Does the PEQ have crossover filters?

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This topic contains 11 replies, has 5 voices, and was last updated by Profile photo of Mandel Mandel 1 month, 2 weeks ago.

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  • #115747
    Profile photo of paytoplay
    paytoplay
    Participant

    I’m interested in a CQ mixer. I’m seeing that there are delays available on the outputs for speaker alignment, but I’m not seeing any crossover filters available for the outputs. Does the PEQ have 24dB/octave high-pass and low-pass filters available? Crossover filters is an essential feature that seems to continuously be absent on many digital mixers for some reason.

    #115749
    Profile photo of paytoplay
    paytoplay
    Participant

    Secondary questions. Is Q/slope available for the high-pass and low-pass filters? If so, what is the Q range?

    #115753
    Profile photo of Lee7
    Lee7
    Participant

    Read the manual, you’d be surprised how much information you will glean from spending 10 mins. 😉

    #115763
    Profile photo of paytoplay
    paytoplay
    Participant

    Nothing in the manual that I saw specifying anything about high-pass and low-pass filters, whether they have slopes available, or the filter slope range. If I hadn’t already looked in the manual I wouldn’t have asked the questions. So I wasn’t surprised at anything. Maybe someone who actually knows something about this can say something about it.

    #115771
    Profile photo of KeithJ A&H
    KeithJ A&H
    Moderator

    Hi @paytoplay

    The closest thing would be the option for using LF and HF bands in the output PEQ as HP and LP Filters respectively.
    https://www.allen-heath.com/media/CQ_User_Guide_V1_1_0_iss1.pdf#page=89&zoom=auto,-361,555
    Note that these are 12dB/ocatave filters though.

    For speaker processing, it’s best to use a dedicated speaker processing unit, not a mixer.
    I understand you may be thinking ‘well if it’s just digital audio processing, why not just include speaker processing options too?’ – but the reason we don’t is that you’d end up with something that doesn’t do either task (mixing/system processing) as well as it could/should.

    Thanks,
    Keith.

    #115775
    Profile photo of paytoplay
    paytoplay
    Participant

    For speaker processing, it’s best to use a dedicated speaker processing unit, not a mixer.
    I understand you may be thinking ‘well if it’s just digital audio processing, why not just include speaker processing options too?’ – but the reason we don’t is that you’d end up with something that doesn’t do either task (mixing/system processing) as well as it could/should.

    Could you expand on that a bit? Surely I’m missing something. I’m thinking that an adequate filter is a adequate filter and that it would be very handy to have that capability inside the mixer rather than the extra weight and cost of a speaker processor. Thanks.

    #115778
    Profile photo of robbocurry
    robbocurry
    Participant

    I can see why you want it and why it may be a handy feature at a push.
    I saw this only once before IRL with an iLive system which had lots of spare output busses and processing.
    For a mixer to become a system processor you’re using up resources originally intended for it’s primary use as a mixer.
    Two way stereo crossover would take up four of six aux sends.
    Three way? Six of six auxes.
    Yes perhaps you could change the digital filters to 24db / octave but then add all different filter types, Butterworth, Linkwitz Reilly etc etc.
    All using up a finite amount of resources – plus many more parameters to consider that a mixer probably won’t target or do as well as a dedicated unit.

    I asked Keith why the CQ12 had only 2fx engines rather than the four of the CQ18 and CQ20 – the answer – processing power!

    Also consider this is a mixer that’s aimed at (relatively) new users with its easy setup parameters, you’re adding an unnecessary level of complexity that may cause more harm than good.

    Demand for this feature obviously not that great or it would be on every new digital mixer.

    From a longstanding viewpoint and redundancy, I’d far rather have a dedicated processor for a specific job where possible. 👍🏻😃

    #115779
    Profile photo of KeithJ A&H
    KeithJ A&H
    Moderator

    @paytoplay

    Sure! Using the filters as an example:
    A steeper filter requires more cycles and therefore more processing.
    Crossovers require splitting the signal and multiple filters which is also more processing.
    So instead of using (unfortunately finite!) processing power on filters which would not be useful to all users, we use the power for other more mixer-like things, like having more channels with separate processing on each, routing and summing etc…
    Adding the extra processing power to do it all in one unit would of course add cost, perhaps not as much another whole unit, but it would mean the product then cost more for everyone, not only those who want the system processing.

    Aside from the amount of processing available, a system processor is generally seen to belong to the system/venue. The majority of our mixers are used with different systems in different venues, so rather than having to adjust all the outputs at every show, you would tend to send a ‘flat’ (not quite the right word… ‘full’ perhaps?) mix to the house, and the system processor will then deal with the amps/speakers/room.
    When taking out smaller complete speaker systems, the most popular of these are active and generally include DSP tailored to the speaker.

    Hope this explains the approach a little better.
    Thanks,
    Keith.

    #115789
    Profile photo of paytoplay
    paytoplay
    Participant

    @robocurry @KeithJ A&H Thanks. Much appreciate the insight and helpful answers.

    #117294
    Profile photo of Mandel
    Mandel
    Participant

    @KeithJ A&H Thanks. I’m also trying to set a 24 db/oct crossover. So which filter type is 12 db? There are 3 types of filters on the LF and HF, top, middle and bottom (sorry, I dont know their names), Is the top or the bottom, 12 db?

    #117428
    Profile photo of KeithJ A&H
    KeithJ A&H
    Moderator

    @mandel

    The type options for LF and HF from top to bottom are:
    Shelf – cut or boost everything below/above the frequency
    Bell – cut or boost at the frequency, with variable width
    Filter – cut at 12dB per octave below/above the frequency

    Hope this helps!
    Keith.

    #118428
    Profile photo of Mandel
    Mandel
    Participant

    Thanks for being so helpful!

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