Why do so many recievers have fixed crossovers?

Discussion in 'Archived Threads 2001-2004' started by Kelly Scott Rickards, May 25, 2001.

  1. Kelly Scott Rickards

    Kelly Scott Rickards Stunt Coordinator

    Joined:
    Jan 26, 2000
    Messages:
    225
    Likes Received:
    0
    Trophy Points:
    0
    I have noticed that a small minority of recievers have adjustible crossovers (sony, outlaw)
    Do you think companies like Denon or Onkyo will ditch the 80Hz Xover anytime soon?
     
  2. Patrick Larkin

    Patrick Larkin Screenwriter

    Joined:
    May 8, 2001
    Messages:
    1,759
    Likes Received:
    0
    Trophy Points:
    0
    What does the 80Hz Denon crossover mean? Does that mean the crossover setting on the sub is rendered useless? Does it mean the receiver sends EVERYTHING below 80Hz to the Subwoofer no matter what?
     
  3. Jeremy Hegna

    Jeremy Hegna Supporting Actor

    Joined:
    Nov 28, 2000
    Messages:
    812
    Likes Received:
    0
    Trophy Points:
    0
    "What does the 80Hz Denon crossover mean? Does that mean the crossover setting on the sub is rendered useless? Does it mean the receiver sends EVERYTHING below 80Hz to the Subwoofer no matter what?"
    Patrick, It means if you select the "small" setting, the receiver sends anything 80hz and lower to the LFE. If you select "large" all frequencies will go to the mains.
    Jeremy
     
  4. Chip E

    Chip E Screenwriter

    Joined:
    Nov 25, 2000
    Messages:
    1,165
    Likes Received:
    0
    Trophy Points:
    0
    "I have noticed that a small minority of recievers have adjustible crossovers (sony, outlaw)"
    Don't forget B&K.... totally adjustable...neat to play around with too!
    - Chip
     
  5. Adam Kmiec

    Adam Kmiec Auditioning

    Joined:
    May 7, 2001
    Messages:
    9
    Likes Received:
    0
    Trophy Points:
    0
    Confusing bass redirection with x-over. The LFE track is designed for 120hz and below and when you set a speaker to small you are telling the receiver to REDIRECT any frequencies 80hz and below that would have been going to that speaker to the sub. Thus the sub would be responsible for handling the LFE track as well as all the redirected base from the speakers that are set to small. This is why a good sub is essential.
    ------------------
    Hunny time to sell the kids I need to upgrade.
     
  6. Patrick Larkin

    Patrick Larkin Screenwriter

    Joined:
    May 8, 2001
    Messages:
    1,759
    Likes Received:
    0
    Trophy Points:
    0
    So, if my Denon receiver sends everything 80Hz and lower to the sub (since my speakers are set to small), then what is the proper crossover setting for the sub? Or is the crossover setting on the sub ignored by the receiver?
     
  7. John Kotches

    John Kotches Cinematographer

    Joined:
    Mar 14, 2000
    Messages:
    2,635
    Likes Received:
    0
    Trophy Points:
    0
    If the subwoofer has an unfiltered input, that's the correct one to use.
    Otherwise, you want to turn the dial for the crossover all the way up to the highest frequency possible.
    Otherwise you get into what's called cascading crossovers, where the receiver and the subwoofer crossovers start interacting in strange ways.
    Regards,
     
  8. JohanK

    JohanK Second Unit

    Joined:
    Jan 22, 2000
    Messages:
    478
    Likes Received:
    0
    Trophy Points:
    0
    I think that this may be a holdover from THX which wanted the 80 Hz crossover point. From my experience, the 80 Hz works in a lot of systems with decent size bookshelf speakers and smaller floorstanders (-3 dB @ ~ 45 - 50 Hz).
    I'm still unclear as to whether the processor enacts the 80 Hz x-over on the LFE channel but I guess this is probably processor dependent. Anybody know?
    ------------------
    " Resistance is FUTILE! " -- The ( HOME THEATER ) BORG
    equipment list
     
  9. Burke Strickland

    Burke Strickland Second Unit

    Joined:
    Jul 31, 1997
    Messages:
    271
    Likes Received:
    0
    Trophy Points:
    0
    Aside from whatever ideological/design-principal backup a particular crossover point has, I'd be willing to bet that a "fixed" crossover is cheaper to implement than a variable one (that doesn't audibly degrade signal quality).
    Burke
     
  10. Kieran Coghlan

    Kieran Coghlan Second Unit

    Joined:
    Oct 26, 1998
    Messages:
    262
    Likes Received:
    0
    Trophy Points:
    0
    Adam K.--
    Not really. A crossover circuit is used to redirect the bass. A crossover circuit is basically a combination of a low-pass filter and a high-pass filter. Incidentally, folks, a common misnomer is to refer to the low-pass filter in the subwoofer as a "crossover". The term "crossover" should be used only to refer to a hpf/lpf combo, where the signal "crosses over" from one driver to another.
    Personally, the lack of adjustible crossovers in mass market receivers is a HUGE pet-peve of mine. Having an adjustible crossover, with settings down to about 50Hz at LEAST, should be the norm, not the exception, IMHO. Sony and Outlaw are the ONLY brands offering a reasonably priced receiver with adjustible crossovers. The B&K is a little pricey, but does have a fabulous bass management system.
    As for the REASON why manufacturers choose fixed crossovers, well, it's primarily because of price. But, the fact that THX said it was "okay" (in fact "preferable" even) doesn't make it any easier to convince manufacturers otherwise.
    Having only two choices when setting up your speakers (small or large) often results in people choosing the WRONG setting (i.e. LARGE), as almost ALL speakers on the market should be set up as "small" if you REALLY want to hear the FULL frequency range that DD and DTS offer.
    http://www.geocities.com/kierancoghlan/SPEAKERS1.html
    ------------------
    -Kieran
    My HT Page
     
  11. Phil Iturralde

    Phil Iturralde Screenwriter

    Joined:
    Oct 7, 1998
    Messages:
    1,867
    Likes Received:
    0
    Trophy Points:
    0
    Kieran - just wanted to say your "Home Theater Speaker Selection A Primer" article is excellent.
    I've always believed that manufacturing a typical 'subwoofer + satellite speaker' with "a flat response, if the flat part of the plateau is within +/- 3 dB of a perfectly flat line" (quotes from your article), was a difficult objective in real world enviroments.
    Check out my webpage http://www.geocities.com/p_iturra/Misc_HT_Speakers.html
     
  12. David Barteaux

    David Barteaux Stunt Coordinator

    Joined:
    Jan 6, 2001
    Messages:
    179
    Likes Received:
    0
    Trophy Points:
    0
    Am I correct in the following for the Denon 3801?
    Speakers = Small:
    All frequency below 80HZ from each channel is sent to the sub. LFE track is also sent to the sub.
    Speakers = Large:
    When sub mode is set to LFE, all frequency below 80HZ is sent to main speakers only and LFE track is sent to sub.
    When sub mode is set to LFE+MAIN, all frequency below 80HZ is sent to main speakers and sub, and LFE track is sent to sub.
     
  13. Kieran Coghlan

    Kieran Coghlan Second Unit

    Joined:
    Oct 26, 1998
    Messages:
    262
    Likes Received:
    0
    Trophy Points:
    0
    Phil,
    Thanks for the complement. I agree that manufacturing (let alone designing) a speaker like that is pretty much impossible in the real world. Keep in mind that my primer was intended for friends who, while they may be somewhat technically minded, don't know much about HT or audio at all. So, I had to pick and choose what I wanted to go into detail on, and what I would skip over, or simplify.
    I can't get your page to load right now, but I'll check it out when I get a chance.
    David:
    You are correct on your definitions of those two settings. However, I sort of cringe when people say "all frequencies below 80 Hz get sent to ...." etc. The term "all frequencies" is misleading. There is what's called a drop-off slope associated with any filter or crossover. So, If the low pass filter is defined at 80 Hz, then the signal sent to the "small" speakers is -3dB down from reference at 80 Hz, and then, depending on the slope of the filter, it drops off steadily after that. So, if the slope is say, -12dB per octave, then at 80Hz, it is -3dB, and at 40Hz, it would be -15dB. So, you can't really say that ALL frequencies are being sent to the sub, because there is a 40Hz signal being sent to the small speakers; it's just -15dB down from reference. [​IMG]
    HOpe that makes sense,
    -Kieran.
    ------------------
    -Kieran
    My HT Page
     
  14. Ranga

    Ranga Stunt Coordinator

    Joined:
    Nov 30, 2000
    Messages:
    107
    Likes Received:
    0
    Trophy Points:
    0
    David
    Are you sure that a sub mode of LFE+MAIN will send the bass to both the mains and sub?
    My DVD player (with built-in decoder) has only two settings - LFE and MIXED.
    So, if I set all my speakers to SMALL, sub mode will be set to MIXED (which should be the same as LFE+MAINS). In this case, I would assume that bass
     
  15. Jack Gilvey

    Jack Gilvey Producer

    Joined:
    Mar 13, 1999
    Messages:
    4,948
    Likes Received:
    0
    Trophy Points:
    0
    Keirnan,
     
  16. Shane Martin

    Shane Martin Producer

    Joined:
    Sep 26, 1999
    Messages:
    6,017
    Likes Received:
    0
    Trophy Points:
    0
    While some companies are starting to offer the Adjustable crossover the biggest problem is that they are not adjustable per channel like Sony. Outlaw's adjustment is a global setting as is Denon's new setting which is ok If you have the same speakers all around but if you use Tower mains that are suited for a lower crossover(40 or 60) then a global setting of 60 would probably be too high for bookshelf rears thus the NON-global Adjustable crossover becomes valuable.
    Also if Manufacturers are watching this I would prefer they allow the crossover to be adjustable in 10hz increments instead of the 20hz that Denon is trying(although with little effort).
    Under $2k the only 2 pieces of equipment capable of a fully adjustable crossover per channel are The Sony Line of Products.
     

Share This Page