Types of PCM

LPCM Mono is for audio for only one sound channel, left or right. The other channel will be quiet. Mono audio is uncommon today in favor for stereo, but it is still used for artistic reasons and simplified purposes, mostly for music and movies for it's simplicity. Filmmaker, Stanley Kubrick, preferred Mono because it's easy and basic to mix with. 

LPCM Stereo is for audio with 2 sound channels. Stereo speakers, soundbars and headphones are quite common for consumers. Casual consumers who watch movies and TV would use built-in TV speakers and soundbars. Gamers often use stereo speakers for PC and professional headphones, but also soundbars and speakers.

If you a person who doesn't care about surround sound, then stereo is the option for you.

There's technologies like QSound and Roland Sound Space to create an advanced version of normal stereo with illusional depth and increased dynamic range without the need of additional speakers.

Stereo is often common with Audio CDs.

PCM 4.1 uses two additional channels. It's rarely used today, but it was used for older films and Laserdisc analog/digital tracks. Example, Alien 1979 was originally in 4.1. 

3.1 is extremely rare, and there's no point of using because it has the same sound as stereo.

Introduced in the 1970's, PCM 5.1 offers 3 additional speakers to create an surrounded and dynamic space. 5.1 is the standard and most common surround sound setup for movies, TV and video games.

 Filmmaker, Christopher Nolan, chooses 5.1 as his preferred sound mix and takes artistic advantage of it. 5.1 is also the standard surround sound audio component of digital broadcast and music.

Blu-ray  Audio offers 5.1 uncompressed PCM sound that has greater bitrate and frequency than Audio CDs.

6.1 adds an additional channel on the back to give a more immersive sound in the backside. Common during the late 90's and 2000's.

Introduced in 2010, 7.1 surrounds adds an additional channel your room with maximum sound space and information to give you an immersive experience like your in the movie. This set up is more common than 6.1.

Rarely used for PCM. This is the max sound channels for Blu-ray Disc.

Video games will use a non-linear system to provide realtime spatialization (adaptable sound location) to extend the playing experience. It can be used for Stereo or Surround sound.

There is no unified logo for PCM, and the original "digital sound" logo's copyright status in unknown so we made open-source PCM logos for ANYONE to use for commercial use under the Creative Commons Attributions 4.0 license. https://creativecommons.org/licenses/by/4.0/