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Slowed and Reverb Maker: Nightcore & 8D Audio

Free · No sign-up · Files never leave your device

Use only audio you have the right to share. The whole song is held in memory. Songs up to 30 minutes were tested in desktop Chromium.

What is a slowed and reverb edit?

A slowed and reverb edit plays a song at a lower speed and adds reverb, so it sounds deeper and as if it were played in a large room. This page makes the edit in your browser. With Keep pitch off it resamples the song, like a record turned at a lower speed, then adds a reverb built from seeded noise. Nightcore speeds the song up the same way, and 8D audio circles the sound around your head.

How it works

  1. Step 1

    Your browser reads the song

    The file is decoded by your browser's own audio engine. Nothing is uploaded.

  2. Step 2

    Pick a preset, then adjust

    Slowed + reverb, Nightcore and 8D audio set the controls for you. Change speed from 50% to 150%, keep the pitch or let it follow, and set the room size, reverb mix, bass boost and 8D circle time.

  3. Step 3

    Preview, then download

    Preview renders the first 30 seconds. Download renders the whole song in this tab and saves it as a 16-bit WAV file.

Questions

Is my song uploaded anywhere?

No. Your file is decoded, changed and saved as WAV inside this browser tab. The only thing that can load after you pick a file is the keep-pitch engine, a small piece of code that comes to your device, and only if you turn Keep pitch on.

Why does slowing a song down lower its pitch?

Playing audio slower stretches every sound wave, so it vibrates less often and sounds lower. With Keep pitch off, this page does exactly that: at 80% speed a 440 Hz tone becomes 352 Hz, and the song is 1.25 times as long. Turn Keep pitch on to change the speed alone.

What is the difference between slowed and reverb, nightcore and 8D audio?

Slowed and reverb plays the song slower, so it sounds lower, and adds a room-sized echo. Nightcore plays it faster, so it sounds higher; the Nightcore preset is 125% speed with the pitch following. 8D audio keeps the speed and makes the sound circle your head, once every 10 seconds in the preset.

Do I need headphones for 8D audio?

Yes. The circling is made with the browser's HRTF panner, which gives each ear its own version of the sound. On speakers both ears hear both channels, so the sound does not seem to move around you.

Which files work, and how long can a song be?

Any audio file your browser can play, usually MP3, WAV, M4A, FLAC and OGG. If your browser cannot read a file, the page says so; converting it to WAV or MP3 usually fixes that. The whole song is held in memory, and songs up to 30 minutes were tested in desktop Chromium. The download is always a 16-bit WAV.

Privacy: what runs where

  • Your audio is decoded, changed and turned into a WAV file in this browser tab. It is never uploaded.
  • The reverb is generated in your browser from a fixed seed, so there are no sound files to download. The keep-pitch engine (soundtouchjs) loads from 12notez.com only if you turn Keep pitch on.
  • Nothing about your file is stored on our servers.

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