Lossless, bitrate and the equalizer: what changes the sound and what does not
Audio attracts more confident nonsense than any other part of media. Some of it is real and measurable, some is real but inaudible through the headphones you actually own, and some is marketing. It is worth separating the three before spending storage or money on any of them.
- Lossless
- FLAC, ALAC, WAV — bit-for-bit identical to the source. Roughly 5× the size of a good lossy file.
- Lossy done well
- AAC at 256 kbps or Opus at 128 is transparent to most listeners on most equipment.
- The real variable
- Your headphones and the room, by a margin so large the file format is a rounding error.
What lossless means, precisely
A lossless file reconstructs the original recording exactly — every sample, bit for bit. FLAC, ALAC, WAV and AIFF all do this; FLAC and ALAC compress it to around half the size of raw audio, WAV and AIFF do not compress at all. Decode a FLAC and a WAV of the same master and the output is identical, so the choice between them is purely about file size and which devices read them.
A lossy file throws away information that the encoder’s model of human hearing says you will not notice, and cannot get it back. That sounds worse than it is: a modern encoder at a sensible bitrate is genuinely transparent to most people on most equipment. MP3 at 320 kbps, AAC at 256, Opus at 128 — the differences in a proper blind comparison are small enough that most listeners score at chance.
The honest summary is that lossless is worth it for archiving, for anything you might re-encode later, and for the peace of mind of knowing nothing was discarded. Whether you can *hear* it depends far more on your headphones, the room and the recording than on the format. Both statements are true at once, and the argument usually happens because people are defending different ones.
Audio formats worth knowing
| Format | Type | Typical use | Notes |
|---|---|---|---|
| FLAC | Lossless | Archiving, downloads from stores like Bandcamp | Open, universal outside Apple’s own apps |
| ALAC | Lossless | Apple libraries | Technically equivalent to FLAC, better native support on Apple devices |
| WAV / AIFF | Uncompressed | Production, masters | Huge, and carries almost no tags |
| AAC | Lossy | Everything Apple, most streaming | The best-supported lossy codec; transparent at 256 kbps |
| MP3 | Lossy | The universal fallback | Ancient, less efficient, still plays on literally everything |
| Opus | Lossy | Podcasts, voice, WebM audio | The most efficient of the lot at low bitrates |
| AC-3 / DTS | Lossy, multichannel | Film soundtracks | Common inside video files, not decoded by Apple’s built-in player |
The numbers, and which ones matter
- Bitrate
- Bits per second. The dominant quality variable in lossy audio, and meaningless for lossless — a FLAC’s bitrate just describes how compressible that particular music was.
- Sample rate
- 44.1 or 48 kHz covers the entire range of human hearing, with headroom. 96 and 192 kHz files exist and are useful in production; for listening, the audible benefit is somewhere between negligible and imaginary.
- Bit depth
- 16-bit gives about 96 dB of dynamic range, more than any listening environment that is not a treated studio. 24-bit matters while recording and mixing, where headroom is being spent.
- Gapless
- Whether track two starts the instant track one ends. Live albums, DJ mixes and most classical music are ruined by a quarter-second of silence between tracks, and this is far more audible than any of the numbers above.
- Loudness normalisation
- Levelling playback so a quiet album and a loud one need the same volume setting. It changes nothing about the file — it adjusts playback gain.
What an equalizer actually does
An equalizer boosts or cuts specific frequency ranges. A 10-band EQ splits the audible spectrum into ten and gives you a slider for each — roughly 32 Hz at the bottom, where you feel more than hear, up to 16 kHz at the top, where cymbals and sibilance live. It is not adding anything that was not recorded; it is changing the balance of what is there.
Where it earns its place is compensating for hardware and environment. Cheap earbuds with no bass extension, a car where road noise swallows everything below 100 Hz, a podcast recorded too quietly, headphones with a harsh peak around 6 kHz that becomes fatiguing after an hour — all of these are corrections an EQ makes properly.
Two rules make an EQ useful rather than destructive. Cut before you boost: reducing the frequencies you do not want leaves more headroom than raising the ones you do, and avoids clipping. And move in small amounts: ±3 dB is a real, audible change, while ±12 dB is a distortion pedal. Most factory presets named after genres are boosting far too aggressively, which is why they sound impressive for thirty seconds and tiring after five minutes.
What actually improves listening, in order of effect
If the goal is better sound rather than better numbers, the order looks like this.
- Headphones or speakers that suit you
The largest variable by an enormous margin, and the only one you will hear immediately.
- A decent fit or seal
On in-ear headphones, the wrong tip size loses more bass than any format choice could restore.
- The recording and the master
A well-mastered 256 kbps AAC beats a loudness-war lossless remaster every time.
- Gapless playback and correct resume
Whether an album flows as intended, and whether a two-hour recording remembers where you were.
- A gentle EQ correction
Small cuts to fix a specific problem you can name.
- Lossless files
Real, worth having for archiving, and last on the list of things you will notice.
Listening on each device
Where playback control matters most: background listening, the Lock Screen, a sleep timer, a watch on your wrist and a widget on the Home Screen.
The device people actually leave playing in a kitchen or a workshop. Background audio and a well-behaved Lock Screen matter here for the same reason.
No battery constraint, so software decoding of anything exotic is free, and the player can live in its own window while you work.
Questions people ask
Can I hear the difference between FLAC and 256 kbps AAC?
On typical headphones, in a normal room, with normal music — most people cannot, and blind tests have shown this repeatedly. On good gear, in a quiet room, on sparse acoustic material, some people can some of the time. Both of those are true, and neither makes the other wrong.
Does an equalizer reduce quality?
It changes the balance, which is the point. It can cause clipping if you boost hard enough to push the signal past full scale — the reason to cut rather than boost. Used gently, it is the single most effective correction available for imperfect headphones.
Why does my album have a gap between tracks?
Either the files were encoded without gapless information, or the player is not honouring it. Lossless formats carry it reliably; MP3 depends on tags that many encoders never wrote. On a live album it is the most annoying flaw in playback and has nothing to do with audio quality.
Is 24-bit/192 kHz audio better?
For production, yes — headroom while editing is real. For listening, the extra range is above human hearing and below the noise floor of any room you will sit in. The files are three times the size and the audible benefit is not there. A well-made 16-bit/44.1 kHz master is not the limiting factor in anything you own.
How FoxDL plays music and audio
FoxDL is a music player as much as a video player, and both run on the same engine — so a FLAC album and the DTS track inside a film take the same path, in the same library.
- FLAC, ALAC, WAV, AAC, MP3, Opus, Vorbis, AC-3, E-AC-3 and DTS all play directly.
- A 10-band equalizer with presets, including corrections aimed at a car and at spoken-word listening.
- Playback speed, a sleep timer and gapless resume shared across music, podcasts and video.
- Background listening with proper Lock Screen controls and the right artwork, plus AirPlay to a receiver.
- An Apple Watch companion and Home Screen widgets on iPhone and iPad, and Siri shortcuts for what you repeat.
- Car Mode on iPhone — oversized controls for a dashboard mount. It is not CarPlay.
The equalizer is a Pro feature; format support, speed, sleep timer and background listening are free on every device.
Questions people ask about this
- Does FoxDL have an equalizer?
- Which video and audio formats does FoxDL play?
- Can I switch the audio track on a dual-audio file?
- Is there an Apple Watch app, widgets and Siri support?
Keep reading
Nobody owns podcasting, and that explains almost everything about it
Podcasting is RSS with no owner. That explains the offline, the delays and the dead stations.
Why your iPhone opens one video file and refuses the next
Containers, codecs, and the three ways to watch a file iOS refuses to open.
Subtitles, audio tracks, and the three ways they go wrong
Embedded versus separate files, the encoding that mangles accented letters, and how to fix drift.
Your library, finally in one place.
Free to download. No account, no sign-up, and the whole feature set is in the free version.