Lfe question

Can someone tell me a little bit more about lfe output. I have a denon 3808ci avr and I'm not sure if I should have it set to LFE or Lfe plus main.

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Answers

  • befuddle
    befuddle Posts: 126
    LFE [low frequency effect] allows you to choose if you want the bass to be directed to both the sub and main spks or just the sub.Choosing just the sub allows the AV amp to work easier since it takes more power to drive the low frequencies,which can instead be done by the sub's amp.
    In the sound menu setting the all the speakers to small also directs the lower bass to the sub.The term large means the full frequency range [high/mid/lows] not the spk. size.This is the usual recommend setting when using a powered sub.
  • befuddle
    befuddle Posts: 126
    edited November 2016
    Also if you don't have access to the manual try googling the brand name model num and manual most of them are online. Although sometimes you may have to go through some web pages to find them.
  • WTS
    WTS Posts: 170
    nhhiep wrote: »
    I've this same AVR. if you have big full range main speakers and want to run them full range, then set to LFE. Otherwise, set to LFE+Main and select your crossover point.

    In my case, I set my Polk 707s as Small with Crossover at 80hz. Set LFE+Main, so all the bass under 80hz from my mains go to the SVS SB13U sub.

    Question: if you set your 707s for an 80hz crossover, what advantage is there to have the 707s, vs. 703s?
  • pkquat
    pkquat Posts: 742
    All the above are correct, that if you have a sub, let it do the Low Frequency Effects (LFE) work. LFE is hard on AVR amps and most "full range" speakers struggle with them. LFE often contain frequencies that are more to be felt than heard, and out of the range of most full range speakers.

    "Large" means your main speakers will see the full range of the L + R channels. "Small" means the sub will handle L + R frequencies below the crossover off point on the AVR. The LFE frequency range is 3-120Hz, and it is mono. There is no real benefit to adding it to your mains.

    I used LFE+Main when I did not have a sub, but I had an external amp. Even so kept the volume lower, and I also ran the signal through another piece of equipment that had a subsonic filter to eliminate the "rumble only" frequencies the speakers had no chance of being able to reproduce.
  • nhhiep
    nhhiep Posts: 877
    WTS wrote: »
    Question: if you set your 707s for an 80hz crossover, what advantage is there to have the 707s, vs. 703s?

    2 woofers in the 707s are crossed at a much higher hz, something in the 200-300hz. So they're still active.
    Plus, quality stands for the 703s are very expensive.
    and the 703s aren't loud enough for my 2700sq space.
    and I like big towers :)
  • Erik Tracy
    Erik Tracy Posts: 4,673
    edited November 2016
    Try it both ways.

    See what you like.

    The OP didn't mention what sub he has or what speakers.

    Just cuz you have a sub doesn't mean it is any better than the fronts for bass.

    For movies with scary LFE, ok, sure - neuter your mains and set them to small and the xover to 80hz.

    For music - maybe set the sub to off, maybe set the the bass to be LFE+mains(set to large)...


    H9: If you don't trust what you are hearing, then maybe you need to be less invested in a hobby which all the pleasure comes from listening to music.
  • WTS
    WTS Posts: 170
    nhhiep wrote: »
    WTS wrote: »
    Question: if you set your 707s for an 80hz crossover, what advantage is there to have the 707s, vs. 703s?

    2 woofers in the 707s are crossed at a much higher hz, something in the 200-300hz. So they're still active.
    Plus, quality stands for the 703s are very expensive.
    and the 703s aren't loud enough for my 2700sq space.
    and I like big towers :)

    Thanks for the input.

    The 707s are louder than the 703s? I assumed they'd be just deeper, not louder. No? I haven't heard the 707s. I have heard the 703s.

    If you would, please elaborate on the "quality stands" comment.
  • tonyb
    tonyb Posts: 32,902
    I think what he means by "quality stands" is, stands whose beauty and stability match those of the speakers. You don't want to put bigger beautiful bookies on Walmart stands....know what I'm sayin' ?
    HT SYSTEM-
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    Polk Sig. 20's
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    Acoustic zen Satori speaker cables
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  • nhhiep
    nhhiep Posts: 877
    yes, I meant good looking and solid stands for the 703s are expensive. even then, any kid can push over a stand, where the 100lbs 707 needs 2 adults to even move it.

    I know on paper, they're both 88dB sensitivity, but to my ears, the 707s are fuller, even when xover at 80hz
  • WTS
    WTS Posts: 170
    Thanks for the input.