There is not a single audio file behind the music in Powderline. Press L and the radio starts composing: a key, a tempo, a chord progression, a groove and a little melody, rolled from a seed the moment a track begins, then played on instruments built out of oscillators and filters in your browser. That has always been true of POWDERLINE FM, the lofi station. What changed this week is what happens between tracks — there is no longer any silence there — and that a second station, APRÈS FM, now plays deep house the same way.
Music written as it plays
A POWDERLINE FM track is about two minutes long and has the shape of a real lofi tune: an intro, a groove, a section where the melody comes in, a break, the groove again and an outro. The chords come from the turnarounds lofi lives on — ii–V–I, I–vi–ii–V and their cousins, voiced as ninths and elevenths — and each chord is voiced close to the one before it, so the harmony moves the way a pianist's hands would rather than jumping around the keyboard.
The instruments are small on purpose. The electric piano is two sine waves, one modulating the other, with the modulation falling away after each strike: the bark of the tine, then the warm body. The bass is a rounded triangle wave, the drums are a pitched sine and filtered bursts of noise, and the lead sits somewhere between a flute and a muted vibraphone. Everything runs through a shared tape stage: a little wow and flutter that bends the pitch by a few cents, gentle saturation and a closed top end. A note is two or three audio nodes, so the music keeps time even when the game is busy.
It once played over vinyl crackle. The random pops sounded exactly like audio breaking up, so players reasonably assumed something was wrong. The crackle went.
The gap between tracks
Until this week, every track ended the same way: the outro faded the station out, there were 2.2 seconds of silence, and the next intro faded back in. Skipping with N did the same in a hurry. On a radio meant to sit under a run, that silence was the loudest thing about it.
The fix is the one a DJ uses: two decks. Each deck has its own set of instruments, its own tone filter — the lowpass that opens and closes with the shape of a track — and its own fader, and both feed the same tape stage. Two bars before a track ends, the next one starts on the other deck, under the outro, and the two faders cross over those two bars.
Equal power, not equal steps
A plain linear crossfade leaves a dip in the middle, where both tracks are at half volume and the music seems to back away. The faders follow an equal-power curve instead, a quarter of a sine wave each way, so the combined loudness holds steady from the first bar of the blend to the last.
The harmony helps too. About three times in four, the next track picks a key that sits well with the last one — the same key, or a fourth or a fifth away — so the overlap sounds like a key change rather than two songs arguing. Skips blend in the same way, over 1.6 seconds, and they work even when you skip in the middle of a blend: the station simply takes a third deck for the new track.
Checking it without listening
Music is easy to fool yourself about, so the blend was measured rather than judged by ear. The radio can be rendered offline, faster than real time, into a sound file, exactly as it would play in the game. Four minutes and twenty seconds of it, covering two track changes, were cut into quarter-second slices and the loudness of each one measured. Not one slice dropped below −60 dB, which is as close to silence as a recording gets; the quietest moment sat about 8 dB under the median, which is just music breathing. The old version had at least 2.2 seconds of dead silence at every change.
APRÈS FM
Après-ski is what happens after the lifts close, and APRÈS FM is its soundtrack: deep house for after the last chair. It runs on the same engine as POWDERLINE FM — the decks, the tape stage, the scheduler and the crossfades — but composes its own music.
Each track is built the way a house record is built for a DJ to mix. It opens with eight bars of kick and hats with the filter shut, then the bass and the chords come in. The groove has off-beat electric-piano stabs that duck under every kick and swell back between them — the pumping sidechain sound the genre is known for. A breakdown drops the kick for a slowly swelling pad and a plucked lead, a clap roll leads into the drop, and the record ends on eight bars of kick and hats again. The chords are minor ninths and elevenths over the progressions deep house leans on, the bass is a sub sine under a sawtooth that growls through a closing filter, and the clap is three quick bursts of noise, flammed like a real one.
Beatmatched, like a DJ
Crossfading two lofi tracks at different tempos is fine; crossfading two house records at different tempos is a trainwreck, because the kicks drift apart and gallop. So APRÈS FM picks one tempo, somewhere between 120 and 124 beats per minute, and keeps it for the whole session. Every track starts exactly on the bar of the one it mixes into, and the blend runs over eight bars instead of two. The new record's kick-and-hats intro plays under the old one's kick-and-hats outro with the two kicks landing together, which is what a beatmatched mix sounds like.
Level with its neighbour
A four-to-the-floor kick carries far more energy than a lofi groove, and the first version of APRÈS FM was about 4 dB louder than POWDERLINE FM. Switching stations would have jumped in volume, so the station was trimmed until both measure the same, around −23 dBFS on average. The first breakdowns also fell into a hole, nearly 20 dB under the groove, which on a laptop speaker sounds like the music has stopped. The pad and the lead were lifted until a breakdown sits a few decibels under the groove: a breath, not a gap.
Why not just stream a mix?
The easy way to put deep house in a game would be to play someone else's mix, streamed from a video site. Streaming someone else's recording inside a game is not open to a small project: the music belongs to its artists and is not licensed for that use, and the rules for embedding a video player do not allow hiding it to play audio only. Generated music sidesteps all of that. It belongs to the game, never repeats, costs nothing to download and works offline and on game portals.
Switching stations
Press K to switch between POWDERLINE FM and APRÈS FM, or use the station button next to the radio switch in SETTINGS. L still turns the radio on and off and N skips a track — which now blends instead of cutting out. If you are signed in, the station you pick follows your account to your other devices. The key map is on the controls page; the changes are in the changelog as POWDERLINE FM never goes quiet and APRÈS FM, a deep house station. The rest of the week's work is in A week on the mountain.
