Sound Design for a Cozy Idle Game
An idle game plays the same few sounds thousands of times. Notes on choosing cozy UI sounds, tuning payout pitches so they sound like a chord, muting the right things at the right time, and turning one hammer hit into a construction sound.
Sound in an idle game is different from most games. There are no explosions or dialogue. Instead, a few small sounds repeat endlessly: a coin, a purchase, a completed ride. If one of them is slightly annoying, the player hears it two thousand times in an evening and turns the sound off for good.
Finding the right sounds
The placeholder sounds were replaced with a pack of cozy UI sounds from an independent creator on itch.io, plus a few CC0 sounds from OpenGameArt. All of them are credited in the game's credits screen. The choices, in short:
- Collecting money: a soft confirmation "ding".
- Buying: first a cheerful pickup sound, then a much more discreet bubble click. You buy far more often than you collect, so the purchase sound must be the quietest.
- Hiring staff: a slightly longer chime. It is a rare, happy moment, so it can take its time.
- Opening a menu: a quiet swoosh. Closing is silent; two sounds per menu felt busy.
- Milestone, phase opened, region unlocked: short success jingles, from small to big.
- Settings switches: a tiny text blip.
Three coins that form a chord
Collecting money plays one of three variations so it does not sound mechanical. My first attempt used pitches of 0.90, 1.00 and 1.08. In isolation each was fine; one after another they sounded out of tune. The fix was to pick pitches that correspond to musical intervals, so three quick collections sound like a small chord instead of a mistake. A related surprise: the middle payout and the purchase sound were almost identical, so the purchase moved to a different sound entirely.
Knowing when to be quiet
Most of the work was not choosing sounds but deciding when not to play them:
- Automatic payouts are silent. With ten staffed businesses, the game would otherwise rattle constantly. Only coins you collect yourself make a sound.
- Special moments silence the coins. When staff is hired, a phase completes or a milestone is reached, the payout sounds pause while that sound plays.
- Menus mute the resort. While a menu is open, everything the resort does by itself is silent. Your own actions in the menu (buying, hiring) stay audible.
- Full-screen scenes mute the game. The region unlock screen used to have coins pinging in the background. Now game sounds pause while a scene is open; its music continues.
A construction sound from one hammer hit
For the construction start I found a single CC0 hammer hit. Repeated three times with slightly varied timing, it became a small "work is starting" moment. For the old reputation reset, two achievement sounds were joined into one longer fanfare.
Music
The background music, Morning at the Summit, is a generated track: calm, a little alpine, and unobtrusive enough to loop for hours. An earlier track is kept as an alternative but is not shipped. The menu swoosh was turned down twice, to about a third of its original volume, because it was louder than the music.
Regional names for the last phase
Unrelated to sound but from the same day: the fourth phase was called "Alpine resort" everywhere, including Canada and Japan. Now Canada builds a Rocky Mountain Resort and Japan a Powder Paradise. Small text changes like this are cheap and make the world feel considered.
Prices that are not round
The same evening I discovered that setting a price of €1.99 in Google Play and letting it convert to other currencies produces odd numbers everywhere. The fix became its own project the next day: a script that maintains the prices through the Play Developer API.