LFE and Speaker Cross-over settings...Different?

[Matt34]

I understand Audyssey MultEQ and some other higher end receivers allow for the LFE signal to be x-over separately from the normal speaker x-over settings? Can someone break this down for me and explain if there is truly a benefit in a system that allows you to do this?

 

[diegs]

Great question! A while back on the Denon 2808 I adjusted my LFE crossover to 90hz and left the rest of the speakers at 80hz for about a month. I didn't really notice a difference, so I set all speakers to 80hz and it sounds fine. But like you, I wonder why?

 

[mike c]

AFAIK.

the speaker crossovers are bass redirection crossovers. i.e. 80hz and below of these channels go to the subwoofers

the LFE crossover is the lowpass of the LFE channel itself. AFAIK, if you lowpass this to anything but the max of 120hz and there comes along content in that LFE channel that's above your set lowpass. the bass is not redirected ANYWHERE and you just don't hear that content.

now as to how many movies have LFE content that high? i don't know.

edit: http://www.avsforum.com/avs-vb/showthread.php?t=1141952&highlight= looks like there's a bit

 

[Matt34]

AFAIK.

the speaker crossovers are bass redirection crossovers. i.e. 80hz and below of these channels go to the subwoofers

the LFE crossover is the lowpass of the LFE channel itself. AFAIK, if you lowpass this to anything but the max of 120hz and there comes along content in that LFE channel that's above your set lowpass. the bass is not redirected ANYWHERE and you just don't hear that content.

now as to how many movies have LFE content that high? i don't know.

So a receiver like my Yamaha 663 that doesn't have this option to separately set the LFE channel combines the LFE and speaker cross over setting? Am I potentially missing out on some LFE then?

 

[mike c]

i don't think so. since there's no option to low pass the LFE channel, i guess it sends the full LFE content into the subwoofer

 

[nibhaz]

AFAIK.

the speaker crossovers are bass redirection crossovers. i.e. 80hz and below of these channels go to the subwoofers

the LFE crossover is the lowpass of the LFE channel itself. AFAIK, if you lowpass this to anything but the max of 120hz and there comes along content in that LFE channel that's above your set lowpass. the bass is not redirected ANYWHERE and you just don't hear that content.

now as to how many movies have LFE content that high? i don't know.

edit: http://www.avsforum.com/avs-vb/showthread.php?t=1141952&highlight= looks like there's a bit

+1 QFT This is my understanding of this situation as well. Personally I feel that this should not even be a user controlled feature.

 

[mike c]

+1 QFT This is my understanding of this situation as well. Personally I feel that this should not even be a user controlled feature.

it might be for the rare cases where the subwoofer is somewhere it's gonna sound very directional when 120hz content comes in.

 

[diegs]

Great info. This suggestion might be a little over-kill, but low frequency test tones would help set the LFE x-over to its optimal setting. Start with 30, 40, 50 ... until you can pinpoint where the sound is coming from, then back up LFE x-over setting 10hz lower from the test tone frequency you pinpointed the sub placement. Everybody has different rooms and subwoofer placements and even with the same equipment the LFE setting might be different.

 

[Tomorrow]

So a receiver like my Yamaha 663 that doesn't have this option to separately set the LFE channel combines the LFE and speaker cross over setting? Am I potentially missing out on some LFE then?

Matt,

If you have a subwoofer engaged in your system, all signals from the LFE (the .1) channel source are output to your Yammie subwoofer-out port only. All bass below the set subwoofer crossover point from the other 7 channels is also output to the sub.

I know of no receiver or processor that splits the LFE signal to the sub and other speakers. That doesn't mean it doesn't exist...just that I have never heard of one.

 

[pzaur]

Nice question and thread. I'm surprised this has not really come up before.

-pat

 

[Tomorrow]

I understand Audyssey MultEQ and some other higher end receivers allow for the LFE signal to be x-over separately from the normal speaker x-over settings? Can someone break this down for me and explain if there is truly a benefit in a system that allows you to do this?

I'm just guessing that what you recall is that some audyssey equipped systems have differential crossover settings. The processor has the ability to set the bass crossovers at different points for different speakers (e.g. mains at 50, surrounds at 80, rears at 100). But that has nothing to do with the LFE channel.

 

[Matt34]

I'm just guessing that what you recall is that some audyssey equipped systems have differential crossover settings. The processor has the ability to set the bass crossovers at different points for different speakers (e.g. mains at 50, surrounds at 80, rears at 100). But that has nothing to do with the LFE channel.

Even my 663 does the separate x-over points for each set of speakers but it doesn't have a separate LFE channel x-over. That is where the confusion was at.