About Apple Digital Master Premium Music

Apple opened the Apple Digital Master service on iTunes, introduced to bring premium studio-like sound quality to everyone. So I want to write an objective article to share with everyone about this new high-quality Apple audio standard.

First, the quality of Apple Digital Master can be understood as the rebranding of the “Mastered for iTunes” standard that has been introduced on iTunes since 2012. This new step by Apple is partly aimed at refreshing its image and reaffirming its position and perspective in music streaming.

1/ What is Apple Digital Master?

To understand the root of the problem, you need to know the AAC (Advanced Audio Coding) codec standard used by Apple. That is a lossy codec developed by Apple to compress and encode audio signals without losing too much information compared to the original audio file.

In 2003 when iTunes was released, Apple used the 128kbps AAC standard compressed from the original CD file and received a lot of success when selling more than 100 million songs in the first year. The sound quality of the 128kbps AAC stood out much more than the popular MP3 standard at the time.

Since 2007, iTunes decided to upgrade the quality of music files to AAC 256kbps format, which can store more audio information with faster bandwidth and decoding speed. Over the years, Apple’s SRC resample technologies have also become much more advanced. Since 2012 have made it possible to resample original music files in Hi-Res quality up to 24-bit better than 16-bit CD quality.

Apple’s resample SRC (Sample Rate Conversion) technology uses a 32-bit floating-point conversion algorithm when converting 24-bit music files to keep the value points out of the allowed range. That helps the AAC file retain almost the entire dynamic range of the original file and does not need to use dither noise buffering to reduce distortion, resulting in much lower background noise than other resampling methods.

Even Apple confidently asserts that the AAC 256kbps Apple Digital Masters file has better sound than standard CD quality.

256kbps AAC files, in addition to being sold on iTunes, are also used by Apple on the Apple Music music streaming service.

The Apple Digital Master standard is granted to AAC 256kbps music files compressed from the original studio files (master) of 24 bits or more quality and verified by Apple Music.

In short: Apple will still use the 256 kbps AAC codec for streaming on iTunes and Apple Music, not releasing the high-quality Lossless standard as rumored.

2/ How will Apple Digital Master files be different from previous files on iTunes?

To qualify for Apple Digital Master, manufacturers must provide 24-bit high-quality original recordings to Apple. The input quality of the original recording is more rigorously controlled than before:

The original recording file’s quality must be 24-bit standard music with an optimal sampling frequency of 96kHz (Apple still accepts 48kHz and 88.2kHz sampling frequencies). At this point, many of you will realize that this is the standard of File Hi-Res Audio.

– Apple will not accept the case of recording music in 16-bit then using accompaniment and upsample to 24-bit.

– Old CDs or vinyl albums must be ‘remastered’ to achieve 24-bit quality. The remastering process must be similar to that of a new album, and there must be a noticeable improvement over the previous recording.

– The producer must ensure the quality of the recording with the dynamic range of the recording is well represented, without the volume threshold being too loud and no signal clipping. These are the things that many audiophiles are interested in, especially after the “loudness war” battle to regain good recording quality on expensive sound systems.

– Manufacturers must pay attention to the AAC end format, considering all the advantages and disadvantages of the format. Apple will provide tools and software for manufacturers to check the quality of the AAC file, listen to the AAC file and compare it with the original recording. Adjust to optimize the original file’s sound quality to guarantee the AAC file’s quality, similar to the original recording.

That is very important because only if the input quality of the original recording improves, the quality of the output file will improve. That is even more important than the transmission format because a well-recorded, accurate song, even downsampled to a lossy format, will still be better than a poorly recorded song that sounds lossless.

And now, if you pay attention, 90% of classical songs have met Apple Digital Masters standards because, for classical music, poor sound quality is easy to detect.

3/ Will Apple introduce Hi-Res music streaming packages like Tidal and Qobuz?

The possibility of Apple introducing a lossless music stream package or Hi-Res Audio similar to Qobuz, Tidal is very, very low at the moment. However, Apple is completely capable of doing it.

The software and hardware on the iPod Touch / iPhone / iPad can fully decode 24-bit Hi-Res music. Still, according to Apple, the quality of its special 256kbps AAC file is not much worse than the recording 24 bit original. In addition, Apple’s marketing also focuses on convenience, compatibility with many devices, reaching many customers (even the slogan says ‘for everyone) instead of focusing on a small segment called audiophiles.

If we do a simple comparison between the number of users using the most famous music streaming services with lossy quality, Spotify (108 million paying subscribers, 220 million total users) and Apple Music (60 million users). Compared to the high-quality lossless music streaming services for audiophiles, Tidal (more than 3 million people) and Qobuz (250,000 people), this is too small a number for Apple to care about.

The bandwidth of AAC files is much more economical than 24-bit WAV files, reducing storage space on the server. That is convenient for both Apple and users and can be used anywhere with faster transfer speeds, and is much lighter than standard Hi-Res files.

Currently, on Apple Music, there are many songs from the same source with high-quality Apple Digital Music recordings on iTunes, so users can also experience high-quality music online.

Apple’s Ecosystem system is built on AAC codecs from Apple Music, iTunes to Bluetooth codecs for wireless transmission, audio codecs in video standards. So changing to lossless quality cannot happen in a short time but requires a lot of time to build.

One caveat, however, is that when producers send 24-bit original recordings to Apple, Apple Music also owns full ownership of the 24-bit original recordings and AAC versions that are released. So if one fine day Apple introduced to sell 24-bit music, it wouldn’t be strange.