Change Bit Depth

How it works

1. Choose an audio file.
2. Pick the target bit depth, and dither if you are reducing it.
3. Click Convert.
4. Download the result.

What bit depth is

Bit depth is how finely each sample’s level is stored. 16-bit gives a theoretical dynamic range of about 98 dB (CDs), 24-bit about 146 dB (recording and mastering), and 8-bit only about 50 dB, which is audibly noisy. 32-bit float stores values as numbers, with room far beyond full scale, so edited audio cannot clip inside the file.

The tool writes WAV, AIFF or FLAC. FLAC supports 16 and 24-bit; WAV and AIFF also support 8, 32-bit integer and 32-bit float. 8-bit WAV is unsigned and 8-bit AIFF is signed, as each format defines.

Reducing and dither

When the bit depth goes down, each sample is rounded to a coarser level. Rounding creates distortion that follows the music. TPDF dither adds a tiny amount of noise before rounding so the error becomes a steady, faint hiss instead. It is on by default for 8 and 16-bit when you reduce the depth and you can switch it off for a bit-exact conversion. No noise shaping is applied.

Increasing the depth, for example 16 to 24-bit, adds no detail; it only gives later edits more headroom.

Sources and limits

Compressed sources such as MP3 and AAC are decoded to full precision first, so a lower bit depth is a reduction from that. The output is always a PCM file, so it is larger than the compressed original. Sample rate and channels are not changed; use the sample rate tool for that.

Questions