What Chris describes above is what we use in broadcast transmission. Multiband compression and limiting in our Optimods typically splits into 5 bands in which individual eqs can be tweaked and different compression and limiting applied before remixing into a single feed for the transmitter at which stage Brick wall limiting is applied for transmitter protection.
These multiband or discriminate audio processing techniques were conceived in the 60s in the recording studio environment and then applied to broadcast. Below is an excerpt on Mike Dorroughs development of the concept and invention of the first Multiband Compressor or as he called it DAP-310 Discriminate Audio Processor.
" Mike Dorrough grew up with a love for radio and an insatiable desire to understand how sound devices worked. As a young man in the early 1960's Mike worked for a recording company owned by Casey Kasum and Bob Hudson, as a sound mixer. During that period he devised a revolutionary multi-band or DISCRIMINATE AUDIO PROCESSING method that provided greater loudness with no reduction in fidelity through achieving optimum relationships between FREQUENCY, TIME and AMPLITUDE in the complex waveform. The system worked so well it helped to make Dorrough a much sought-after sound engineer, leading to a position with the legendary Motown in Detroit. He left Motown for RCA in the mid-sixties with high hopes of employing his prototypes in even more diverse recording environments. Continuing to refine the concept, it didn't take Dorrough long to realize that his system had even greater implications for broadcasters and in 1965 one of his first Multi-Band Composite Audio Processors was installed at KGFJ. The improvement in perceived loudness was spectacular. Shortly thereafter he left RCA for KRLA in Los Angeles. It became clear by 1971 that Mike would have to set up his own factory to produce the unit. With the able assistance of his wife Kay, Mike launched "Dorrough Electronics". By 1975 a new technical lexicon defined a whole new "audio culture". Terms used widely in the audio field today, like "Multi-band Processing", "Psycho-Acoustics", "Relative Audio-Power to Peak Amplitude", and "Sound-Density" were coined, or first popularized by Dorrough to describe the effects and benefits of the Discriminate Audio Processor"
Some reading material here
http://www.dorrough.com/mike.htmland here
http://www.dorrough.com/dorrozeum.htmlMike and I correspond occasionally about Vintage Broadcast console restoration, he has an impressive collection of early Gates, Collins, RCA and Altec broadcast consoles, compressors, limiters and transmitters