• 12-17-2003, 07:14 AM
    Willow
    where should the crossover be set
    If my mains- 50hz-27khz, center-55hz-27khz and my sub has 30hz-180hz ....where should the crossover be set by standard not with any SPL testing but by general rule of thumb...

    thanks
  • 12-17-2003, 09:49 AM
    piece-it pete
    Quote:

    Originally Posted by Willow
    If my mains- 50hz-27khz, center-55hz-27khz and my sub has 30hz-180hz ....where should the crossover be set by standard not with any SPL testing but by general rule of thumb...

    thanks

    After many many speakers I've found 80 hz to be a good starting point. I have also found that, in my situation, high passing the mains helps keep my room peaks in line. Your receiver may have this built in.

    Playing around with different settings for many days is probably a must (nothing is ever easy:).

    Pete
  • 12-17-2003, 10:29 AM
    topspeed
    Quote:

    Originally Posted by Willow
    If my mains- 50hz-27khz, center-55hz-27khz and my sub has 30hz-180hz ....where should the crossover be set by standard not with any SPL testing but by general rule of thumb...

    thanks

    First off, a SPL meter won't help you at all on this except to match volume levels. If you are running your mains full range, the safest thing to do would be to set your sub at 50hz. As Pete mentioned tho, you should play with it quite a bit to see where it compliments (as oppossed to overpowering) your mains. While your mains may be rated to 50hz, they may start rolling off quickly way before that. I'd start at 50 and then work my way up if necessary. Remember, the sound should be uniform.
  • 12-17-2003, 10:44 AM
    Willow
    Quote:

    Originally Posted by topspeed
    First off, a SPL meter won't help you at all on this except to match volume levels. If you are running your mains full range, the safest thing to do would be to set your sub at 50hz. As Pete mentioned tho, you should play with it quite a bit to see where it compliments (as oppossed to overpowering) your mains. While your mains may be rated to 50hz, they may start rolling off quickly way before that. I'd start at 50 and then work my way up if necessary. Remember, the sound should be uniform.

    I have my mains set at Normal (which is small I guess only 2 choices small or large) so maybe 50hz is not enough I will try 50 then work my way...

    Thanks
  • 12-17-2003, 01:40 PM
    Kursun
    Which crossover do you mean, the crossover of the receiver or the one on the subwoofer? Since the crossover frequency selection options on most receivers are few I'm in doubt. You should bypass the crossover on the subwoofer...
  • 12-17-2003, 01:47 PM
    Willow
    Quote:

    Originally Posted by Kursun
    Which crossover do you mean, the crossover of the receiver or the one on the subwoofer? Since the crossover frequency selection options on most receivers are few I'm in doubt. You should bypass the crossover on the subwoofer...

    Im talking about the xover on the sub....for some reason there is not one on my kenwood receiver all they have is "truebass levels" there is nothing on it to adjust those levels...so I dont even know if the sub out is filtered or not...i think its time to get a better receiver.
  • 12-17-2003, 02:29 PM
    Kursun
    The sub out on the Kenwood is probably filtered at a fixed frequency around 80-100 Hz. (Not a disastrous case, considering even the top flagship Yamahas have a fixed crossover frequency at 90 Hz. I don't know about their very latest models...).

    But if so, having a second crossover cascaded at the sub end may cause troubles (complication of adjustments and more important, too much phase shifts due to cascaded low-pass filters). You may try disabling the crossover on the sub, if not possible set it at its highest crossover frequency so that bass management is done only at the receiver end.
  • 12-17-2003, 02:37 PM
    Willow
    Quote:

    Originally Posted by Kursun
    The sub out on the Kenwood is probably filtered at a fixed frequency around 80-100 Hz. (Not a disastrous case, considering even the top flagship Yamahas have a fixed crossover frequency at 90 Hz. I don't know about their very latest models...).

    But if so, having a second crossover cascaded at the sub end may cause troubles (complication of adjustments and more important, too much phase shifts due to cascaded low-pass filters). You may try disabling the crossover on the sub, if not possible set it at its highest crossover frequency so that bass management is done only at the receiver end.

    thanks then the sub suggested if the receiver is filtered not to use the Y cable...Ill try that again tonight but have no clue what to set the sub a xover at....50 80 ... ??? or higher 100 Im not sure what that means I should do if the Kenny is set at around 80 my sub should pick up where this leaves off ??
  • 12-17-2003, 02:54 PM
    Kursun
    The crossover on the the sub is like an atrophied organ. A HT system doesn't need a crossover on the sub! A crossover on a subwoofer is more of a nuisance if it is not bypassable. Don't use the crossover on the sub. Either disable it or set it to its highest frequency so that it will have minimum effects. Otherwise it may degrade your sound.

    Crossovers on a sub were useful when there were no dedicated sub outs on amps (mostly 2 channel). They aren't useful anymore, and they shouldn't be used.
  • 12-17-2003, 02:56 PM
    Willow
    Quote:

    Originally Posted by Kursun
    The crossover on the the sub is like an atrophied organ. A HT system doesn't need a crossover on the sub! A crossover on a subwoofer is more of a nuisance if it is not bypassable. Don't use the crossover on the sub. Either disable it or set it to its highest frequency so that it will have minimum effects. Otherwise it may degrade your sound.

    Crossovers on a sub were useful when there were no dedicated sub outs on amps (mostly 2 channel). They aren't useful anymore, and they shouldn't be used.

    and up means clockwise or counterclockwise
  • 12-18-2003, 11:42 AM
    Willow
    withh all your replies and the sub manual and polk's HT handbook...I turned up the Xover all the way and it said to use the Y cable to Bypass the sub filtering..I'll see how this works

    Thanks
  • 12-18-2003, 12:19 PM
    kexodusc
    Hi guys, I'm trying to interpret this thread properly and apply it to my setup. Are you telling me that on my Yamaha, with my speakers set to "large" and my sub plug into the LFE output that I shouldn't set my subwoofer's cutoff to anything but the highest frequency (my sub doesn't have a switch to disable the cutoff option)?
    I don't understand how setting a cutoff on my sub to, say, 60 Hz, wouldn't just filter out whatever the receiver didn't, while keeping all the desired frequencies in tact? Can anyone clear this up for me? Thanks
  • 12-18-2003, 12:32 PM
    Willow
    Quote:

    Originally Posted by kexodusc
    Hi guys, I'm trying to interpret this thread properly and apply it to my setup. Are you telling me that on my Yamaha, with my speakers set to "large" and my sub plug into the LFE output that I shouldn't set my subwoofer's cutoff to anything but the highest frequency (my sub doesn't have a switch to disable the cutoff option)?
    I don't understand how setting a cutoff on my sub to, say, 60 Hz, wouldn't just filter out whatever the receiver didn't, while keeping all the desired frequencies in tact? Can anyone clear this up for me? Thanks

    in my case the kenny has a filter on the sub out and I dont want the filter in the sub as well....so I turn up the Xover on the sub all the way up and use the Ycable to bypass my sub's filter and let the receiver's filter do the work
  • 12-18-2003, 01:09 PM
    Kursun
    Quote:

    Originally Posted by kexodusc
    Hi guys, I'm trying to interpret this thread properly and apply it to my setup. Are you telling me that on my Yamaha, with my speakers set to "large" and my sub plug into the LFE output that I shouldn't set my subwoofer's cutoff to anything but the highest frequency (my sub doesn't have a switch to disable the cutoff option)?
    I don't understand how setting a cutoff on my sub to, say, 60 Hz, wouldn't just filter out whatever the receiver didn't, while keeping all the desired frequencies in tact? Can anyone clear this up for me? Thanks

    If your receiver is doing the bass management and sending the sub signals through what we call a low-pass filter (passes the low frequency bass and blocks high frequency treble) there is no reason for additional filtering (crossover) at the subwoofer end. If you do so you are over-doing a good thing.

    Though we have to use crossovers (low-pass, high-pass, band-pass filters), we must know that they do have negative side effects. Because of this some speaker manufacturers keep trying to design crossoverless speakers, or speakers with minimal crossovers.

    Crossovers, especially the high order crossovers produce severe phase shifts and group delay distortions. Group delay distortions are especially audible at bass frequencies. It's a highly complex electro-mechanical subject.

    A good reading piece:
    http://www.trueaudio.com/post_010.htm

    If you think that link is much too technical, think of a bass drum playing, listen to it, it has a tight sound. Then wet the bass drum and then play it, it now sounds as if something is wrong, boomy, soggy, thumpy... This may be an example of sound with high group delay.

    By using one crossover (on the subwoofer) after another (one on the receiver) you are cascading them, producing filtering of unnecessary magnitude. That introduces too much distortion. You've got to find a balace. Just use the crossover on the receiver and be happy. Don't over-do it.
  • 12-18-2003, 01:45 PM
    Willow
    just skimmed over that URL you put up some of it almost alien language . Is just me or is bass management one if not the most complicated set ups of a system ?
  • 12-18-2003, 01:48 PM
    Kursun
    On the other hand...
    Quote:

    Originally Posted by kexodusc
    Hi guys, I'm trying to interpret this thread properly and apply it to my setup. Are you telling me that on my Yamaha, with my speakers set to "large" and my sub plug into the LFE output that I shouldn't set my subwoofer's cutoff to anything but the highest frequency (my sub doesn't have a switch to disable the cutoff option)?
    I don't understand how setting a cutoff on my sub to, say, 60 Hz, wouldn't just filter out whatever the receiver didn't, while keeping all the desired frequencies in tact? Can anyone clear this up for me? Thanks

    If you don't experience any audible negative side effects on your particular setup, there is actually no reason why you shouldn't keep on using the subwoofer's crossover. It may be one way to fine tune the tonal balance of your system.

    In my particular setup I have chosen "small" speakers (though they are all actually huge), and the receiver crossover frequency set at 50 Hz. (No crossover active at the sub).

    In your case, if you select "small" there'll be a hole at 60-to-90 Hz. I think Yamaha's choice of fixed 90 Hz. crossover frequency to be extremely limiting for system fine tuning.
  • 12-18-2003, 01:54 PM
    Willow
    Quote:

    Originally Posted by Kursun
    If you don't experience any audible negative side effects on your particular setup, there is actually no reason why you shouldn't keep on using the subwoofer's crossover. It may be one way to fine tune the tonal balance of your system.

    In my particular setup I have chosen "small" speakers (though they are all actually huge), and the receiver crossover frequency set at 50 Hz. (No crossover active at the sub).

    In your case, if you select "small" there'll be a hole at 60-to-90 Hz. I think Yamaha's choice of fixed 90 Hz. crossover frequency to be extremely limiting for system fine tuning.

    so should we turn it up to say 180 or turn it down to 60
  • 12-18-2003, 02:02 PM
    Kursun
    Quote:

    Originally Posted by Willow
    just skimmed over that URL you put up some of it almost alien language . Is just me or is bass management one if not the most complicated set ups of a system ?

    Just enter the words PHASE+SHIFT+GROUP+DELAY on google.com and see the most alien technical language on the net. :D

    You are indeed absolutely correct that bass management is one of the most complicated subjects. "Standing waves" and room acoustics are probably other factors to be considered. Think of it, if you allow your main speakers to handle deep bass along with the sub, by selecting "large" speaker option, you may actually get less bass in some cases instead of more...
  • 12-18-2003, 02:31 PM
    Kursun
    Quote:

    Originally Posted by Willow
    so should we turn it up to say 180 or turn it down to 60

    I assume you mean the crossover frequency...
    It depends on the speakers option (small (normal for your case)/large you have selected.

    Ideally you should disable the crossover on the sub and select "small" speakers. This is the classic setup. Even better would be having a receiver which allows selecting the sub-out crossover frequency.

    Another option to try (if you insist on using the sub's crossover too):
    Select "large" speakers with sub crossover on and set at lowest (60). If the sound is thin and you want more, thicker (with more mid-bass) bass, try higher crossover frequency settings (70-80-90 Hz)

    Selection of "small" speakers and using the sub's crossover too is tricky, and should not be tried.
    Because
    If you select "large" speakers: the speakers will reproduce full range frequencies.
    If you select "small" speakers: the speakers will stop reproducing below the receiver's crossover frequency and all the remaining bass frequencies below will be expected to be reproduced by the subwoofer. But if you limit the frequencies the subwoofer will produce by utilizing the crossover on the sub there is the risk of some frequencies not being reproduced neither by the sub or the main speakers.
    As an example:
    Let's assume your receiver's crossover is fixed at 80 Hz. Since you have chosen "small" speakers, frequencies below 80 Hz will be filtered from the main speakers. No problem as the subwoofer will reproduce the frequencies below 80 Hz. But if you use and adjust the sub's crossover to 60 Hz. then the sub will be mute above this frequency. So in this case frequencies above 60 Hz and below 80 Hz won't be reproduced by either the sub or the main speakers. We don't want this.

    I hope all this is not foreign language... :)
  • 12-18-2003, 02:33 PM
    Willow
    Quote:

    Originally Posted by Kursun
    Just enter the words PHASE+SHIFT+GROUP+DELAY on google.com and see the most alien technical language on the net. :D

    You are indeed absolutely correct that bass management is one of the most complicated subjects. "Standing waves" and room acoustics are probably other factors to be considered. Think of it, if you allow your main speakers to handle deep bass along with the sub, by selecting "large" speaker option, you may actually get less bass in some cases instead of more...

    mine are set to small/normal...It was another replier who posted his were at large...Im glad my bass manag. days are almost over for this system..
  • 12-19-2003, 07:01 AM
    Willow
    Quote:

    Originally Posted by Kursun
    I assume you mean the crossover frequency...
    It depends on the speakers option (small (normal for your case)/large you have selected.

    Ideally you should disable the crossover on the sub and select "small" speakers. This is the classic setup. Even better would be having a receiver which allows selecting the sub-out crossover frequency.

    Another option to try (if you insist on using the sub's crossover too):
    Select "large" speakers with sub crossover on and set at lowest (60). If the sound is thin and you want more, thicker (with more mid-bass) bass, try higher crossover frequency settings (70-80-90 Hz)

    Selection of "small" speakers and using the sub's crossover too is tricky, and should not be tried.
    Because
    If you select "large" speakers: the speakers will reproduce full range frequencies.
    If you select "small" speakers: the speakers will stop reproducing below the receiver's crossover frequency and all the remaining bass frequencies below will be expected to be reproduced by the subwoofer. But if you limit the frequencies the subwoofer will produce by utilizing the crossover on the sub there is the risk of some frequencies not being reproduced neither by the sub or the main speakers.
    As an example:
    Let's assume your receiver's crossover is fixed at 80 Hz. Since you have chosen "small" speakers, frequencies below 80 Hz will be filtered from the main speakers. No problem as the subwoofer will reproduce the frequencies below 80 Hz. But if you use and adjust the sub's crossover to 60 Hz. then the sub will be mute above this frequency. So in this case frequencies above 60 Hz and below 80 Hz won't be reproduced by either the sub or the main speakers. We don't want this.

    I hope all this is not foreign language... :)

    so the sub should pick up where the receiver left off ???
  • 12-19-2003, 09:45 AM
    Kursun
    Quote:

    Originally Posted by Willow
    so the sub should pick up where the receiver left off ???

    Exactly!
  • 12-24-2003, 12:38 PM
    kgveteran13
    sub xover
    I'll take a little bit from all the posts.80hz is the easiest for these reasons.When you set the crossover at 80hz you only have one ch. to deal with when trouble shooting room modes.This will and should be done with a parametric due to the size of the peaks (usually above 10-15db each)If the mains have their own peaks they can be dealt with useing a third octave eq.Being out in the room where the mains should be usually helps in keeping their peaks to a minimum and smoothing the response.I'm not sure why THX adopted this method but it works for me.65hz lead to too many problems trouble shooting modes.