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post #1 of 15 Old 06-23-2014, 05:20 AM - Thread Starter
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Bass from mains or lfe?

Not sure if this is the correct forum but; Is there a difference in audio content between listening to music/movies and having the bass directed through your mains LR speakers as opposed to the LFE channel? Assuming mains are large enough to play fairly low. If you were listening to a concert dvd, would much/any of the content come through the lfe channel or is lfe simply a steeply sloped LP crossover?
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post #2 of 15 Old 06-23-2014, 05:31 AM
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That all depends on what you've set crossovers to.

I use small 70hz for front three and sides, 120hz for rears. So <70z from front three and sides gets re-direct to the sub, <120hz from the rears to the sub, and I use 70hz crossover on the Lexicon so no bass above that is reproduced. I don't believe bass is "lost" as I know LFE includes upto 120hz, so I think 70-120hz bass is re-directed to mains.

Also depending on bass managment, your sub should still output bass even when listening to 2 channel, or 5.0 mix, if bass management is enabled and running small.

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post #3 of 15 Old 06-23-2014, 07:15 AM
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LFE is a specific channel, the .1 in a multichannel system. Bass management redirects low frequencies from full range speakers to the sub(s). As a general rule, bass management will provide better overall response, even when the L/R mains are capable of low frequency playback, because the front speakers must be positioned for imaging, which may not be optimal for bass response. But, this is very much dependent on the room and equipment.

As for LFE itself, it's really a channel designed for movies, where effects like explosions will be heard over everything else. While a multichannel concert mix may have content in the .1 channel, it's likely no different than you would get using bass management with a 5.0 mix.
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post #4 of 15 Old 06-23-2014, 09:39 AM
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Quote:
Originally Posted by mrevo2u View Post
Not sure if this is the correct forum but; Is there a difference in audio content between listening to music/movies and having the bass directed through your mains LR speakers as opposed to the LFE channel? Assuming mains are large enough to play fairly low. If you were listening to a concert dvd, would much/any of the content come through the lfe channel or is lfe simply a steeply sloped LP crossover?
There is another option. Most receivers have a function that adds the stereo bass content to the LFE channel. You can have bass coming from both your mains and your sub. Few people recommend it including me but I actually do it that way for reasons I won't go into here. So you can have the mains handle all the bass, the sub handle all the bass or both.
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post #5 of 15 Old 06-23-2014, 10:35 AM
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Quote:
Originally Posted by mrevo2u View Post
Not sure if this is the correct forum but; Is there a difference in audio content between listening to music/movies and having the bass directed through your mains LR speakers as opposed to the LFE channel? Assuming mains are large enough to play fairly low. If you were listening to a concert dvd, would much/any of the content come through the lfe channel or is lfe simply a steeply sloped LP crossover?
I have never heard a situation in my own setups where the use of a powered sub to handle bass was not an improvement. There might be very high quality floorstanders that have no problems putting out clean sounding 30hz bass at a suitable level. But I have not owned them.

Everytime I remember turning off bass management and listening to the system with it off, bass was less defined (if you prefer more muddy.)

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post #6 of 15 Old 06-23-2014, 02:01 PM
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Quote:
Originally Posted by MichaelJHuman View Post
I have never heard a situation in my own setups where the use of a powered sub to handle bass was not an improvement. There might be very high quality floorstanders that have no problems putting out clean sounding 30hz bass at a suitable level. But I have not owned them.

Everytime I remember turning off bass management and listening to the system with it off, bass was less defined (if you prefer more muddy.)
+1. In my purely personal experience, when bass sounded muddy, it was because the sub was too loud. To my ears, on overhyped sub channel even sounds like it's playing too slow - - like it's a bit behind the rest of the sound. It's probably often only one or two untamed response peaks that cause the problem, but simply calibrating the sub so it works for you can make a huge difference. Too much can, at least for me, turn it all to crap.

And FWIW, there are no rules on how much bass is mixed into the actual LFE channel (ie the .1 of a 5.1 or 7.1 mix) so you just cannot make broad statements about where the bass lives on any given mix. Seems fairly clear that most movies put a lot into the left and right as well as into the LFE channel. In case that was one of the questions you intended to ask.
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post #7 of 15 Old 06-23-2014, 10:15 PM - Thread Starter
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Thanks for the responses; more involved than I thought. Goal is to run 4 sealed Dayton 15's for the low end of my mains (would split the LR signal). I envision this with concert dvd's or when my wife picks the movie. This way I can get 99% of the recording even if I don't turn on the subs (4 ftw21's) which will obviously be on lfe channel. Just wanted to make sure I wouldn't be missing out recorded content going one way or the other.
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post #8 of 15 Old 06-24-2014, 12:05 AM
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Originally Posted by fatbottom View Post
That all depends on what you've set crossovers to.

I use small 70hz for front three and sides, 120hz for rears. So <70z from front three and sides gets re-direct to the sub, <120hz from the rears to the sub, and I use 70hz crossover on the Lexicon so no bass above that is reproduced. I don't believe bass is "lost" as I know LFE includes upto 120hz, so I think 70-120hz bass is re-directed to mains.

Also depending on bass managment, your sub should still output bass even when listening to 2 channel, or 5.0 mix, if bass management is enabled and running small.
Not sure what "the Lexicon" is but normally bass doesn't get redirected from the subwoofer channel back to the mains if bass management is used nor does the subwoofer low pass apply to the summed response but to the LFE channel only. Signal flow looks something like this:

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post #9 of 15 Old 06-24-2014, 12:09 AM
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Quote:
Originally Posted by mrevo2u View Post
Not sure if this is the correct forum but; Is there a difference in audio content between listening to music/movies and having the bass directed through your mains LR speakers as opposed to the LFE channel? Assuming mains are large enough to play fairly low. If you were listening to a concert dvd, would much/any of the content come through the lfe channel or is lfe simply a steeply sloped LP crossover?
http://www.genelec.com/faq/multichan...lfe-1-channel/

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post #10 of 15 Old 06-24-2014, 03:23 AM
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That's what Lexicon said. I don't like LFE set to 120hz, in the setup you can alter the subwoofer crossover, which is great for music, as 120hz is way too high.

If you set subwoofer to say 40hz, then not much bass comes from it. Hopefully it gets re-directed to 5.0 speakers, although I have no way to test this, but they said it does get re-directed.

It's a Lexicon MC-8.

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post #11 of 15 Old 06-24-2014, 03:40 AM
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^
Just checked the manual. Their implementation is a bit weird:

"In a custom setup, low frequencies are generally redirected from speakers with the highest crossover points to speakers with the lowest crossover points. Signals lower than the lowest crossover point are redirected to the subwoofer. If the lowest crossover point is FULL, low-frequency signals, excluding LFE information, are not redirected to the subwoofer."

So if you set surrounds to 120Hz and mains to 60Hz then 60-120Hz from the surrounds is sent to the mains. What is sent to the sub? <60Hz or <120Hz?


"SUBWOOFER
Assigns a crossover point for the Main Zone audio output connector labeled Subwoofer. When set to FULL, the MC-8 sends a full-range audio output signal to this connector. Otherwise, the MC-8 activates a crossover point at the selected setting. Choose the setting equal to the lowest setting of the other speakers."

There indeed seems to be a low pass that is applied to the summed subwoofer feed. Weird. The device is pretty old though. Guess they didn't know better at the time.

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Last edited by markus767; 06-24-2014 at 03:46 AM.
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post #12 of 15 Old 06-24-2014, 03:50 AM
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The "correct way"

Set speakers to 80hz
subwoofer to 120hz

I don't like subwoofer to 120hz though.

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post #13 of 15 Old 06-24-2014, 08:49 AM
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Quote:
Originally Posted by mrevo2u View Post
Thanks for the responses; more involved than I thought. Goal is to run 4 sealed Dayton 15's for the low end of my mains (would split the LR signal). I envision this with concert dvd's or when my wife picks the movie. This way I can get 99% of the recording even if I don't turn on the subs (4 ftw21's) which will obviously be on lfe channel. Just wanted to make sure I wouldn't be missing out recorded content going one way or the other.
Seems like an odd setup. You are going to build your own crossover so you can pair two subwoofer to the left channel and two to the right? Or something like that?

Why not just setup one to two powered subwoofers, connect them to the subwoofer channel and use bass management? This is often suggested for a few reasons. A powered sub, having it's own amplifier can take some load off the receiver. You can use the receivers own bass management to send the sub channel both the LFE from movies and bass from ANY source. This is the simple, reliable and the usual way to handle bass in a modern setup.

Not sure why you are thinking of running 4 subwoofers. Two is a pretty good compromise as you can even out the bass response in a room better with two, but most people use one. But I am not sure exactly what you meant, so I may be off target.

In my setup, I run two powered subwoofers, one in the front corner, one in a rear corner, and I either split the subwoofer output with a Y jack, or my receiver has two subwoofer outputs. Not e that few receivers seem to have the ability to separately apply their room correction system to two subwoofers.

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post #14 of 15 Old 06-24-2014, 08:59 AM - Thread Starter
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Actually 8 subwoofers in a .2 configuration all off JBL synthesis amps and a peavey 7500ipr. Goal is to have four 15's crossed actively to the main LR channels and the 4 ftw21's on the lfe channel. Although on the Anthem D2, I can run all on the lfe outputs.
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post #15 of 15 Old 06-24-2014, 01:25 PM
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It may work out very well, never tried anything like that. Just seems, to me, overly complicated when modern receivers can handle all your bass management needs, avoiding a need for bass handling at the LR speakers. I always thought all you need were one or two subwoofers with sufficient power for the desired SPL and suitably low FR.

Hope it works out well for you.

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