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Audio

OMG, Apple Music is Good! But not Perfect

Apple makes lossless transfer its fixed network delivery standard. On playback, the original Red Book master results. And it is quite good.

For a million years I’ve been scowling at Apple Music and the iTunes Store as Apple sold lossy-compression renderings of all of the music offered. All of the gripes to Apple Feedback finally payed off somewhat with the initiation of Apple Music Lossless. An earlier article explained the switchology of setting up Lossless streaming and downloads. This article talks about the results. It’s simple, Apple Lossless delivers the Red Book original. Spatial and Dolby Atmos are another thing. It’s all about the mastering, who did it and their goals for the mix.

Revisions

  1. 2021-06-25 Original

References

  1. https://retired-moocher-dave.org/2021/06/11/apple-music-lossless/ Announcement and preference settings
  2. https://youtu.be/xE_BnfVMFi0 Audio Fixation on Lossless Audio
  3. https://www.gearpatrol.com/tech/audio/a36585957/lossless-audio-explained/ Gear Patrol surveys the broader streaming music market

Lossless Streaming Changes the Music Business

Until recently, I played only music recorded on purchased media, usually CD and recently, served by my Roon Core. Then I subscribed to Tidal and Qobuz. Now, the majority of my music comes from these sources. But, I still buy music.

When do I stream a title?

Roon does a wonderful job of music discovery, especially in Jazz. Roon Radio finds tracks like those I played to start a listening session. When I hear something I like, I add it to my library. If I really like it, I give it a wishlist tag for eventual purchase.

Criteria to purchase a title?

When do I purchase a title? I like the music. It’s my taste and well recorded. But there is more.

  1. The artist is living. Prince, Jimi Hendrix, and Bach no longer need to receive royalties.
  2. The artist likely had a raw deal from his label in the early years and is in need of retirement income. Many classic blues, R&B, and other artists are in this fix. Somehow their platinum titles lost money so they received no income. Labels were notorious for keeping artists in debt bondage.
  3. The artist is a young artist. The kids need shoes. Their work is good but not mainstream.
  4. Streaming royalties cover the Starbucks bill.

How Streaming Services pay artists

There are two models in use currently, proportional pay over the community and proportional subscriber by subscriber. It’s a simple matter of programming.

Each service divides its subscription money into three pots, profit, operating expenses, and royalties. The royalty fraction is divided among the artists. The deal with the label to license a catalog is an operating expense.

The service tracks the play counts of each title so it knows what its listeners are listening to. This data is used to tune up next recommendations, artists recommendations, album recommendations, and title recommendations. The service tracks how these are changing over time and monthly adjusts what it is pitching to you.

What most services do

The service also totals up the minutes played globally. It does this to purchase content distribution service and to check the bill. It also does this to calculate royalties. It keeps a sum by artist. Each artists receives the fraction of total minutes he was played times whatever the monthly royalty total is.

What specialty services do

Specialty services are using a different algorithm that reflects how each subscriber is apportioning his listening minutes. It divides the subscriber fee into profit, operations, and royalties monies. It divides the royalty money between artists proportional to the subscriber’s listening minutes to each artist. This requires some change to the data model, some change to the royalty calculation, and a detailed accounting going to each royalty management service (ASCAP, BMI, etc). But it is doable and at least one service is doing so and more may follow. This is a good thing to pitch Uncle Tim.

Apple Music standard quality is “Lossless”

Apple Music’s standard quality is “Lossless”. That appears to mean that Apple has encoded the original Red Book CD master using ALAC, Apple Lossless Audio Codec.

Streaming via a home or work network delivers the lossless version. Streaming over a cellular connection currently delivers an Advanced Audio Codec compressed version at 256 kBPS. This level of compression looses some of the transient leading edge and some of the small detail like the shimmer of properly tracked cymbals but tonal color and balance are preserved.

What is Lossless?

When music enthusiasts speak of “lossless” encoding, they mean that encoding followed by decoding returns the original sample stream. Bit for bit, or “bit perfect” in audiophile argot. Its that simple. The garbage out is exactly the original garbage in.

Under the Covers

Both Apple Lossless (ALAC) and Free Lossless Audio Codec (FLAC) operate similarly. Both take advantage of the commonality between the left and right channels.

In audio, stereo FM and stereo LP mastering have taken advantage of this commonality by combining the stereo channel pair to sum (or mono, L+R) and the difference (L-R). This allowed the new media to be compatible with legacy consumer players.

In an LP, the mono signal was cut vertically in the groove and the difference was cut laterally (parallel to the record’s radius) in the groove. Because the two cutting directions were orthogonal, the two signals could be recovered by two pole pairs in the phono cartridge. By correctly pairing the two signals, adding gives 2L while subtracting gives 2R. This happens passively inside the cartridge body.

Stereo FM did much the same thing. As do ALAC and FLAC. Conceptually, the channel sum and difference are encoded using a linear predictive encoder, decoded, and the error determined. The error is known as the “residual”. Since computers like complex math, this matrixing may happen in the complex plane.

The predictive encoding plus the residual become the ALAC or FLAC result. The two algorithms differ in the details of the linear predictive encoders used. They may also differ in the initial matrix transformation used. The Duck is not finding the math so you’re safe for now.

For playback, the linear predictive encoding is expanded (decoded) and combined with the residual, to create the original samples. This is what makes it lossless. The reconstructed playback stream is exactly equal to the original master before encoding.

Which is Better, ALAC or FLAC?

Neither! Well, ALAC output equals the Red Book master. FLAC output equals the Red Book master. The compressed stream has very similar length. So ALAC and FLAC are functionally equivalent and indistinguishable to the listener.

And Apple Music’s Sound?

Preparation for streaming is yet another opportunity to do mastering. The choice and quality of the “studio master” and the mastering engineer’s choices largely determine the sound.

  • Do I provide a faithful copy of the Red Book?
  • Do I equalize it for young people and ear buds?
  • Do I equalize it to be heard in a. noisy auto?
  • Do I punch it up for boomer faded hearing? You get the picture.

What choice has Apple asked of each artist’s label and Apple’s mastering engineers.

To my ears, Apple Music and Qobuz playback of a record I have in Red Book are indistinguishable. I’ve played a number of records I’ve heard for 50+ years and both are spot on with the original LPs which are in a box somewhere in the manor. This is the choice I prefer as a recorded music fan. I’m perfectly capable of honking up the playback to my taste, thank you. How that needs to happen depends on the listening environment and rig. So thank you for leaving the equalization choices to me.

High Definition Hype

A number of labels are trying to squeeze the boomers for a few more pennies by reissuing records and out takes of semi-retired artists like Bob Dylan, Neil Young, etc who have licensed their back catalogs to ensure a retirement income stream.

In general, these reissues are thrown together hurriedly without even regard to matching up track levels. Stay away from the flock of reissues now coming out. With modern streaming you can hear the thoughtfully produced artist-approved originals.

The second thing I’m hearing is that the reissue producer is tampering with the original master to make a “high definition” copy at 96 kHz or 192 kHz. Juice up the level, the low end, and the top end and hard of hearing boomers will throw money at you. Or not.

A digital Red Book master is upsampled, tossed into a container and put out. These usually have a very harsh sound, especially if they have been MQA encoded too. Ultrasonic artifacts of the sloppy remastering are aliasing into the base band in a very painfully evident way. One offender, Cat Steven’s reissue label, has released HD reissues of Tea for the Tillerman, Teaser and The Firecat, etc from his early records. These HD reissues are evil. The original Red Books are glorious as were the LPs back in the day.

The music is perfect, the architecture is not

Apple Music playback currently ties up an iPhone, iPad, or Mac process to pull music from Apple Music and hand it off sample by sample to the local playback device. When playing to an AirPlay endpoint for delivery to the big rig, a similar pacing is used. Using the phone for a call or Twitter on the iPad to check in on your Peeps interrupts AirPlay playback as the currently active application keeps grabbing and releasing the audio source.

There’s another way

Roon and some Google playback mechanisms work differently. The controller sets up the playback and goes about its business or leaves home.. The Roon core retrieves the media, converts it to a sample stream, and sends the samples synchronized to each destination playback endpoint. Google ChromeCast tells the endpoint what to play and it does it. I can leave home with the dogs listening to Deep House to their heart’s content. Ain’t Electronic Dance Music wonderful?

Another thing to remember is that modern devices don’t need to be spoon-fed the sample stream. My Roon endpoints have sufficient storage to buffer the entire Wagner Ring locally for playback! Time to replace streaming with staging for playback. Transfer the item to be played to a temporary file. Locally decode and deliver the sample stream to the DAC. The DAC will manage data flow and clocking (it will anyway).