Bypass fixed x-over

Discussion in 'AV Receivers' started by RyanJE, Jan 29, 2005.

  1. RyanJE

    RyanJE Second Unit

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    Anyone know how to bypass a fixed X-over in a receiver? My sub has a highpass set at 100hz. Can I-Should I parallel?
     
  2. RyanJE

    RyanJE Second Unit

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    bump.. Anyone!!

    I have tower speakers and hate to waste their capabilities.
     
  3. RyanJE

    RyanJE Second Unit

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    Yall scared??
     
  4. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    If your receiver lets you set the mains to "large", then that will bypass the receiver's crossover.
     
  5. John S

    John S Producer

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    Hmm, confusing post a little...

    You state you sub has xover at 100hz, you state your avr has a fixed xover setting.

    Then you ask about parallel like you are using the speaker connections to your sub.

    Before attempting the parallel thing, I would make sure it is cool on your sub to not have speakers connected to it, but using the speaker connection to it. If that makes sense. If so, this should be ok to do. Connection like that you AVR should be set, that there is no sub in the system at all, that way all sub bass and LFE should come out the speakers.
     
  6. RyanJE

    RyanJE Second Unit

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    Jon,
    I currently have my sub hooked up via LFE out from the receiver. It has a fixed filter at 100 hz. There are no speaker level outputs on my receiver just the single cable out im using. There are no speaker outs on my sub either. I want to cross my sub over around 60-70 hz but I cant when using the LFE out because its fixed at 100hz. So are there any potential problems with parallel. Will it break anything?

    Brian
    How will that work? Will my sub still play everything below 100hz along with my towers? I was under the impression that if I use the sub out on my receiver it sends everything below 100hz to my sub. If I do what your saying, will the receiver send LFE to the mains down to 60hz and then below 60hz to my sub..assuming I x-over my sub at 60hz?
     
  7. John Garcia

    John Garcia Executive Producer

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    With your mains set to SMALL, your sub is fed everything below 100Hz.

    With your mains set to LARGE, your sub will be fed LFE + bass below 100hz from any other speakers set to small. (LFE and BASS are not the same thing)

    By speaker level outs, John S means the MAIN speaker level outputs, which would feed your sub a full range signal and would allow you to use your sub's x-over. Then, you have to either run your mains full range off the main speaker outs or run them in-line with the sub. Running them in-line with the sub will defeat the goal you are trying to achive however, because they will again be filtered by the sub, most likely at a fixed point of 80-120Hz (most sub's speaker level outs are not variable). You will get the desired lower x-over, but the signal will not be as good as using it the way you have it hooked up already. Just set your mains to large and leave it the way you have it.

    If your mains aren't good to about 35Hz, then using a 60hz x-over may not be a good thing.
     
  8. RyanJE

    RyanJE Second Unit

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    My mains are good to 42hz and are currently set to small. Your saying set them to large. Also, I have no speaker level out on my avr. I only have the sub cable output. If I set them to large will my receivers fixed x-over be negated?? If so, I could then set my sub to 70hz.

    I understand that LFE is an extension of bass usually 10dbs louder since we are not as sensitive to low frequencies. For the record Im concerned with movies not music. I don't listen to music on my system much.

    Also I said my sub has a fixed high pass filter of 100hz. This differs from a cross over. Which doesnt matter anyway because my sub has no speaker level outs.
     
  9. John S

    John S Producer

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    Your sub has no speaker level in's and out's????
    Make and model please?

    If you set your fronts to large, the only thing that will come out of the sub is the lfe information. Some AVR's have the option for fronts and sub "both" for bass and LFE. LFE usually only has particular low end sound effects.

    Can you describe what you meant as running parallel in your first post???

    I just assumed you meant, L/R speaker outs to your speaker with a parllel connection to the sub speaker inputs, not going from your subs speaker outputs to the speaker if that makes sense.
     
  10. John Garcia

    John Garcia Executive Producer

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    If your speakers are driven by your receiver, these ARE your speaker level outputs - that would be used for "parallel" hookup you are talking about.

    If your sub has no speaker level outs, then setting your mains to small and lowering your sub's x-over will result in a dip or gap about the midpoint between the receiver's x-over and your sub's x-over. If you run your mains as large in parallel, you will get double bass, with the sub and mains reproducing the same information at the same time, and this is not always a good thing because you may get cancellation of standing waves at certain frequencies, depending on your room and speaker locations.

    LFE is a separate track and is present basically only on movies. I'm not sure if the .1 track for multichannel DVD-A/SACD/DTS CDs is considered true LFE or not, but it is a separate channel. The only way to completely turn off the receiver's x-over is to set all speakers to large. With your mains only set to large, the bass from any other speakers set to small will still be redirected to the sub at the fixed x-over.

    A response of 42Hz and a 100Hz x-over should work fine with your mains set to small, though an 80Hz x-over would probably work better. Your speakers will still potentially be recieving sound to about 50Hz, as a x-over is not an all-or-nothing sort of thing. I've used both 80 and 100, and I have to say it isn't a HUGE difference, but I prefer 80hz. I'd try it with them set to large and small and see which way sounds better to you.

    Is there something with your setup that you don't like that prompted the question? Have you calibrated with an SPL meter and test tones?
     
  11. RyanJE

    RyanJE Second Unit

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    Right, I meant no speaker level outs for a sub.. sorry. And my sub has speaker level in but not out. I have calibrated with an spl meter. What I dont like is that I have tower speakers that I set to small when they are bass capable. Also frequencies above 70-80 hz are localized and im trying to avoid that, as it is noticeable in my room.



    This is what I want but cant seem to achieve because my avr's x-over is fixed at 100hz. How exactly can I do this??

    P.S. My sub is a JBL E250p.
     
  12. RyanJE

    RyanJE Second Unit

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    Jon S

    That is what I meant by parallel. I thought by doing this the LFE would be sent to my mains and my sub, allow me to set my sub x-over to 70-80 and then utilize both (sub & towers) as LFE and bass. This seems as though it would give me a proper "marriage" between the two. Since you guys now know my specs should my towers be set to large or small. Either way am I screwed with a fixed x-over at 100hz??
     
  13. John Garcia

    John Garcia Executive Producer

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    If your room is the problem, which is what it sounds like, you are not going to fix it by lowering your x-over. Do you have a few locations that you can experiment with for your sub? Having bass come from both sub and mains set to large is likely to make the problem worse, not better, but this is going to depend on your room.

    Try setting your mains to large and lowering the sub's x-over point slightly, to see if that helps.
     
  14. RyanJE

    RyanJE Second Unit

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    If my mains are set to large does it bypass the avr cross over. If not, I dont want to double filter the my sub.
     
  15. John Garcia

    John Garcia Executive Producer

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    This was answered 3 or 4 times.

    With your mains set to SMALL you are cascading filters unless you can bypass the sub's internal x-over. If you cannot bypass the internal x-over, then you would set the sub's x-over to it's highest point. By adjusting the x-over down, you would be increasing the slope of the x-over, which may help in your particular case with the ~80Hz problem because it will roll off the higher frequencies faster. Adjust it down a few degrees at a time until you see if it helps or not.
     
  16. RyanJE

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  17. Brian Fellmeth

    Brian Fellmeth Supporting Actor

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    Your system has 2 separate crossovers- one in the receiver and one in the sub itself. The one in the sub is used when you feed it a full range signal. If you want to feed it from the LFE jack, then the crossover (or filter) in the sub should be disabled, which it seems that you can do by turning on that LFE switch. Now you have the choice of mains small or large. With mains small (and all other speakers small), The sub gets whatever is on the LFE track plus the deep bass from the other 5 channels, and conversely the other five channels have the deep bass removed. This reassignment of deep bass that occurs when the speakers are set to small from the 5 sats to the sub is not everything below 100 Hz, but a gradual transfer. The further below 100Hz you go, the higher percentage is sent to the sub.

    With the mains set to large,(center and surrounds left small) then the receiver's crossover is disabled for the main channels. They get whatever is laid onto the track and the sub sees none of it. The sub will only get the LFE track (if any) and deep bass from the center and surrounds.

    If your receiver was capable of crossing over at 80 or 60 Hz, then small is the way to go for many reasons. With a crossover as high as 100, then using small may result in localizable bass comming out the sub instead of the mains. Despite this issue with the small setting, its still probably a better choice. I know you are concerned with "wasting" the bass cabability of your mains. But just because they can do it dopesn't mean they should do it. It doesn't matter if the mains can croak out 45 Hz. What matters is can they can't do it as well as the sub can. If your sub is half decent, it will do 30-50Hz material far better than your "bass cabable" mains can. Let the specialist do its job. Further, your mains and your amps will perform better when unburdoned of deep bass which robs power and muddies midrange/mid bass.
     
  18. RyanJE

    RyanJE Second Unit

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    Wow, its so much clearer now. Thanks! I didnt really grasp the idea between bass and lfe. Ill just leave it as small then. I guess those articles I was reading were just confusing me more..
     

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