Mid-fight, a player at fifteen percent health crosses a heal zone. The cue fires: a shimmer near 5 kHz that decays inside 130 ms. On studio headphones it is unmistakable. Through hearing aids, for a player whose loss begins above 4 kHz, it arrives as a soft click or as nothing.
That is not an edge case. High-frequency loss is one of the most common forms, and the sparkle in many heal cues carries the whole identity. The decoration is doing the semantic work.
The fix is not more level. Move the identifying information into a band that survives, give the cue an envelope that reads at low resolution, and add a visual channel carrying the same message.
The Sparkle Sits in the First Band to Degrade
A conventional heal cue has three layers: an upward gesture, a bell or chime body, and a shimmer on top. In the mix the shimmer is often the loudest thing in the first 40 ms, because high frequencies sit forward.
That layer is the one most likely to vanish. Age-related and noise-induced loss both tend to begin at the high end, and while the slope differs per player, 4 kHz and above is a common place to see the first drop. A hearing aid can make that region audible again but not distinct, and a cue built on a 6 kHz shelf depends on the channel with the least headroom.
There is a second trap just below: 2 to 4 kHz. The ear is most sensitive there, which is why interface sounds and weapon cracks cluster in it, but many players with hearing loss have already lost resolution in the same band. A cue at 3 kHz is better than 6 kHz and still not safe.
Move the Identity Into 250–2000 Hz
The safe band is wide enough to hold a whole cue. The work is choosing where inside it the meaning goes.
Put the fundamental between 300 and 700 Hz
A triangle at 440 Hz with a second harmonic at 880 Hz gives the ear a pitch it can track without high-frequency support. The gesture can still rise: 440 to 660 Hz is a clear gain signal inside the band. In a darker palette, 330 to 495 Hz works the same way.
Build the attack in the midrange
A band-passed noise burst centred between 700 Hz and 1.5 kHz, 8 to 12 ms long, gives a defined start that survives a narrow fitting. It reads softer than a 4 kHz click, which is the right trade for a cue most players will hear.
Keep the sparkle as garnish
Air above 5 kHz can stay as garnish. Low-pass the finished cue at 4 kHz and listen once: if it is still recognisably a heal, the identity is in the right place; if it becomes a generic blip, the meaning was living in the part that disappears first. The same trade-off runs through warm versus bright EQ choices , where the bright version tests well alone and poorly through a real fitting.
The Envelope Carries More Meaning Than the Top End
Once the cue lives in the midrange, the envelope does the work that spectral detail used to do. A narrow-band sound with a flat envelope is a drone; the same sound with a clear attack, a short plateau and a shaped decay is an event. The ear reads the shape before it reads the pitch.
A workable shape: a 5 to 15 ms attack, a plateau of 80 to 140 ms near peak, then a 100 to 180 ms exponential decay, for roughly 250 to 350 ms total. The plateau matters. A cue that peaks and falls immediately is a transient, and transients are what a band-limited signal loses first.
Why the Cue Needs 250 ms, Not 90
Hearing aids do not simply amplify. Most modern fittings use wide dynamic range compression with attack times fast enough to react inside the first tens of milliseconds. A cue that is over in 90 ms can trigger gain reduction at its onset and never reach the level the player needs, so the aid ducks the thing it was meant to deliver.
A longer cue gives the compressor time to settle and hand back gain. Aim for at least 100 ms of sustained mid-band energy, which in practice means 250 ms total or more. Aided processing adds a little latency, and the reverb and noise reduction inside the aid can smear a short transient, so a defined body survives better than a single ping.
Keep the Heal Out of the Gunfire and Impact Bands
A heal that shares a band with a rifle shot loses, however well it is built. Gunfire is broadband, with crack around 1.5 to 4 kHz and body around 150 to 600 Hz; impacts sit at 60 to 200 Hz and explosions lower. A heal core at 500 Hz and a rifle body at 400 Hz fight for the same octave.
Two moves help. Pick a heal fundamental that sits in a gap in the palette, often 600 to 900 Hz in a shooter with low-tuned weapons, and keep the cue spectrally narrow, two or three partials rather than a dense stack, so it stays separable from a broadband crack.
A short duck on the music bus, 2 to 3 dB for about 200 ms, buys clarity without raising the cue; in Unity that is an AudioMixer snapshot, in Unreal a Sound Mix through a Sound Class. Do not sidechain the heal against gunfire. The heal is the rarer and more important event.
Sketch a Mid-Band Heal in the Browser
Start from a round body, keep the main pitch near 400 Hz, and shorten the tail until the cue closes inside 350 ms. Then low-pass at 4 kHz and listen again.
Open the Heal Sound Generator →Pair Every Heal With a Visual Confirmation
Audio is one channel of a message that should never depend on one channel. A heal that exists only in sound is a heal some players will miss, and the fix costs far less than a new sound.
- Health bar flash. Lift luminance and thicken the outline for 150 to 250 ms, then hold a subtle marker until the value settles.
- Particle colour and shape. Change the size or the motion as well as the colour, so it reads for players who cannot separate green from red.
- Controller pulse. A low-frequency pulse timed to the attack, 80 to 120 ms.
- Icon state change. A plus icon or a temporary ring around the health value gives the eye a record after the flash ends.
Timing matters as much as the channel. Audio and visual have to read as one event, within something like 100 ms of each other; drift further and the player starts treating them as two signals. The visual layer is also where accessibility work compounds, since what helps a hard-of-hearing player usually helps a colourblind one. Much of that is covered in designing accessible game cues .
The haptic channel deserves the same care. A pulse timed to the envelope feels like part of the sound; one fired on the event trigger feels detached by a frame or two, and players notice the gap before they can name it. The rules are in syncing haptics with sound .
Give Players Their Own Cue Volume, and Test in Mono
Put gameplay cues on their own AudioMixer group in Unity or Sound Class in Unreal, then expose a slider that affects only that group. Master volume is the wrong control, because turning it up to hear the heal also turns up the gunfire that masks it.
The slider belongs in the accessibility or audio menu, with normal focus handling, and its value should persist between sessions. About -12 to +6 dB around the mixed default covers most players, and the default needs to be findable without a mouse.
The mono check
Fold the mix to mono and listen on one earbud, then a TV speaker. In Unity, set AudioSettings.speakerMode to AudioSpeakerMode.Mono, or route the cue bus through a mono fold-down. Phase cancellation from wide stereo delays and panned layers is easy to miss on headphones and obvious in mono, and identity in the stereo field disappears with it.
Simulate the loss while you test. A low-pass at 4 kHz with a 12 dB per octave slope is a crude stand-in for the high-frequency half of a typical loss, and it shows whether the cue still says heal. When it does, the design is no longer a compromise aimed at one group of players.
The odd result is that a mid-band cue with a strong envelope often reads better for everyone. The identity sits where the ear has room, the envelope gives it priority, and the visual pairing covers the moments when audio is turned down. Players with hearing loss get a cue they can use, and everyone else gets a heal that lands faster.