1Upload the Opus audio files whose level you want to change.
2Move the volume slider: above 100% makes the file louder, below 100% makes it quieter.
3Run it; the whole file is raised or lowered by the same amount, so a large boost can make loud passages clip.
4Download the adjusted Opus file.
Adjust Opus Volume FAQ
How does Adjust Opus Volume change the level?
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Concretely, the gain is applied after decoding and the file is re-encoded, which costs one generation — so set the level you want in one pass rather than nudging it repeatedly, and use normalisation instead if what you want is a consistent perceived loudness. You move the volume slider, where 100% leaves the level unchanged, and the change is applied evenly across the whole file.
Will boosting the volume distort the audio?
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Only if it clips. Headroom is checked before the file is written, so a boost that would push peaks past full scale is flagged rather than silently squared off. If the recording is quiet because it is noisy, boosting raises the noise too.
Does the source format matter?
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It does. Opus is the best-in-class lossy codec at low bitrates and the standard for voice and real-time audio. That decides whether a gain change is an exact edit of the samples or has to go through a re-encode.
Anything specific to Opus to know?
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Yes — Opus always resamples to 48 kHz internally, so sample-rate choices you make elsewhere in the chain do not survive into it. Relevant if you plan to adjust the level more than once.
Should I use volume or normalisation?
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Use volume when you know exactly how much louder or quieter you want it. Use normalisation when you want a set of files to end up at the same perceived loudness — that is a measurement problem, not a fixed gain, and applying one when you meant the other is the usual mistake.
Can I adjust a whole batch to the same gain?
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Yes, though be careful what you are asking for: the same gain on files recorded at different levels keeps them at different levels. If you want them to match, normalise instead.
What can I upload to Adjust Opus Volume?
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MP3, AAC, M4A, OGG, Opus and WMA are the lossy codecs handled directly, and lossless sources (WAV, FLAC, AIFF) can go in the same batch. The codec is probed from the stream, so an incorrectly named file still works.
Is there a file size limit on Adjust Opus Volume?
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Yes: free accounts process audio up to 15 MB per file, which at typical bitrates is several hours of material; ffmpeg does the decoding and encoding, exactly as it would on a desktop. That is the most generous cap on the site after video, and audio work rarely runs into it.
Will Adjust Opus Volume lower the quality of my Opus audio files?
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A lossy file has already discarded detail once, and re-encoding discards more — that is generation loss and it does not undo. Wherever the job can be completed by copying the encoded stream rather than re-encoding it, that is what happens, and the audio comes back bit-identical.
Can I run Adjust Opus Volume on several Opus audio files at once?
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Yes. Upload the set and they process in parallel with the same settings, which is the practical way to handle a podcast series or an album rather than repeating the job by hand.
Do tags and cover art survive?
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Yes. ID3, Vorbis comments and MP4 metadata atoms are carried across, cover art included, so a processed file still sorts correctly in a music library. ReplayGain values are recalculated rather than copied, because a stale one is worse than none.
Does Adjust Opus Volume cost anything?
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No. Adjust Opus Volume is free without an account, and nothing is added to the audio. The upload and the result are deleted automatically about 24 hours after the job, which leaves time to download the result.
