I was just wondering if a powered sub is connected to a reviever via a speaker level output dedicated to LFE, will the sub be putting a strain on the revievers amp or will it simply be using that signal to reproduce the LFE channel?
Good question. I haven't really done any measurements but I would think that it will still be using that power since the signal is stepped down when it gets to the subwoofer.
Well you can measure the output from the Baby Boom channel (LFE.1) at its output connection with a volt meter, I would recommended using one with digital display, rather than one with an analogue readout, with the digital meter you will be able to see the decimal point which will make far easier.
Once you have checked the out from the AVR's Baby Boom channel (LFE.1) output, connect the RCA phone lead to it, and recheck it at the end of the lead, if there is a slight drop in output, it really shouldn't affect the performance.
If you what you can do the same with checking all three screen channels and split-surrounds, at the crossover point, LOL, but I'd rather stick to the old way of using a SPL db meter and RTA analyser, but if you have an oscilloscope and wanted to get really, and deeply involved with this task, be guest.