With an AV2 / 175 / 150x combination, do you need to ensure all the speaker cable is the same length for all channels?

Rgds
Ed

This is dependant on several things:-

If you are using the same make of speakers all around, then there could be a sonic benifit in keeping the same lengths. If your surrounds are different to your fronts then it is probably not so critical.

Sub and centre are probably not so relevant as they are individual speakers.

(Bear in mind though that DD/DTS are compressed format, so there has already been quality reduction of sorts)

I wouldn't

I'd use a minimum of 3.5m per channel... beyond that I'd have an equal length pair at the front... an equal length pair at the back (not the same length - just treat it as two separate stereo pairs), and whatever's needed at the front.

In my setup I have minimum lengths across the front 3... hence 3 x 3.5m, and a pair of 9m to the rears.

Hope this helps.

Mike