to a station - sort of "shssh" effect. P=6 sounds like the interference
| |
| − | found on bad telephone call.
| |
| − | | |
| − | When P is set to 3 or 7 then the frequency of the noise is controlled by the
| |
| − | pitch setting of sound channel number 1. If the pitch of channel 1 is
| |
| − | changed while channel 0 is generating noise then the pitch of the noise will
| |
| − | also change. The program below generates a noise on channel 0 and varies the
| |
| − | pitch of the noise by changing the pitch of channel 1. Notice that the
| |
| − | amplitude of channel one is very low (-1) so you will hardly hear it - but
| |
| − | you will hear the noise on channel 0.
| |
| − | | |
| − | 100 SOUND 0,-15,7,150
| |
| − | | |
| − | 110 FOR P= 100 TO 250
| |
| − | | |
| − | 120 SOUND 1,-1,P,1
| |
| − | | |
| − | 130 NEXT P
| |
| − | | |
| − | Notice that we have not yet described how sounds can be affected by a
| |
| − | superimposed envelope. An envelope can affect both the pitch and amplitude
| |
| − | of a note as it is playing. Thus the statement
| |
| − | | |
| − | SOUND 1,-15,255,255
| |
| − | | |
| − | merely plays a continuous loud note, whereas
| |
| − | | |
| − | ENVELOPE 1,1,-26,-36,-45,255, 255,255,127,0,0,-127,126,0
| |
| − | | |
| − | SOUND 1,1,255,255
| |
| − | | |
| − | produces a complex sound controlled largely by the envelope.
| |
| − | | |
| − | See the keyword ENVELOPE for more details.
| |
| − | | |
| − | As mentioned briefly at the start of the description of the SOUND statement,
| |
| − | the channel number, C can be given values other than 0, 1, 2 and 3. You need
| |
| − | not understand exactly why the following works to use it!
| |
| − | | |
| − | For C one can write a four figure hexadecimal number to achieve certain
| |
| − | effects - for example:
| |
| − | | |
| − | SOUND &1213,-15,53,40
| |
| − | | |
| − | The first parameter in the above example has the value &1213. The ampersand
| |
| − | (&) indicates to the computer that the number is to be treated as a
| |
| − | hexadecimal number. The four figures which follow the ampersand each control
| |
| − | one feature. In this new expanded form the SOUND statement looks like
| |
| − | | |
| − | SOUND &HSFC,A,P,D
| |
| − | | |
| − | and the functions H,S,F and C will be explained in turn. In essence these
| |
| − | numbers enable one to synchronize notes so that one can play chords
| |
| − | effectively.
| |
| − | | |
| − | The first number (H) can have the value 0 or 1. If H= 1 then instead of
| |
| − | playing a new note on the selected channel, the previous note on that
| |
| − | channel is allowed to continue. If a note were gently dying away then it
| |
| − | might be abruptly terminated when its time was up. Setting H=1 allows the
| |
| − | note to continue instead of playing a new note. If H=1 then the note defined
| |
| − | by the rest of the SOUND statement is ignored.
| |
| − | | |
| − | The second number (S) is used to synchronize the playing of a number of
| |
| − | notes. If S= 0 then the notes are played as soon as the last note on the
| |
| − | selected channel has completed. (There is a slight simplification here;
| |
| − | "completed" means "has reached the start of the release phase".) The user is
| |
| − | referred to the keyword ENVELOPE for relevant detail.
| |
| − | | |
| − | A non-zero value of S indicates to the computer that this note is not to be
| |
| − | played until you have a corresponding note on another channel ready to be
| |
| − | played. A value of S=1 implies that there is one other note in the group.
| |
| − | S=2 implies two other notes (i.e. a total of 3). If a note was sent to
| |
| − | channel one with S set to 1 then it would not be played until a note was
| |
| − | ready on another channel which also had S set to 1. For example:
| |
| − | | |
| − | 110 SOUND &101,-15,50,200
| |
| − | | |
| − | 110 SOUND 2,-15,200,100
| |
| − | | |
| − | 120 SOUND &102,-15,100,200
| |
| − | | |
| − | When this program is run the note at line 100 will not play until channel 2
| |
| − | is free. Line 110 sounds a note immediately on channel 2 - and for 5 seconds
| |
| − | (duration 100). When that note has completed then both the notes from lines
| |
| − | 100 and 120 will sound together.
| |
| − | | |
| − | The third number (F) can have the value 0 or 1. If it is set to 1 then the
| |
| − | sound statement in which it occurs flushes (throws away) any other notes
| |
| − | waiting in the queue for a particular channel. It also stops whatever note
| |
| − | is being generated on that channel at present. The sound statement in which
| |
| − | F=1 then plays its note. Setting F behaves like an "over-ride". For example:
| |
| − | | |
| − | 20 SOUND 2,-15,200,100
| |
| − | | |
| − | 25 FOR X=1 TO 500:NEXT X
| |
| − | | |
| − | 30 SOUND &12,-15,100,200
| |
| − | | |
| − | In the above situation line 20 will start a sound on channel2 but this will
| |
| − | be stopped almost immediately by line 30 which will generate a lower and
| |
| − | longer note on channel 2. Line 25 just gives a short delay.
| |
| − | | |
| − | Setting F=1 provides an easy way of stopping an everlasting note! Thus SOUND
| |
| − | &13,0,0,1 stops the current note on channel 3 and instead plays one at zero
| |
| − | loudness and of minimum length. This will stop channel 3 immediately.
| |
| − | | |
| − | The last number (C) is the channel number described earlier.
| |
| − | | |
| − | Description
| |
| − | | |
| − | The sound generator has four separately-controlled synthesis channels. Each
| |
| − | can sound at one of 16 amplitudes, including 'off'. The audio output is the
| |
| − | sum of the channel outputs. Channels 1 - 3 each generate a squarewave with
| |
| − | programmable frequency. Channel 0 can produce noise (unpitched sound of
| |
| − | psuedo-random structure) or a pulse waveform. The frequency of the pulsewave
| |
| − | or period of the noise can be set to one of the three fixed options, or to
| |
| − | the frequency of channel.
| |
| − | | |
| − | The BASIC program generates each sound by initiating one or more 'requests',
| |
| − | each of which may take the form of a musical note or a single effect and is
| |
| − | directed to a specific channel. If the destination channel is idle when a
| |
| − | request requires it, the sound starts playing immediately. If a previous
| |
| − | request is still being handled the new one is placed on a queue, where it
| |
| − | waits until the current event is over (or past a critical stage - see
| |
| − | ENVELOPE). If the queue is full, the program waits. Separate queues are
| |
| − | provided for the four channels, each of which can hold up to four requests,
| |
| − | not counting the one currently being executed. The program can look at the
| |
| − | state of any queue and flush any queue, but cannot find out or alter the
| |
| − | state of the current event, except for flushing the whole queue.
| |
| − | | |
| − | The SOUND keyword is followed by four parameters, the first of which
| |
| − | consists of 4 hexadecimal digits. Thus
| |
| − | | |
| − | SOUND &HSFC,A,P,D
| |
| − | | |
| − | Range Function
| |
| − | | |
| − | H 0 or 1 Continuation
| |
| − | S 0 to 3 Synchronization
| |
| − | F 0 or 1 Flush
| |
| − | C 0 to 3 Channel number
| |
| − | A -15 to 4 Amplitude or envelope number
| |
| − | P 0 to 255 Pitch
| |
| − | D 1 to 255 Duration
| |
| − | | |
| − | The 'H' parameter allows the previous event on that channel to continue, and
| |
| − | if this is 1, the amplitude and pitch parameters of SOUND have no effect.
| |
| − | Because the dummy note is queued in the normal way, it can be used to ensure
| |
| − | that the release segment of a sound, which occurs after the duration is over
| |
| − | and would otherwise be truncated by the next sounding event on the same
| |
| − | channel, is allowed to complete.
| |
| − | | |
| − | The 'S' parameter allows requests to be queued separately and then executed
| |
| − | at the same instant, for chords and multiple voice effects. The value
| |
| − | initially determines the number of other channels that must receive requests
| |
| − | with the same value of 's', before the group will play. For example, each
| |
| − | note of a three-note chord would be generated by a SOUND with the value of 2
| |
| − | for 's'. The system will read the value of 's' from the first one and then
| |
| − | wait for 2 more requests with 2 as the value of 's' before playing the
| |
| − | complete chord. Single requests use 0 for 's' so they play as soon as they
| |
| − | reach the end of the channel queue.
| |
| − | | |
| − | The parameter 'F' will normally be zero, causing the request to be queued.
| |
| − | If it is 1, the channel queue will be flushed first, so the request will
| |
| − | sound immediately.
| |
| − | | |
| − | The parameter 'C' determines the number of the sound channel to be used.
| |
| − | | |
| − | The 'A' parameter controls the amplitude of the sound and can be used in two
| |
| − | ways. Positive values up to 4 select the envelope (1 to 4) to be used. If
| |
| − | the RS423 and cassette output buffers are unused then envelope numbers up to
| |
| − | 16 may be defined and used. Zero and negative integers up to -15 directly
| |
| − | set the amplitude of the sound, which is then fixed at this value for the
| |
| − | duration of the note. -15 corresponds to the loudest, and 0 is 'off'. The
| |
| − | 'P' parameter determines the pitch of the note. It can take values from 0 to
| |
| − | 255.
| |
| − | | |
| − | The 'D' parameter determines the total duration of sounds who amplitude is
| |
| − | determined explicitly by a negative or zero value of 'A' parameter. The
| |
| − | duration is given in twentieths of a second. If an envelope has been
| |
| − | selected, by a positive value of 'A', then the duration 'D' determines the
| |
| − | total of the attack, decay and sustain periods - but not of the release
| |
| − | phase. Syntax
| |
| − | | |
| − | SOUND <numeric>,<numeric>,<numeric>,<numeric>
| |
| − | | |
| − | -->
| |
SOUND is a BASIC command to make sounds.
SOUND
| Availability
|
Present in all versions of BBC BASIC.
|
| Syntax
|
SOUND <numeric>,<numeric>,<numeric>,<numeric>
|
| Token (hex)
|
D4 (command)
|
| Description
|
Generates sounds.
|
Description
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
channel parameter.
Defined channel numbers
| &0xxx |
Sound generator
|
| &1xxx |
Sound generator
|
| &20xx |
Watford Electronics Speech system[1]
|
| |
|
| &FExx |
MIDI control [2]
|
| &FFxx |
Speech system [3]
|
Specification
Internal sound system
SOUND &0xxx,volume,pitch,duration
SOUND &1xxx,ignored,ignored,ignored
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 1, 2-15 reserved
- 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.
Channel parameter
-----------------
SOUND &xxxC,vol,pitch,dur play a note on channel C
SOUND &xx0x,vol,pitch,dur don't flush channel
SOUND &xx1x,vol,pitch,dur flush channel before playing note
SOUND &xx2x,vol,pitch,dur \
to } future expansion
SOUND &xxFx,vol,pitch,dur /
SOUND &xSxx,vol,pitch,dur synchronise with S other channels
SOUND &0xxx,vol,pitch,dur play specified note
SOUND &1xxx,ign,ign,ign continue the current note on the channel
Volume parameter
----------------
SOUND chn,-32768,pitch,dur \
to } future expansion
SOUND chn,-16 ,pitch,dur /
SOUND chn,-15 ,pitch,dur \
to } play a note with an envelope
SOUND chn, -1 ,pitch,dur /
SOUND chn, 0 ,pitch,dur stop note (zero volume)
SOUND chn, 1 ,pitch,dur \
to } play a note with an envelope
SOUND chn,16 ,pitch,dur /
SOUND chn,17 ,pitch,dur \
to } future expansion
SOUND chn,32767 ,pitch,dur /
Pitch parameter
---------------
SOUND chn,vol,&0000,dur \
to } 8-bit pitch &xx00 to &xxFF
SOUND chn,vol,&00FF,dur /
SOUND chn,vol,&0100,dur \
to } 8-bit pitch &xx00 to &xxFF (see notes)
SOUND chn,vol,&03FF,dur /
SOUND chn,vol,&x400,dur \
to } 15-bit pitch &4000+&ORRR, O=octave, RRR=residual, &4000=middle C (expansion)
SOUND chn,vol,&7FFF,dur /
SOUND chn,vol,&8000,dur \
to } 15-bit pitch change &C000+delta (expansion)
SOUND chn,vol,&FFFF,dur /
8-bit pitches are 48 units per octave, with middle C=101 (see notes)
15-bit pitches are &1000 units per octave, with middle C=&4000
Duration parameter
------------------
SOUND chn,vol,pitch,-32768 \
to } future expansion
SOUND chn,vol,pitch,-2 /
SOUND chn,vol,pitch,-1 play note forever (until flushed)
SOUND chn,vol,pitch,0 \
to } play for specified 1/20th second
SOUND chn,vol,pitch,32767 /
Watford Speech
SOUND &20xx,word,library,0
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 control
SOUND &FExx,command,note,velocity
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.
Speech system
SOUND &FFxx,command,0,0
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.
Trivia
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'[4]:
Originally: Became:
D4: BEEP D4: SOUND
D5: BPUT D5: BPUT
D6: CALL D6: CALL
D7: CHAIN D7: CHAIN
etc.
See also
See OSWORD 7 for implementation
References
Jgharston 00:30, 2 January 2008 (UTC)
Jgharston (talk) 23:58, 7 March 2020 (CET)
