---
url: 'https://adk.nht.io/api/@nhtio/adk/lib/utils/audio/functions/downmixToMono.md'
---

# Function: downmixToMono()

```ts
function downmixToMono(channels: Float32Array<ArrayBufferLike>[]): Float32Array;
```

Defined in: [src/lib/utils/audio.ts:57](https://github.com/NHTIO/ADK/blob/v1.20260713.1/src/src/lib/utils/audio.ts#L57)

Downmixes one or more PCM channels to a single mono channel by averaging samples across
channels.

## Parameters

| Parameter  | Type                                  | Description                                             |
| ---------- | ------------------------------------- | ------------------------------------------------------- |
| `channels` | `Float32Array`<`ArrayBufferLike`>\[] | The per-channel PCM sample arrays, all the same length. |

## Returns

`Float32Array`

The mono PCM samples, the same length as each input channel.

## Remarks

A single channel is returned as-is (a copy, not the original reference — callers may safely
mutate the result). Two or more channels are averaged sample-by-sample: `mono[i] = mean(channels
.map(c => c[i]))`, using each channel's own length contribution (`data[i] / channels.length`
accumulated across channels) so the result is numerically identical regardless of channel order.