Most 2D game engines don’t ship with real spatial audio. You get stereo panning, maybe some volume falloff, and that’s it. But for Phantom Frequency, I needed audio that felt physical — sounds that existed in space, moved around you, and reacted to the environment.

Here’s how I faked it.

The problem

Godot’s 2D audio gives you AudioStreamPlayer2D, which handles basic distance attenuation and left/right panning. That covers maybe 40% of what you need for a game where sound is the core mechanic.

What it doesn’t give you:

  • Vertical positioning (above/below the player)
  • Occlusion (sound behind a wall should feel muffled)
  • Early reflections (small rooms vs big halls)
  • Doppler shift for moving sources

The hack: layered processing

Instead of fighting the engine, I built a processing chain on top of it. Every audio source in the game runs through three stages:

func process_spatial(source: AudioSource, listener: Vector2):
    var dist = source.position.distance_to(listener)
    var angle = source.position.angle_to(listener)

    # Stage 1: distance + panning (engine handles this)
    # Stage 2: occlusion via raycast
    apply_occlusion(source, listener)
    # Stage 3: room reverb based on tilemap
    apply_room_verb(source)

The occlusion step is where it gets interesting…

Raycast occlusion

I cast a ray from the listener to every active sound source. If the ray hits a wall tile, I apply a low-pass filter proportional to the wall’s “thickness” (number of tiles the ray passes through).

One wall = subtle muffle. Three walls = you can barely hear it. This alone made the game feel 10x more spatial.

What I learned

The biggest takeaway: your ears are easier to fool than your eyes. A few well-placed audio cues create a stronger sense of space than any visual parallax effect. Players consistently described the game as feeling “3D” despite everything being flat sprites.

Sound is underrated in game dev. More on that in a future post.