Slowed Reverb Converter
Think of this as your audio format converter with slowed reverb built in. Upload MP3, WAV, M4A, OGG, or FLAC — export slowed reverb as MP3 or lossless WAV.
Your audio never leaves your device. All processing happens locally in your browser.
Drop your audio file here
or click to browse — MP3, WAV, M4A, OGG, FLAC up to 50MB
A slowed reverb converter is two tools in one: it transforms the mood and tempo of your audio while also giving you control over the output format. Most online audio converters do a straightforward job — MP3 to WAV, WAV to OGG — but stop there. Our converter adds the creative layer: take any supported format in, apply the slowed reverb treatment, and choose your output format based on what you need the file for.
The input side is flexible. Drag in MP3 files from your music library, WAV exports from a DAW session, M4A tracks from Apple Music (unprotected), OGG files from a game soundtrack, or FLAC rips from a CD collection. The browser's decodeAudioData handles the conversion to raw PCM automatically — you do not need to pre-convert anything. Files up to 50MB are accepted, which covers the vast majority of songs (a 5-minute WAV at 16-bit/44.1kHz is about 50MB; MP3 and other compressed formats can be much longer at the same file size).
On the output side, you have two paths. The free path gives you 128kbps MP3 with a subtle watermark — fine for casual listening, sharing with friends, or posting to social platforms that will compress your audio further anyway. The Pro path adds lossless WAV (16-bit PCM, 44.1kHz) and 320kbps MP3 without watermarks — formats suited for DJ sets, YouTube uploads, and any use case where audio fidelity matters. The WAV encoder is hand-written in about 40 lines of TypeScript (RIFF header + PCM interleave) — no external dependency, no bloat.
The conversion process itself is a single-pass offline render. While you tweak parameters in real-time using a live AudioContext, the actual export uses an OfflineAudioContext that reconstructs the same processing graph — varispeed, convolution reverb, lowpass filter, lowshelf boost — and renders the entire buffer as fast as your CPU can process it. OfflineAudioContext runs at higher priority than real-time and typically renders faster than real-time, so a 4-minute track might export in 20–30 seconds depending on your device.
For anyone used to the workflow of downloading a converter app, waiting for it to install, converting, then opening a separate editor to apply effects, a combined slowed reverb converter that does both steps in a browser tab represents a real time saving. One upload, one set of adjustments, one export — and you have your slowed reverb track in the format you need.
Frequently asked questions
- Which formats can I convert from and to?
- Input: MP3, WAV, M4A (AAC), OGG (Vorbis), and FLAC. Output: 128kbps MP3 (free), 320kbps MP3 (Pro), or lossless WAV 16-bit/44.1kHz PCM (Pro). The tool uses the browser's built-in decoder for input and our own encoders (lamejs for MP3, hand-written for WAV) for output.
- How long does conversion take?
- The offline render typically runs faster than real-time. A 4-minute track might export in 20–30 seconds on a modern laptop, or 40–60 seconds on a mid-range phone. Export time scales linearly with track length and is not affected by internet speed since all processing is local.
- Does conversion quality degrade if I convert MP3 to MP3?
- Yes — every round of lossy-to-lossy encoding adds generation loss. For the best result, start with the highest-quality source file you have (FLAC or WAV if possible). If you only have an MP3, the 128kbps export will still sound good for casual use, but avoid re-converting the exported file again.
- Why is WAV export only for Pro users?
- WAV files are uncompressed and much larger than MP3s — a 4-minute WAV is about 40MB versus 4MB for a 128kbps MP3. The Pro tier covers the higher bandwidth and storage costs associated with lossless downloads. Free users still get a perfectly usable 128kbps MP3.