Gunnar Van Vliet, self-described Mac user and music lover, wanted to know how good AAC was in comparison to MP3, and finally to see if it could come close to standard CD. So, Van Vliet encoded the same track in iTunes using 96, 128, 160 and 192 kbps AAC and MP3, and one AIFF for reference. The track is from the Kansas City Soundtrack – “I Surrender Dear.” It’s a very well recorded live in the studio jazz piece and it’s a track that Van Vliet says he knows very well. It features a solo saxophone and trumpet which are clearly localized in the mix and very closely resemble the real instruments.
The usual caveats of testing apply. This is an unscientific test and it’s not double blind, but Van Vliet thinks that this test can be of use if you’re trying to compare something to a known reference. Van Vliet’s system consists of Yamaha RX-595 receiver, CDX-490 cd player, and Energy Veritas 2.1 speakers. He describes the system as “well balanced and revealing.” Van Vliet told RecordStoreReview.com, “I’ve compared it to many other systems over the years and it never disappoints.”
Van Vliet’s test results:
128 kbps MP3 – Flat, compressed sound/dynamics. Rolled treble (quite bad). One dimensional, plodding bass.
– Tonal Accuracy – 5/10
– Imaging/Soundstage – 5/10
– Naturality – 4/10
– Musicality – 4/10
– Total – 18/40
128 kbps AAC – Rolled treble, but not too bad. Light bass especially in transients/impact. Compressed dynamics. Surprisingly musical.
– Tonal Accuracy – 7/10
– Imaging/Soundstage – 6/10
– Naturality – 6/10
– Musicality – 8/10
– Total – 27/40
AIFF: Beautiful sparkle to piano keys. Generally filled with much more life and atmosphere on a tactile level. Far more musically involving. This is the reference piece, so it naturally gets a perfect 40/40 score.
On the whole, there weren’t any surprises. Van Vliet’s observations echo what most people have said about AAC vs. MP3. AAC is higher quality at the same bit rate, so you can use a smaller file to achieve the same quality as MP3 which is a good thing for portable and computer users. Ultimately, both formats still sound pretty bad in their practical ranges compared to CD.
Also, Van Vliet didn’t test 256 or 320 kbps because it’s impractical for most users to use these encodings. The Apple Music Store uses 128 kbps, and Van Vliet suggests that if you have room for 320 kbps and you care about sound that much you’ll probably use AIFF or just play the CDs themselves.
Full article and results using 96, 128, 160 and 192 kbps AAC and MP3 here.