What Is the Difference Between Lossless and Lossy Audio and Does It Actually Sound Better

[RoughDaemon]

I don't quite understand the difference between lossless and lossy. What Is the Difference Between Lossless and Lossy Audio and Does It Actually Sound Better?

[LuckySentinel]

The distinction between lossless and lossy audio formats is one of the most debated topics in audio enthusiast communities and one of the areas where genuine technical differences intersect with genuine human perceptual limits and genuine audiophile mythology in ways that are hard to separate.

Lossy compression formats like MP3 and AAC work by analysing audio and removing information that psychoacoustic models predict the human ear will not notice. A quiet sound immediately after a loud one may be inaudible due to auditory masking, for example, so lossy codecs can discard it. A 320kbps MP3 uses significantly less storage than a lossless file while retaining most of the perceptually significant audio information. The quality of lossy compression has improved dramatically and modern AAC at 256kbps, which is what Apple Music and Spotify stream at for high-quality settings, is indistinguishable from lossless to most listeners in most circumstances on most playback equipment.

Lossless formats like FLAC, Apple Lossless ALAC, and WAV contain all the original audio data with no information removed. They are larger files but perfectly reproduce whatever was recorded or mastered. Hi-res lossless extends this to sample rates and bit depths above the CD standard of 44.1kHz and 16-bit.

The honest answer about whether it sounds better is nuanced. Blind listening tests consistently show that most people cannot reliably distinguish between high-bitrate lossy and lossless audio under controlled conditions on quality playback equipment. This does not mean the difference does not exist technically, it does. It means the difference is often below the threshold of human perception, particularly when streaming over the internet introduces other variables, and particularly on average playback equipment. The difference is most likely to be audible on high-end headphones or speakers in a quiet environment with well-mastered recordings.

[SortedMate]

Blind ABX testing is the gold standard for answering this question honestly and the results consistently show that trained listeners struggle to reliably identify lossless over high-bitrate AAC. The subjective sense of difference is real but it does not survive blinding in most cases