What is the frequency cutoff for 5.1?

[polktiger]

My understanding is that when encoding 5.1 the ".1" is the low frequecy channel. My question is what frequency is the cutoff for "low frequecy?" 100hz? 80hz?

A thread below made me wonder. The poster was going to run two subs, one left, one right. Each using the appropriate speaker level in/out on the sub. I thought, why not just Y split the mono sub out from the receiver and use the LFE input on the sub. But it occured to me, that setting up that way would not result in a true left sub and right sub which could make a difference for music, but would it matter for movies. For movies, isn't all the deep bass mono via the 5.1 encoding?

[McLoki]

There really is no frequency cutoff. (most movies would not send information much above 125hz to the LFE channel though)

I think that is the reason that many companies cut the LFE channel at the same level as any small speakers crossover is at (i.e. the crossover is global including the LFE channel). (I know my NAD does - I believe that outlaw actually does it correctly though and does not cut the LFE channel at all).

Michael

[Holydoc]

My understanding is that when encoding 5.1 the ".1" is the low frequecy channel. My question is what frequency is the cutoff for "low frequecy?" 100hz? 80hz?

A thread below made me wonder. The poster was going to run two subs, one left, one right. Each using the appropriate speaker level in/out on the sub. I thought, why not just Y split the mono sub out from the receiver and use the LFE input on the sub. But it occured to me, that setting up that way would not result in a true left sub and right sub which could make a difference for music, but would it matter for movies. For movies, isn't all the deep bass mono via the 5.1 encoding?

Actually if you are just sending the low frequency, LFE, information to the sub and have the receiver set to around 80hz for sending signals to the sub, it does not matter whether you have a y splitter cable on the LFE output or set up any other way. That low a frequency does not allow you to localize the placement of the subwoofer. That is why most subwoofer companies recommend that you use a Y split. Having two or more subwoofers in that case just give you more "Omph", for lack of a better word.
:D