In discrete quadraphonic systems, all four channels remain fully independent of each other throughout the entire recording and reproduction chain.

These improvements included phono cartridges with higher compliance, lower distortion levels, wider frequency range, and new vinyl compounds for records.

Successful CD-4 playback in 4 channels requires a phono cartridge that can reproduce high frequency range carrier signals that extend well beyond normal human hearing.

A typical high-performance CD-4 system would include a turntable with a CD-4 compatible phono cartridge, a CD-4 demodulator, a four-channel amplifier (or receiver), and four identical full-range loudspeakers.

Simply put, CD-4 consists of four recorded signals (LF, LB, RB, RF) using a coding matrix similar to FM broadcast stereo multiplexing.

In the CD-4 system, the quadraphonic audio was divided into left and right channels, which were recorded orthogonally in the vertical plane of the disc groove, which is the case with normal stereo.

[6] The algebraic addition and subtraction of the sum and difference signals would then yield compatible and discrete quadraphonic playback.

The CD-4 encoding/decoding matrix: In October 2018 Pspatial Audio introduced software decoding of CD-4/Quadradisc recordings without the need of a specialized hardware demodulator.