Audio

Background music, sound effects and digital samples, all from the AUDIO\ folder. Everything here is optional - a game with no AUDIO\ folder builds and plays fine.

Music and effects are selected in your game with the SFX condact - the tables below list every sub-command and what it does on this target.

DAAD Ready's manual lists, in its Appendix D, symbolic names for the sub-command argument of SFX (PLAYSFX, PLAYDRO, and so on). The bundled ndrc compiler predefines every one of them, and a DSF written with the symbolic form compiles byte-identical to the same DSF written with the raw number - use whichever reads better.

Typo warning: the DAAD Ready manual's own Appendix D table names value 10 FPLAYFLIL. That is a documentation typo - FPLAYFLIL does not compile. The compiler defines PLAYFLI (9) and PLAYFLIL (10).

Sample numbers 1-254 may resolve to a WAV or fall back to an AY effect; 255 is reserved and always plays from the AY effects bank.

These six are a NextDAAD extension - they are not in DAAD Ready's Appendix D and the compiler predefines no symbolic names for them, so write the raw number. They let a game reserve one of the two sample channels for an effect rather than letting sub 1/2 pick automatically. See Two sample channels below for the full explanation, including what a reservation does and does not survive.

Compose in Arkos Tracker 3 and drop the .aks files into AUDIO\:

• <GAME>.aks - your theme. It plays automatically at boot, and SFX 255 6 (once) or SFX 255 7 (looped) plays it again from anywhere in the game.
• NNN.aks - numbered songs, played by SFX n 6 (once) or SFX n 7 (looped).
• STREAM_NNN.aks - a song too big for the song slot, streamed from the SD card instead. Selected exactly the same way, with SFX n 6 / SFX n 7.

SFX n 8 stops music of either kind.

Compose for three PSGs - nine channels. The Next's Turbo Sound has three AY chips, and the resident song player is built for exactly that shape. A .aks written for one or two PSGs converts without complaint and then does not play at all: the interpreter checks the channel count as it loads and refuses anything but nine, so the SFX that selects it is silently a no-op. Nothing in the build catches this for you. Set the song to 3 PSGs in Arkos Tracker and leave the channels you do not want empty - unused channels cost nothing and stay silent. (A streamed STREAM_NNN.aks is not restricted this way; the rule is the resident player's.)

The song slot is 10208 bytes, and a lot of real multi-channel tunes do not fit it. If the build stops with over the 10208 song limit, you have two choices: shorten the tune or reduce its channels, or rename the source to STREAM_NNN.aks and let it stream. Streamed songs have no fixed slot size - they are bounded only by free memory - at the cost of reading from the card while they play. Streaming needs Arkos Tracker 3's SongToYm.exe installed; the rest of the conversion is automatic.

Build your effects as a single Arkos sound-effects bank named <GAME>_FX.aks. Effects from it play with SFX n 1 (once) or SFX n 2 (looped), and SFX n 5 stops whatever effect is sounding.

The effects bank has 2048 bytes to fit into. If it comes out larger, or the effects tool is not installed, the build warns and carries on without it - your game still builds and plays, just silently where the effects would have been.

Drop 8-bit WAV files into AUDIO\ named by number - 001.wav, 002.wav - and they are copied to the release untouched. Play one with SFX n 1 (once) or SFX n 2 (looped), the same sub-commands the AY effects bank uses.

You supply the file in the right format; nothing converts it for you. It must be:

• PCM, mono, 8-bit unsigned,
• sampled between 3500 and 20000 Hz.

It plays back at whatever rate its own header declares - there is no resampling - so pick the rate when you export. 15625 Hz is the recommended rate: it divides the hardware's own timing clock exactly on six of the eight video modes, so on those modes the sample plays at exactly the authored pitch, with no rounding at all. 16000 Hz - the rate most existing NextDAAD samples already use - stays fully supported: the hardware's own clock varies by video mode and 16000 rarely divides it exactly, so it plays a little sharp on most modes, up to about 0.7% in the worst case - inaudible in a game sound effect. Nothing about an existing WAV needs to change; 15625 Hz is only worth picking for new samples where you want the theoretical best case.

Samples and AY effects share one set of numbers. SFX n 1 looks for NNN.WAV first and falls back to the effects bank if there is no such file, so a sample and an AY effect cannot both use number 7. Numbers 1 to 254 work either way; 255 always plays from the AY bank.

Samples play on either of two independent hardware channels, mixed together in the output and both centred, so two effects can sound at once. SFX n 1 and SFX n 2 choose a channel for you automatically:

• if a channel that is not reserved (see below) is already holding number n from a previous play, it plays there again - even if that channel is still playing it, in which case the effect simply restarts in place rather than a second copy starting elsewhere;
• otherwise, an idle channel that is not reserved takes it;
• if both channels are busy, one is taken over: a channel currently playing a one-shot effect is taken in preference to one playing a loop, and between two one-shots the older one goes. A reserved channel (see below) is never taken over, playing or not;
• if both channels are reserved - playing or not - the new effect is simply dropped: nothing plays, and nothing queues.

Reserve a channel for an effect with these four sub-commands, so nothing else can take it from under you while you need it there. Each always takes its channel outright, stopping whatever was playing there before, reserved or not:

A reservation lasts until you release it with 15, 16, or SFX n 5 below - including if the sample failed to load. A NNN.WAV that turns out to be missing still reserves the channel it was asked for, because the reservation is made before the file is opened; release it explicitly rather than assuming a failed play left the channel free. SFX 255 always plays the AY effects bank on any of these sub-commands, and never reserves a channel either - a reservation only ever applies to a WAV sample.

SFX n 5 stops everything sampled - whichever effect is playing on either channel - and the AY effect too, and releases both reservations. It is the "make it quiet" reset to reach for between scenes.

A cutscene does not cost you a looping bed. A video takes the sound hardware for as long as it runs, so both channels go quiet while it plays - but a loop that was ALREADY PLAYING when the clip started comes back on its own channel, with its reservation intact, as soon as the clip ends. One-shots are left stopped. There is nothing to re-trigger afterwards.

Start the bed a turn BEFORE the video, though. An effect triggered in the same turn as the video has not begun playing by the time the cutscene takes the hardware, so there is nothing there to notice and bring back: the video discards it, and the channel is silent when the clip ends. Put the SFX in an earlier entry than the video and it resumes as described.

An effect's length is no longer capped by memory - a WAV of any size plays. Files up to 24K per channel stage entirely into a fixed area kept for the purpose; once staged they replay instantly and for free, however many times you trigger them and whatever else is loaded. A larger file streams from the card as it plays instead, and the channel that played it keeps hold of it: the allocator remembers which channel last played the number, and a repeat trigger goes straight back to that channel and restarts the effect from the beginning without re-opening it or searching the card again. All a repeat costs is refilling the channel's window - a fraction of the first play's work, and no rummaging at all. Budget that refill for anything over 24K; anything under it is free to fire as often as you like.

The saving only survives while the channel is still holding the file. Play a different effect on that channel - or let the allocator steal it for one - and the next trigger of the big effect opens the card afresh, as the first play did.

A streamed (over 24K) looping effect has one audible quirk at the loop point: instead of a silent gap while the next lap catches up, the last sample briefly holds - a short click or hold rather than silence. It is easy to miss on most material, but worth an ear check on anything that leans on a clean loop.

Effects split across more than 8 pieces on the card are refused outright, whatever their size - the same ceiling video files are held to. The build stages files contiguously so this is rare in practice, but a heavily used or badly fragmented card can produce one. Defragment the card if a large effect will not play.

Bringing samples over from DOS. A DAAD Ready DOS game's SOUNDS set - at most 32000 bytes per effect, sampled 5000 to 20000 Hz - already fits every limit above, so those files drop straight in unconverted.

A restart does not stop the sound. Starting over from inside the game leaves the music and any playing sample running straight through, the same way they survive a SAVE and LOAD. RESTART, a confirmed QUIT and answering END's prompt to play again all leave the sound alone. Stop or change it yourself with SFX n 7 / SFX 0 8 and SFX n 5 if a new game should start quiet. Leaving the game for real - declining the play-again prompt, EXIT 0, a fatal error - silences everything.

A streamed effect needs real hardware to hear in full. An effect up to 24K - about one and a half seconds at the recommended rates - plays completely under CSpect, so short effects develop and test fine there. A longer effect streams from the card as it plays: under CSpect it plays only that opening ~1.5 seconds, then stops cleanly; under ZEsarUX it is inaudible entirely - nothing plays. A real Next plays a streamed effect all the way through, however long it runs.

Testing samples in an emulator. A sample playing over music drags the music's tempo down under CSpect. That is the emulator, not your game - on real hardware the tune holds its tempo while a sample plays. Judge the mix on hardware before you change anything.

BEEP plays a single tone through the AY. Write it the way the DAAD manual documents (see Getting started) - duration first, then tone - and let the compiler handle the rest.

Three rules turn a BEEP you wrote into silence, and none of them raises a compile error:

• Tones outside 48 to 238 are not tones. The compiler rewrites any BEEP with a tone below 48 or above 238 into a PAUSE of the same duration, so it becomes a silent wait rather than a note. The whole 48 to 238 range sounds, top octave included.
• Tones must be even. An odd tone is silent by design.
• A duration of 0 does nothing at all. A BEEP with duration 0 returns immediately: no tone, and no wait either. Give every tone a duration of at least 1.

Music and effects win. BEEP sounds on the third AY, the same chip the music and the sound effects use, and they have priority: a BEEP asked for while a looping song or a sound effect is playing is dropped and never sounds. The condact still blocks for its full duration, so the timing of everything around it is unchanged - you simply hear nothing. Use a sound effect, not a BEEP, for a sting over music; once a play-once tune (SFX n 6) has finished, BEEP sounds again.

Durations are scaled at compile time. Both BEEP and PAUSE durations are multiplied by this target's own note length on the way into the database, so a duration you authored is not the duration that ships. XPLAY's generated notes are scaled the same way. If you are copying timings out of an older DAAD or MALUVA guide, treat its duration tables as a starting point and check the result by ear.