What is LFE on centre speaker?

Discussion in 'AV Receivers & Amplifiers' started by gordiegords, Jun 8, 2009.

  1. gordiegords

    gordiegords
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    Hey folks, i have recently upgraded my centre speaker from a crap obne to a decent one, whaferdale cs, I notice now that on my amplifier when i watch a movie in 5.1 that the letters LFE appear above the centre speaker icon on the amp, is this something to do with bass? i have set my centre speaker to larger, would that be right? is it something to do with where the bass is sent to? i'm sure the bass on my left and rights are not as powerfull now, which i dont really like.

    can anyone shed some light?
    cheers

    Gordie :D
     
  2. dante01

    dante01
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    The LFE isn't in relation to the centre speaker, it represents the Low Frequency Effects channel present in 5.1 encoded material. The LFE channel is sent to the sub and is the .1 channel in a 5.1 discrete encoding.

    The LFE light will only be present when you play material with the LFE channel encoded in it.

    Do you have a sub? If so, set your speakers to small so that the low frequencies are sent to the sub. It is unlikely that your speakers can reproduce the lower frequencies a sub can produce.
     
    Last edited: Jun 8, 2009
  3. Mark.Yudkin

    Mark.Yudkin
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    Only if you have a large enough centre - meaning that you can't see the TV ;) Set it to small.

    The physical location of the shiny LFE indicator is not related to the physical speaker layout.
     
  4. dante01

    dante01
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    SMALL and LARGE settings have no relation to the actual physical size of the speaker cabinets. LARGE refers to the frequency range a speaker is able to handle and reproduce. In the case of the Wharfdale cc, this would be 80Hz - 24,000kHz, meaning if it were set to LARGE then frequencies being sent to it below 80Hz would be lost. If you set the speaker to SMALL then you also need to modify the crossover settings for it on the amplifier. The crossover point should be set to 80Hz, this will ensure that the frequencies below 80Hz are sent to the speakers set to LARGE or are sent to the subwoofer if one is attached. If you've other speakers set to LARGE, check to see what their actual frequency response range is and set the speakers as SMALL with an appropriate crossover setting.
     
  5. gordiegords

    gordiegords
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    o thats interesting, does that explain why i'm feeling a lack of bass? because i have the centre speaker set to larger then everything under 80 is lost? so tonight i will change the centre speaker to small, my left and rights are allready set to larger so i just need to double check that crossover is set at 80, is thats right?

    thanks

    Gordie
     
  6. Mark.Yudkin

    Mark.Yudkin
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    .
    "Large" actually means you can achieve 20hz - 20kHz at 105dB with no more than -3dB drop at 20Hz.

    Most so-called full range speakers claiming 20hz - 20kHz are making that claim at much lower volume levels (automatic setup measures at 75dB). The physical cabinet volume needed to achieve 20hz - 20kHz at 105dB is not only not "small", it is in fact very LARGE. Most physically large speakers cannot in fact achieve "Large" peformance, so that there are very few cases in which the "large" setting is correct, and as a general rule of thumb, all speakers should be set to small.
     
  7. gordiegords

    gordiegords
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    Hmmm ok, i will set to small tonight, i cant set my left and right speakers to small as the amp wont let me, i think it is because i do not have a sub installed.
     
  8. dante01

    dante01
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    Unless you've not got a subwoofer!


    If no sub is present, those speakers set to SMALL send their lower frequencies to the most appropriate speakers set to LARGE. The receiver doesn't usually allow you to set the front stereo pair to SMALL unless you set other speakers to LARGE. If you set the centre to LARGE, the front pair and rears to SMALL, all low frequencies would be directed to the centre speaker.

    gordiegords,

    What is the frequency range of you front two speakers?
     
    Last edited: Jun 9, 2009
  9. gordiegords

    gordiegords
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    Hmm this is getting interesting, i'm not that clued up about hertz, and mhz and all that stuff, i can tell you what i have got though and hope it helps.

    wharfedale diamond bookshelves 9.2 fronts.
    wharfedale centre diamond c.s

    the rears are rubbish so no need to worry about them.

    i have the left and rights on the small speaker setting and the centre on large speaker setting, i take it that is why i receive alot of bass through the centre speaker? which might i add i'm not keen on, i would prefer the bass going through the left and rights.

    thoughts?

    gordie
     
  10. dante01

    dante01
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    Set the Wharfdale stereo pair to large and the centre and the rears to small.

    The Wharfdale Diamond 9.2s have a frequency range of 45 - 24,000Hz

    You may want to adjust the crossover of the centre and rears in order to get the best results.
     
    Last edited: Jun 9, 2009
  11. gordiegords

    gordiegords
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    i made a mistake there, its the 9.1's i have, still the same frequency range?

    So if i set fronts to large (which i dont think i have an option) and set centre to small, then i will get the bass back in the fronts?

    That would be good

    Gordie
     
  12. dante01

    dante01
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    Yes, and you will have the option to set the fronts to LARGE. The only option denied to you if you've no sub is that of setting all speakers to SMALL ;)


    The Diamond 9.1 speakers have a response of 50 - 24,000Hz
     
  13. gordiegords

    gordiegords
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    Thats great mate thanks for that, so do i need to set the crossover? i have seen that menu in the settings before.
     
  14. dante01

    dante01
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    Yes, but only for the centre and the rears (set to SMALL). Set them to 80Hz and all frequencies below that figure that would normally be going to the centre and rears will then be sent to the front pair (set to LARGE).
     
  15. gordiegords

    gordiegords
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    Great mate i'll try that tongight, hopefully will be easy enough.

    Gordie
     
  16. gordiegords

    gordiegords
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    While i'm here, what does the LFE icon represent? some kind of low frequency yes? I have never noticed it until i fitted the centre speaker, i notice on the amp there is a menu to alter the LFE on hp and sp but i have no idea what that means.
     
  17. dante01

    dante01
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    Multichannel audio encoded material such as DTS and Dolby Digital 5.1 come encoded with a specific channel for Low Frequency Effects. This channel is the .1 associated with 5.1 or 7.1 discrete formats. The LFE light is showing you that the amp detects the presence of this channel in the audio stream being sent to it. 5.1 is 6 channels of audio data, one of those channels being the LFE channel.
     
  18. Mark.Yudkin

    Mark.Yudkin
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    Your Wharfedales do not support 20Hz at any volume, or even an octave above 20Hz, and are therefore small by definition (their physical size is irrelevant). Let you sub do what your sub was made to do, instead of trying to get your fronts to do what they were never designed to do. Unless of course you have no sub, in which case set the fronts to large - you won't be able to reproduce most of the LFE channel anyway.

    As dante01 says, LFE is Low Frequency Effects (earthquakes, stampedes, etc). The idea was that you'd send the LFE to a sub and the other channels to their corresponding speakers. The idea was of course flawed - few people had 5 speakers with full bass handling, so A/V amps added bass management to permit redirection of the non-LFE bass (from any channel) to the sub when it was lower than a configurable cross over. The other issue is that not everybody has a sub, so the LFE needs to be redirected to other speakers. The result is that there is no longer any fixed relationship between LFE, bass and the subwoofer.
     
    Last edited: Jun 10, 2009
  19. dante01

    dante01
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    He hasn't got a sub.
     
  20. gordiegords

    gordiegords
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    i have changed the crossover level to 80 hz and i feel now most of the bass is being sent to the fronts which i prefer although now that i have a decent centre speaker i'm not sure that i like it as much as i thought, for me it kinda takes the glory from the the two fronts, i feel alot of the sound seems to go through the centre it's almost like it takes the shine of the fronts, I dont suppose there is a way to get more from the fronts apart from turning there level up but i think if i do that i will maybe struggle to hear the dialogue, maybe it will just take me a while to get used to it, the crap centre i have before basically just threw out speech and very little else. :cool:

    any thoughts?
    Gordie
     

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