Trying to understand CX2310 subwoofer crossover frequency and signal flow

  1. #1 by Jon Goad on 02-01-2018
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    Trying to understand CX2310 subwoofer crossover frequency and signal flow

    Hello,

    I recently purchased a Behringer CX2310 Crossover to use with a pair of active subwoofers (EV EKX-15SP's) and active top PA speakers (RCF HD-12A's). My question is regarding the "XOVER FREQ" knob under the "Subwoofer" section (near the center on the front of the unit). The manual states the following:

    "This control governs the crossover frequency between the low signal and the subwoofer signal (10 to 235 Hz)."

    However, from numerous posts I've read, the Subwoofer "Xover Freq" is really just a low-pass filter for the mono-summed Subwoofer output. My question is this: is the signal at the Subwoofer output also affected by the "Low/High Xover Freq" control, or is it independent of it? In other words, does the Subwoofer out:
    1. Take the full-range signal at the stereo inputs, mono-sum them, then apply the low-pass filter (determined by the Subwoofer Xover Freq control), or...
    2. Take the full-range signal at the stereo inputs, apply the low-pass filter (determined by the Low/High Xover Freq contro), mono-sum that signal, then apply the low-pass filter controlled by the Subwoofer Xover Freq?

    I'm just trying to understand the internal signal flow/routing for this device so I can best determine how to connect things up with my speakers.

    Thanks,

    Jon

    Last edited by Jon Goad; 02-01-2018 at 12:06 PM.
  2. #2 by Michael Lapke on 02-02-2018
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    Hey Jon,

    Perhaps I can shed some light on this for you. The single XLR Subwoofer Output (SUBW OUT) jack on the back center of the CX2310 takes a summed mono signal from the input(s) and then uses the dedicated Subwoofer XOVER FREQ knob (found on the front center SUBWOOFER section) to control the which frequencies to pass to the XLR SUBW OUT jack.

    The CX2310 also has two additional XOVER Frequency knobs on the front of the unit, flanking to the left and right sides of the "Subwoofer" section, which are dedicated to handle frequencies of the XLR "LOW OUTS". Those two XOVER knobs, located below the LOW/MID - LOW/HIGH section on the front of the unit, only affect the XLR LOW OUTS on the back. They have no bearing on the XLR SUBW OUT whatsoever.

    Hope this helps clarify things, please let us know how everything goes with your setup.

    Michael Lapke
    Specialist, Community
    MUSIC Tribe
    BEHRINGER
  3. #3 by Jon Goad on 02-02-2018
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    Thanks Michael, that's what I wanted to find out!

    Jon
  4. #4 by Jon Goad on 02-05-2018
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    - Michael Lapke wrote View Post

    Those two XOVER knobs, located below the LOW/MID - LOW/HIGH section on the front of the unit, only affect the XLR LOW OUTS on the back. They have no bearing on the XLR SUBW OUT whatsoever.
    Unfortunately, based on my testing with the CX2310 this weekend, that statement appears to be incorrect. It appears as if the Subwoofer Out actually gets its signal from the mono-summed "Low Outs"--not directly from the inputs, and therefore the Low/High Xover Freq also affects the Subwoofer out, and the Subwoofer Xover Freq simply applies an additional low-pass filter to the output signal for the Subwoofer Out XLR jack. This seems like a strange way to design this feature, but it seems consistent with what I've read on some other forums.
  5. #5 by Michael Lapke on 02-06-2018
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    - Jon Goad wrote View Post
    Unfortunately, based on my testing with the CX2310 this weekend, that statement appears to be incorrect. It appears as if the Subwoofer Out actually gets its signal from the mono-summed "Low Outs"--not directly from the inputs, and therefore the Low/High Xover Freq also affects the Subwoofer out, and the Subwoofer Xover Freq simply applies an additional low-pass filter to the output signal for the Subwoofer Out XLR jack. This seems like a strange way to design this feature, but it seems consistent with what I've read on some other forums.
    Hi Jon,

    I could have sworn what I wrote was correct, but you very well might be right.

    When I typed that answer out to you I was only able to use the CX2310 manual as reference because I actually don't have a CX2310 to test with here in our office. I do apologize for that.

    I will follow up with my co-workers and confirm the correct answer for everyone here in the forum. Thanks you for being so patient and again sorry for the confusion.

    Michael Lapke
    Specialist, Community
    MUSIC Tribe
    BEHRINGER
  6. #6 by Jon Goad on 02-07-2018
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    Hi Michael,

    No problem. I should still be able to use the unit, but I'll just probably set the Subwoofer Xover Freq to the maximum setting and let the Low/High Xover Freq control the crossover point, even for the Subwoofer Out. The manual definitely needs some work to clarify how these features work. It's confusing, at best. One might expect that the Subwoofer Xover Freq would also control the crossover frequency between the Subwoofer Out and the Low Out, but it does not. It just applies the additional low-pass filter. I can only guess the intended application is if someone were bi-amping their 2-way top cabinets plus using Subwoofers, they could use the Low/High Xover to control the separation of frequencies for those bi-amped tops, and then they could use the Subwoofer Xover to low-pass only the extreme low frequencies that they would want to send to their subs.

    Thanks,

    Jon
  7. #7 by Michael Lapke on 02-07-2018
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    So I've now double checked on this and can confirm that what you've stated is indeed correct.

    For 2-Way Stereo operation, each of the CX2310's input signals hits the LOW / HIGH XOVER knob which splits the signal into two bands (Highs and Lows) using the selected value to determine which frequencies pass to the HIGH output and which ones pass to the LOW output. Then the SUBW XOVER knob allows you to dial in which frequencies from the selected LOWS that you want to pass specifically to the subwoofer XLR output.

    Again my apologies for the initial confusion. Hopefully this discussion helps others who might be confused similarly about the operation of this crossover.

    Michael Lapke
    Specialist, Community
    MUSIC Tribe
    BEHRINGER
  8. #8 by Jon Goad on 02-13-2018
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    Hi Michael,

    Thanks for the reply and confirmation. Since there's no way to disable the low-pass filter built into the DSP controls for my EV subs, I think my best bet for connecting things up in this case is to do something like this:
    1. Connect the L/R Main Outputs of my XR18 to the EV Subs' Inputs.
    2. Connect the Thru Outputs of the EV Subs to the CX2310. The Thru Outs pass the full-range signal, and do not apply a high pass filter.
    3. Connect the High Outputs of the CX2310 to the RCF HD12-A's. The Low Outs and Subwoofer Out will not be used.
    By doing this, I'll just be using the CX2310 as a high-pass filter for the top cabinets. This will keep me from stacking multiple low-pass filters in the chain for the subs, which I'm concerned could cause some phase shift or other weirdness.

    Jon
  9. #9 by Peter John on 04-03-2018
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    Hi...i am a new user here. As per my knowledge the CX2310 also has two additional XOVER Frequency knobs on the front of the unit, flanking to the left and right sides of the subwoofer section, which are dedicated to handle frequencies of the XLR low outputs.

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    Last edited by Peter John; 04-26-2018 at 09:27 AM.
  10. #10 by Jon Goad on 04-03-2018
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    Yes, that's correct. The question was about whether the Subwoofer Out was fed by the mono-summed output of the inputs, or the mono-summed output of the Low Freq outputs. What I discovered is that the Subwoofer Out is fed by the mono-summed Low Freq outputs, and then you can apply an additional low-pass using the Subwoofer Freq control.