1. Guest,
    If you need help getting to know Xenforo, please see our guide here. If you have feedback or questions, please post those here.
    Dismiss Notice

LFE Question

Discussion in 'Speakers' started by BraveHeart123, Jan 23, 2013.

  1. BraveHeart123

    BraveHeart123 Well-Known Member

    Joined:
    Oct 5, 2010
    Messages:
    271
    Likes Received:
    0
    Can anyone list some movies that have strict compliance to movie recording levels especially the LFE part? Some movies, e.g. Taken-1 has exeggerated LFE and I don't think it conforms to the loudness standards. The gunshots, though, sound great but are unreal. One more thing.....0dBFS means 105dB SPL on the speakers, but what about the same for LFE, which is already 10dB hotter?? Going by the book, the processor should clip any signal that's greater than 105dB SPL. If so, how does clipping kick in??? I am asking this coz um using BFD to tame the sub response and I am not too sure how it handles LFE that is already 10dB (115dB) hot when mains are playing at peak reference level (105dB)? Does BFD adjust itself for the bass frequencies and let the signal go unclipped till 115dB SPL or (120dB SPL including the redirected summed up bass from all the channels)?? I hope I've clearly stated what I need to clarify. Any thoughts on this??
     
  2. Robert_J

    Robert_J Well-Known Member

    Joined:
    Aug 22, 2000
    Messages:
    8,264
    Likes Received:
    46
    Location:
    Mississippi
    Real Name:
    Robert
    All movie gun shots are unreal. There's very little bass in a real shot. http://s3.photobucket.com/albums/y78/rlj5242/AR-15/?action=view&current=100_2776.flv
    Don't think of the BFD in terms of in-room SPL. The box has no idea how loud your room is. It just passes an electrical signal and adjusts it based on the filters you set. I wouldn't worry unless your BFD's level meter is getting into the yellow or red area. Mine barely moves past the first green bar.
     
  3. Dave Upton

    Dave Upton Owner
    Owner

    Joined:
    May 16, 2012
    Messages:
    2,327
    Likes Received:
    215
    Location:
    Houston, TX
    Real Name:
    Dave Upton
    My answer is extremely unscientific as I don't have waterfall plots to back this up - but Battle: LA has some incredibly realistic bass that doesn't run too hot.
     
  4. Robert_J

    Robert_J Well-Known Member

    Joined:
    Aug 22, 2000
    Messages:
    8,264
    Likes Received:
    46
    Location:
    Mississippi
    Real Name:
    Robert
    The last time I was there during an alien invasion, I said to myself "This sounds just like a movie I watched." Seriously, that movie does have some realistic sounding M4 / ACR rifle sounds.
     
  5. BraveHeart123

    BraveHeart123 Well-Known Member

    Joined:
    Oct 5, 2010
    Messages:
    271
    Likes Received:
    0
    Hi Robert, if you are getting only the first green bar lit on BFD then you are at -40dBFS (65dB SPL). I assume, then, u must be dialing your ep2500 way way way up to get upto 115dB on LFE when your mains are hitting the full scale reference peaks of 105dB. Can you pls tell as to where your subwoofer trim level is on the avr??
     
  6. Robert_J

    Robert_J Well-Known Member

    Joined:
    Aug 22, 2000
    Messages:
    8,264
    Likes Received:
    46
    Location:
    Mississippi
    Real Name:
    Robert
    I haven't checked in years but I think the AVR is set at +3 and the EP-2500 is 2 detents from all the way up.
     
  7. BraveHeart123

    BraveHeart123 Well-Known Member

    Joined:
    Oct 5, 2010
    Messages:
    271
    Likes Received:
    0
    its odd coz mine is at -3 and FL and FR are at 00 on avr. I manage to hard-hit the clipping lights on BFD at reference volume on some movies e.g. first car explosion scene in Killer Elite. What are your mains (FR/FL) set at on the level trims?
     
  8. Robert_J

    Robert_J Well-Known Member

    Joined:
    Aug 22, 2000
    Messages:
    8,264
    Likes Received:
    46
    Location:
    Mississippi
    Real Name:
    Robert
    I'll see if I can find some time to connect a monitor to the receiver and see my settings. I may have to go back and revisit Battle: LA and see if I can push the BFD into the warning area.
     
  9. BraveHeart123

    BraveHeart123 Well-Known Member

    Joined:
    Oct 5, 2010
    Messages:
    271
    Likes Received:
    0
    I just wana check the relative trim levels of mains wrt sub. Pls send this info whenever you can. thanx
     
  10. BraveHeart123

    BraveHeart123 Well-Known Member

    Joined:
    Oct 5, 2010
    Messages:
    271
    Likes Received:
    0
    Just watched different scenes from Battle LA. You r right, it has some of the best and most realistic LFE mix in it. Um running dual stacked subs that dig only till 22hz. The business area in this movie is mostly below 30Hz and a lot many times i think it plummets way below 20Hz. I guess I'd have to fire up my iNuke 6000 dsp and add my third DIY sub that goes till 16Hz. One odd thing though.....The last scene when the alien ship lifts off the ground, there is a tremendous subsonic impact. But there is not even half the same when the last missile hits it and blows it up. I was expecting bigger and stronger shockwaves. I think that should have been the other way around. Overall one of the best and most realistic war LFEs mixed in any movie.
     
  11. BraveHeart123

    BraveHeart123 Well-Known Member

    Joined:
    Oct 5, 2010
    Messages:
    271
    Likes Received:
    0
    Can somebody answer as to how BFD handles LFE signal. 0dBFS is 105dB peak, but that is for the mains. How does BFD handle LFE signal that is 115dB when speakers are playing Peaks at 105dB? Going by the book, it should clip anything hotter than 105dB max. But actually it should not or it will nagate the whole purpose of seperate 10dB hotter LFE mix. Need clarification.
     
  12. Dave Upton

    Dave Upton Owner
    Owner

    Joined:
    May 16, 2012
    Messages:
    2,327
    Likes Received:
    215
    Location:
    Houston, TX
    Real Name:
    Dave Upton
    Clipping has nothing to do with the digital level (dBFS) as far as the BDF is concerned. You're sending the BFD an analog signal which is essentially voltage and current. As long as the level meter on your BFD isn't stuck in the red all the time, you're in good shape.
    Here's an excerpt from the BFD Guide referencing setting levels:

    Quote:
     
  13. BraveHeart123

    BraveHeart123 Well-Known Member

    Joined:
    Oct 5, 2010
    Messages:
    271
    Likes Received:
    0
    I already went through this article a long time ago. Anyway, I didn't get it when you say clipping is nothing to do with digital level. What is the point of signal processing and reference listening then?? Some movies do kick the bass into red clipping zone on BFD at -10dBFS on master volume.
     
  14. Robert_J

    Robert_J Well-Known Member

    Joined:
    Aug 22, 2000
    Messages:
    8,264
    Likes Received:
    46
    Location:
    Mississippi
    Real Name:
    Robert
    Sounds like you need an additional sub(s) so that you can have the volume you want without pushing the BFD into clipping.
     

Share This Page