Using ReplayGain To Balance Volume On A CD Compilation

A carefully assembled CD compilation can still sound awkward when one track is quiet, the next is aggressively loud, and an older recording suddenly jumps in level. This is common when combining vinyl transfers, cassette recordings, downloaded files and modern digital masters. ReplayGain offers a practical way to create a more consistent listening level without simply turning every file up to the same peak.

For Australian listeners making discs at home, the process suits a mixed collection built in a spare room in Melbourne, a flat in Sydney or a suburban music room in Adelaide. It also works well for playlists intended for a car stereo, a kitchen CD player or a family barbecue, provided you understand what ReplayGain changes, what it leaves untouched and how the final disc will be played.

Why Compilations Sound Uneven

Peak normalisation raises each track until its loudest sample reaches a chosen ceiling. That method prevents obvious clipping, but it does not measure perceived loudness. A heavily compressed pop recording may have a similar peak to a quiet folk recording while sounding substantially louder throughout. Older vinyl and cassette transfers can also have lower average levels because they retain more musical dynamics.

ReplayGain analyses the whole track using a psychoacoustic model designed to estimate how loud it sounds to a listener. It then stores a gain adjustment as metadata. A compatible player reads that information and reduces or increases playback level for each track. The original waveform remains unchanged, which makes the system safer than permanently applying destructive volume edits.

This distinction matters for a compilation. If a disc contains a 1970s Australian rock track, a softly recorded spoken excerpt and a modern dance master, matching their peak levels will rarely produce a comfortable sequence. Perceived loudness matching creates a better starting point, although artistic choices still matter. A deliberately quiet opening may need to stay quiet rather than being forced into mathematical uniformity.

What ReplayGain Measures

ReplayGain commonly provides two related values: track gain and album gain. Track gain treats every song independently, making it useful when a compilation is played in shuffle mode. Album gain analyses the collection as a connected programme, preserving level differences between tracks that belong together. For a mixed CD, track gain is generally the more useful choice because the songs came from separate albums and mastering sessions.

The analysis also records a peak value. Gain correction can expose clipping if a track contains samples close to digital full scale. Some players apply a safety adjustment based on the peak information, while others offer a preamp setting or clipping prevention option. ReplayGain is therefore not a promise that every file can be boosted freely; a quiet track may have a high true peak that limits how much level can be added.

Different software uses ReplayGain 1.0 tags, newer loudness standards such as R128, or its own normalisation system. The labels may look similar while the calculations and tag names differ. Before starting, check that the program used for analysis and the player or burning workflow interpret the same metadata. A desktop media player may support ReplayGain during playback, while a basic CD player will ignore it completely.

Prepare Vinyl And Cassette Sources

Begin with the cleanest transfer you can make. Set the turntable, cartridge, phono stage and recording interface correctly, and leave sensible headroom rather than recording right against 0 dBFS. For cassettes, clean the tape path, use the correct Dolby setting where appropriate and capture both sides in one uninterrupted session when possible. These steps reduce clicks, hum and dropouts that volume processing cannot repair.

Good tape handling is especially valuable for older cassettes that have spent years in hot Australian cupboards or garages. The practical advice in these cassette care tips can help protect the source before you digitise it. A cleaner transfer gives the loudness analyser a more reliable signal and avoids mistaking noise or a sharp click for meaningful musical information.

Edit the captured material before measuring it. Remove long leader sections, accidental silence and obvious handling noise, but avoid cutting natural fades or room ambience. Save a lossless master, preferably WAV or FLAC, and keep an untouched copy separate from the files used for compilation. For Australian collectors converting LPs bought from local record shops or tapes found at markets, this archive becomes valuable if you later want a different running order or a higher-resolution transfer.

Apply Gain Before Burning

Use a ReplayGain-capable tagger or audio editor to analyse the finished track files. Foobar2000, Mp3tag with suitable tools, and several open-source audio applications can calculate track gain and write the relevant tags. Some free recording programs can also prepare and export the source files; this overview of free recording software is useful when assembling a transfer workflow.

There are two ways to proceed. The first is metadata-only normalisation: tag the files, play them through compatible software, and leave the audio samples unchanged. The second is rendered normalisation: use the calculated gain to create new audio files with the adjustment permanently applied, then burn those files as an ordinary audio CD. The second method is necessary for most standalone CD players because Red Book audio CDs do not generally carry ReplayGain tags that a player can interpret.

When rendering, set a conservative peak ceiling and inspect the software’s clipping warning. Do not assume that increasing a quiet track by 8 dB is harmless. If it clips, reduce the amount of gain, use a limiter sparingly or accept a lower level for that track. A limiter can prevent digital overs, but heavy limiting defeats the purpose of preserving the character of a vinyl or cassette transfer.

Check The Disc And Listening Order

After rendering, listen to the complete sequence rather than checking only isolated songs. Loudness matching can reveal problems that were hidden when the tracks were auditioned separately: a hissy cassette may become distracting, a clipped transfer may sound brittle, and a quiet acoustic performance may need a small artistic lift. Use both headphones and ordinary speakers, since the final disc may be played in a lounge, vehicle or portable stereo.

Leave short gaps where the source material calls for them, and consider whether the compilation should use track gain rather than album gain. A live set, soundtrack or continuous DJ-style programme may benefit from album-style treatment, while a “best of” collection usually needs independent track matching. Crossfades and silence can be added after the level decisions, because editing them earlier can alter the analysis.

Burn a test disc at a moderate speed using reliable media, then verify it in the equipment that will actually be used. Some older players dislike certain recordable CD brands or fail to read discs burned with unusual settings. Keep the original files and the rendered pre-burn files clearly named. If a track needs replacing, you can rebuild the compilation without repeating the vinyl or cassette transfer.

Practical Settings For A Reliable Result

ReplayGain is a starting point, not a substitute for judgement. The best compilation may contain modest level differences because contrast gives the programme shape. A sequence that is technically identical in loudness can feel flat, especially when quiet music is followed by a recording intended to make a dramatic entrance.

Use these recommendations when preparing the files and final disc:

• Analyse finished, edited tracks rather than raw captures with long silences.
• Prefer track gain for a mixed compilation and album gain for a coherent original album or live programme.
• Keep lossless masters before applying any permanent gain or limiting.
• Check peak warnings and leave headroom instead of forcing every track towards digital full scale.
• Test the rendered files on headphones, speakers and the intended CD player.
• Retain ReplayGain tags even after rendering, but document the gain that was applied to avoid double adjustment.

Australian users should also keep the legal side straightforward. Format shifting music that you legitimately own may be covered by specific provisions of the Copyright Act 1968, but conditions apply and laws can change. A compilation made for personal listening is different from uploading the files, giving copies to customers at a market stall or distributing them through a social media group. Check the current Australian Copyright Act and licensing guidance before sharing beyond your household.

Create the compilation in your audio editor, analyse the final track set, render only when the destination player requires it, and burn a test copy. ReplayGain can turn a collection assembled from LPs, cassettes and digital sources into a much more comfortable listening experience while preserving the original masters for future projects. Use the finished disc regularly, note any tracks that still feel out of place, and refine the sequence with your ears as the final judge.