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Thread: Can't decide which sub cross-over,80 or 120Hz?

  1. #1
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    Can't decide which sub cross-over,80 or 120Hz?

    Hi:
    I have a RCF 902AS subwoofer and a pair of Yamaha DXR10 powered tops,but can't decide which x-over I prefer,80 or 120Hz.
    I am going from my pre-amp main-outs to my RCF sub and from there to my Yamaha tops,but not sure what I like better,crossing over to the tops from the sub at 80 or 120Hz...I can't decide what I like better...120Hz has more bass,but a little muddy,80Hz seems to put the sub to sleep,when there is no bass available (obviously it won't come on if there is no bass info present) in the track,but seems tighter,but not as much when it does come on...can't decided which xover setting to use...what would you use? ThanksH50
    Last edited by Huck50; 12-03-2022 at 10:44 AM.

  2. #2
    Whichever you need to so that the mains aren't strained. I use 80Hz in my home theater, as I can't play loud enough to tax the mains excursion limit in my living room. I use 100Hz for my PA, because it can play loud enough to stress the mains.
    Bill Fitzmaurice
    Bill Fitzmaurice Loudspeaker Design
    www.billfitzmaurice.info/forum

  3. #3
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    Quote Originally Posted by Bill Fitzmaurice View Post
    Whichever you need to so that the mains aren't strained. I use 80Hz in my home theater, as I can't play loud enough to tax the mains excursion limit in my living room. I use 100Hz for my PA, because it can play loud enough to stress the mains.
    Thanks,H50

  4. #4

  5. #5
    First off.. just checking.. you have the sub set to "xover" mode, right?

    On the 80Hz setting, the problem you have got is that the DXR10's response is great right down to 80Hz, BUT drops off pretty sharply below that. Keeping in mind that the crossover doesn't just chop right off at the frequency you've set, but more of a gentle slope where the tops and subs hand off to each other.. 80Hz is right in the middle of that handoff. That means that below 80Hz you are going to have a noticeable dip in bass response.. and that seems to be what you're hearing.

    If you had a regular DSP in your system you could easily fix this, but not much you can do with what you have got except turn up the sub gain a bit.. but you won't get smooth bass response with an 80Hz crossover setting.

    BUT, what you are hearing could also be partly due to phase issues, so what I suggest is to try the phase button on the sub in both positions (0 and 180) and see if one sounds better to you. Give it a good listen both ways and choose whichever seems the least bad.

    The other thing you can do is, on your tops, if D-Contour is off, try with it on. This gives you a bass boost right around 80Hz, it is not exactly the right eq you need but it may give you a better result than you are getting. Then adjust your sub level and try to get it to a good compromise. It won't solve the basic problem I described above, but it may smooth things over for ya.

    On the 120Hz setting, you have got a couple of different problems to deal with:

    First, that's the upper frequency response spec of the sub.. It is rated 45-120Hz +/- 3dB.. so again, in the area the top and the sub are handing off to each other, you'll have a dip.. in this case a dip around 120hz and above where the sub is starting to drop off faster than the top is taking over.

    Second, that the higher you cross over the more any phase/timing issues (as mentioned before) will be noticed. Again try the phase switch both ways. Also check the settings on the tops, if you have got D-Contour on, turn it off. You may also want to try moving your tops relative to the subs.. that is, move your tops closer to you or further away from you while leaving the sub where it is.. or move the sub and leave the tops. We're talking about moves of from a few inches up to around 2 feet. This is the same as adjusting delay if you had a DSP. You would be surprised what a big difference this can make. For that you probably will want a helper.. you can put the sub on a dolly and have the helper roll it toward and away.. you will hear it.... Once you know what spacing is optimal for your system just keep that in mind wherever you take it.

    But yea, end of the day, what is really best for this system is a 100Hz crossover frequency but unfortunately your sub does not have that setting, the solution is to get a separate DSP and use that for your crossover rather than the one in the sub.
    Last edited by light-o-matic; 12-09-2022 at 11:22 AM.

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