Receiver crossover ????

Discussion in 'AV Receivers' started by RyanJE, Jan 10, 2005.

  1. RyanJE

    RyanJE Second Unit

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    How do I know where my receivers Cross-over is set at. Is there an industry standard? It doesn't say in the manual. I ask because my sub has an LFE input and switch that deactivates its adjustable crossover. Im not sure if I want to do that or not, because my fronts are 8" towers and I would like those and the sub to produce bass. What do you guys think??
     
  2. JohnSmith

    JohnSmith Supporting Actor

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    What make & model is your av amp?
    In any case, you always want to bypass the subs own crossover if using bass managament elseware. You only need the subs own crossover if sending full-range.
     
  3. RyanJE

    RyanJE Second Unit

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    I have a sony str de-595. So its good to bypass the subs crossover. I just want my towers to play bass as well as my sub.
     
  4. JohnSmith

    JohnSmith Supporting Actor

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    You don't want the mains and sub to play duplicated bass frequencies, as that'll just cause a booming effet.

    You want the subwoofer to fill in under where the mains drop-off. So if your mains are around 40hz, then set mains to 40hz or higher, then subwoofer crossover on the av amp is set 40hz or higher (both to the same setting)

    Of course there's room gain to take into consideration..but 40/40, 80/80 settings usually work fine.
     
  5. RyanJE

    RyanJE Second Unit

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    Thank you much so far. But my amp wont let me set the crossover, its lower end. What should I do. Am i screwed with the internal crossover.? I was looking at this article, http://www.onhometheater.com/features/20040501.htm,
    My reciever only has a filtered sub output. At least I think its filtered. Its a single sub output.
     
  6. Jack Daniel

    Jack Daniel Auditioning

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    i don't even really know much about crossovers, but i also don't even know if my amp even has a subwoofer plug.
     
  7. John Garcia

    John Garcia Executive Producer

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    It's a fixed x-over, meaning it's on or off, since you do not have the ability to change it. It is in effect when you set any or all of your speakers to "small". I couldn't tell you what it is, but I'd guess it is either 100Hz or 120Hz.

    Very few receivers these days do not have a sub pre-out, even the lowest models, so I'm sure it has one unless it is an older unit.

    You wouldn't set your receiver and sub to the same x-over point, as they would combine together and create an extremely steep slope - you would set your sub's x-over to the highest point and let the receiver's x-over handle it.
     
  8. RyanJE

    RyanJE Second Unit

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    I think I don't have much of a choice. Unless I use the front channels to the sub and then the sub to the front speakers. I'd have to say I have no sub on the receiver. Do you think that would work??
     
  9. John Garcia

    John Garcia Executive Producer

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    That will work, but it won't buy you much, since the x-over in the sub is also fixed, and is also typically 100Hz or 120Hz.
     
  10. RyanJE

    RyanJE Second Unit

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    My subs x-over is adjustable from 50-150hz if i dont use the LFE setting.
     
  11. ScottCHI

    ScottCHI Screenwriter

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    that's probably just a low-pass filter. what sub do you have? if it's like most, the sub's "crossover" is really only a variable low-pass filter and a fixed high-pass filter, usually @ around 80-120Hz.

    what are you trying to accomplish, exactly? what are your front speakers? do you run any other speakers and what are they? even though you consider it low-end, your receiver's fixed crossover is probably OK for your speakers, if you do want to run them SMALL. you should disable or bypass your sub's "crossover", if you have that capability; if not, set the "crossover" as high as it will go.
     
  12. RyanJE

    RyanJE Second Unit

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    I Have two 8" towers rated down to 42 hz and then a center and two surrounds. The towers I want as large. My receiver only has an LFE output for the sub and the sub has a switch that bypasses its crossover when the LFE channel is used. If this is the case wouldnt my sub be playing below 100hz. Would my towers be also playing these frequencies or cut off at 100hz? Either way 100hz seems to high with bass capable speakers.
     
  13. ScottCHI

    ScottCHI Screenwriter

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    the receiver's crossover will only be applied to speakers that you run as SMALL, so it's a moot point as far as your front speakers are concerned if you're going to run them as LARGE, right?

    it seems you may need to do some reading-up on bass and LFE management.
     
  14. John Garcia

    John Garcia Executive Producer

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    Wouldn't that be a variable low pass and fixed high pass? I think we had this discussion before, and most subs tend to have a fixed high-pass. I don't think I've seen many, if any, active subs with a fixed low pass.

    What sub? Since you have the ability to bypass the x-over, that's what I would do. You can try your mains both ways and decide which way they sound better to you in your room. A x-over is not a all-or-nothing kind of thing, it has a slope that slowly diminishes output starting at the x-over frequency. If you have a 100Hz x-over, your mains will still be getting sound around 50Hz and possibly lower, at a reduced level as you move further from the x-over point. When your mains are set to large, the bass is not redirected to the sub, so it will not play from both, but they will overlap at some frequencies with bass from the other speakers.

    Here's where it gets trickier - with large mains and a receiver of this level, it is much more to your advantage to set your speakers to small because the sub will be able to handle bass much better than the receiver will with your mains. Low frequencies use more power, so your receiver will be working a lot harder by trying to reproduce those frequencies, leaving you less total available power for dynamic peaks.
     
  15. ScottCHI

    ScottCHI Screenwriter

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    DOH!

    yes. my mistake. i wrote that completely backwards. not what i meant to say! OY!

    i'm correcting it, now. thanks. :b
     
  16. RyanJE

    RyanJE Second Unit

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    This is cut from the other thread.. Tell me if this is right, I ahve read many articles on this and other sites, I may be missing something. Heres what I'm thinking,

    Well I have 8" tower speakers that are rated down to 42hz. I want them as large. Why wont the crossover come into to play? I want them to play bass as well. I want them to play the higher frequencies, i.e. above 70hz and I want the sub to play below the 70hz point. If the Crossover is fixed at 100hz on the LFE channel wouldnt that mean all signals below 100hz are sent to the sub? These frequencies are much to high and would create too much bump. So if there set to large they could play down to 42hz and as a result the sub would also be playin between 42hz and 100hz. Then the sub would be by itself below 42 hz. Resulting in a bump in the 42-100hz range.

    (P.S. I dont have this sub yet its coming on wed.)
     
  17. RyanJE

    RyanJE Second Unit

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    P.S. Sorry I didnt originally mean to run these 2 threads together.

    Am I Not going to be able to marry my sub with my mains because of my poopy receiver???
     
  18. ScottCHI

    ScottCHI Screenwriter

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    WHAT COMES OUT OF THE SUB?

    well, obviously LFE comes out of the sub.

    any low-frequency info below the receiver's crossover that would have normally been destined for speakers that are set to SMALL will come out of the sub.

    but, normally, low-frequency info meant for speakers set to LARGE is NOT duplicated in the sub.

    now, that said, many receivers WILL have a setting that will allow you to duplicate this bass info or create a sub channel from the front L+R info when the front speakers ARE set to LARGE. and YES, it usually utilizes the receiver's internal crossover setting. but it creates the unwanted bass redundancy you described either here or in that other thread.

    as john suggested, your best bet is to probably run your front speakers as SMALL. with a low end rated @ 42Hz, they are not full-range speakers. we still are only speculating as to what your receiver's crossover may be. if it's at or very close to 80Hz, it's actually ideal for your speakers with a SMALL setting. if it's 100Hz, it may be slightly high, but running the speakers as SMALL would still probably be your best option.

    edit: well, in looking at the manual for your receiver, it appears that it may, when there is no LFE material present in that channel already, default to creating a sub channel no matter whether your front speakers are set to LARGE or SMALL, when it's run in it's AFD AUTO mode. if that's truly the case, it's another good reason to run your front speakers as SMALL, as it would create the unwanted bass redundancy you mention when set to LARGE.
     
  19. RyanJE

    RyanJE Second Unit

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    Finally im seeing the light at the end. Im a newbie so this stuff is still somewhat confusing to me. Thank you all extremely much for helping me understand how these things work. [​IMG]

    In light of the latter responses I have on last question. Would it be beneficial, and safe, to run speaker wire from my front L & R outputs on my amp to the sub and then from the sub to the front speakers. Set the receiver to subwoofer "no" there by enabling the sub crossover and bypassing the LFE filter. I would then set the sub x-over to 60-70 hz to blend with my mains. Is this possible and safe??

    This method is explained here... http://www.onhometheater.com/features/20040501.htm
     
  20. ScottCHI

    ScottCHI Screenwriter

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    first, see my edit, above.

    it's absolutely possible, as described in the link you posted.

    but your front speakers will then be running, essentially, as SMALL, with the only thing gained being a variable low-pass filter. unless the sub passes a full-range signal through it's speaker-level connections (very few do), the speakers will still only receive info above the sub's fixed high-pass filter, which is probably at least as high as your receiver's. you might as well just use the receiver's crossover and set the speakers to SMALL.

    now, you can also just connect the speakers to the same outputs as the sub on the receiver, thereby feeding them a full-range signal. and yes, this is safe. but in telling your receiver that you have no sub, you'll be sending all the LFE to the mains as well as the sub in this instance. probably not desirable; most people don't want full LFE in both their mains and sub.

    why don't you get everything hooked up conventionally and give it a spin, first? disable the sub's crossover (or set it as high as possible). try both LARGE and SMALL for your front speakers. as i said in the edit above, from the looks of it, your receiver will produce a sub channel for you, either way, when there isn't LFE info present already.

    btw, HERE is a good link for you that has been on the polk audio site for a while regarding this same subject.
     

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