In Home Theater Audio gear: short for pre-processor. In simple terms, it's the 'brains' of a home theater system. Usually a preamp for home audio systems that has the D/A converters (digital signal processing) built in and distribute the analog audio to self powered pro speakers or block amps in high end systems. Example: Marantz AV8801. Units have HDMI or USB inputs that can process the complex digital signals (ex. DTS, Dolby, etc.) and output it in RCA or XLR (analog) formats.

THE BASICS >>>>>

Block Amp - Audio amplifier with zero controls

Pre Amp - Source Selection, Audio Volume control, no amplification.

Pre-Pro - An pre amp with digital processing built in.

Integrated Amp - A preamp and block amp combined in one unit

Receiver - An integrated Amp with a tuner (Radio) and/or pre-pro built in. Everything in one box.

Pre-Pro primary functions include:

- Source selection

- Volume control

- Multi-channel digital to analog conversion

- Delays and volumes for individual speakers

- Upmixing, from 5.1 to 7.1 for example

- Bass management
Secondary Functions -

- High resolution audio format decoding

- Room correction

- Video scaling

- 2nd and 3rd zones

- Media streaming

- Internet radio
I bought an Onkyo PR-SC5509 pre-pro so I could play a bluray on my laptop, go HDMI directly from my laptop to Balanced XLR output to run my Mackie SA1532 professional loudspeakers, also run my Home Theater Receiver to get surround sound in my living room, and run another signal the outdoor speakers in the backyard as "zone 3". I was shocked when I fed the pre-pro with a 24bit, 96khz signal and as well as a DTS encoded bluray and it played it all perfectly.
by Brian Pa June 27, 2014
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