Details of CNBC's music streaming test: How it worked

Our main article described the basic setup and results of our music streaming test.

But we know a lot of our high-end audiophile readers will have questions about the specifics of what we did. For those people, here are the details. Note again that this is not a scientific test, but rather an informal way of replicating what normal consumers would do: listen to the same song on a few different services, to see what sounds best.

We conducted our test in CNBC's high-fidelity audio "sweetening" room. Professional audio engineers set up all the equipment and operated the tests.

We brought in 15 of our colleagues, asking them to pick three songs each. That got us to 45 total songs played. A few of the colleagues wanted to try a fourth song, so that's how we ended up with 48 possible picks.

Each song was played on three streaming services. Tidal was the high-fidelity choice, along with Spotify and Apple Music. If Spotify or Apple Music happened to crash a browser temporarily, then we swapped in Deezer to ensure that there were always three choices. Tidal never crashed, so that one was always an option.

CNBC

CNBC conducting audio tests: can people hear high fidelity?

Each song was selected by the listener. We did not pick the songs for them. That way, it would replicate how a normal user might use a streaming service, by picking the songs they actually want to hear. That contrasts with other, scientific tests that force listeners to only listen to certain songs of a genre, like classical or jazz.

The participants did not know which service they were listening to at any given time, because we randomized the order of how we played them. The randomization also prevented one participant from trying to tip off future test subjects in trying to guess the answer correctly.

The participants were about evenly split between male and female, and ages ranged from 21 to 55.

The choices of music included a variety of all genres: classical, jazz, rap, rock, alternative, metal, country, pop. The songs also came from a variety of decades: going back to the 1960s and as fresh as today's hits.

CNBC

CNBC conducting audio tests: can people hear high fidelity?

Each person listened to the song, facing away from the computer, so they couldn't see what was played. The participants had as much time as they wanted before they told us that they wished to move on to the next song.

After all three versions of the same song were played, they tried to guess which of the three had been the high fidelity one. We told them the exact result, and then continued on with the next songs.

The speakers were facing the participants. The internet connection was a hardwired landline connection, so there wouldn't be any reductions in streaming quality due to wireless issues.

Tidal runs at a "lossless" 1,411 kbps streaming rate. Spotify and Deezer (along with Google Music and others) run at 320 kbps. Apple Music streams at 256 kbps, but this uses a different file format known as AAC, which is more efficient than MP3, packing in more sound quality while taking up less storage space.