Pro Logic 2 question

[keiron99]

I always assumed that Pro Logic 2 could only be applied to digital inputs. However, playing around with my wires on my Rotel 1066 processor, I was surprised to find that I could engage Pro Logic 2 from an analogue source (I'm probably the only one who didn't realise this!) Can I correctly assume that my processor is converting the analogue signal to digital before doing its trickery to turn it into Pro Logic 2? Is there any advantage/disadvantage to applying it to the source connected via digital input over analogue input?

Also, when applying Pro Logic 2 (especially via analogue inputs), does the front left & right channel pass "unadulterated", or are those signals manipulated in any way?

[Kevin P]

DPL II is a matrix scheme that converts 2 (or more) channels to 5.1. It will work with analog or digital sources, unlike Dolby Digital & DTS which has to be passed as digital.

Most, if not all, processors convert the analog signal to digital in order to provide any form of processing, including DPL, DPL II, DSP modes, and bass management.

DPL II, as in all forms of DPL, routes signals based on relative level and phase from the front channels to the center and surrounds. Therefore, the front left & right do get "adulterated".

The advantage of going with digital rather than analog inputs with most processors is one less D/A and A/D conversion step. Where analog has the advantage is when you use an analog bypass (no processing at all) in your pre-pro with a high quality DAC on your source, or real analog sources such as a turntable.

[keiron99]

Thanks, Kevin, that explains it very well. The reason I ask is because I have been playing around with the wiring and investigating some features I haven't touched for a couple of years as a result of buying a Perpetual Technologies P3 DAC. Despite the already good quality of the Rotel, this does indeed provide superior quality stereo playback. That said, I do enjoy the effect of Pro Logic 2 on some music. Previousy since I had my source connected digitally, I would just switch between stereo and PL2. Now I have the options of applying PL2 on the digital input from my source or on the analogue input from my DAC.

I'll need to listen a little more closely before deciding!