Auto EQ speakers

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This topic contains 6 replies, has 5 voices, and was last updated by Profile photo of GaryW GaryW 4 years, 5 months ago.

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  • #58914
    Profile photo of DanZ
    DanZ
    Participant

    A great feature would be that the QU-PAC send a very fast signal from 20-20khz in a output, and analyse in the same time one microphone channel.

    Then auto adjust the GEQ to make the speaker more linear

    Actually, it is very hard to do this with the pink noise

    #58917
    Profile photo of Andreas
    Andreas
    Moderator

    The GEQ is much too coarse for such a purpose, and using a single mic for analysis can only give a rough hint, particularly in “complicated” rooms with several peaks and valleys in frequency response.

    #58919
    Profile photo of DanZ
    DanZ
    Participant

    For sure, we will not precisely tune studio monitors with that, but I want something to be able to correct a bit the speakers like I am doing actually with the RTA and pink noise generator, with good results, but more automated, as now it takes a lot of time and makes noise
    🙂

    Maybe will try to do a windows program for that if A&H can’t do it

    #58925
    Profile photo of cornelius78
    cornelius78
    Participant

    Analyzing a short burst might help flatten the speakers, but unless there’s a longer analysis there won’t be time to analyze room acoustics. IME these days newer speakers (especially active ones) are reasonably flat, it’s more the room issues you have to watch out for, as as Andreas pointed out, the response measured will change around the room. Also (and unless you’re using a decent array,) most point-source systems don’t have a very wide field of HF coverage. If you measure in the wrong spot, the auto-eq algorithm could decide to add +15dB to the top end, and that could be bad for the tweeters and bad for people who are actually in the tweeters’ coverage. Also, if it did do a long analysis and found hole at 100Hz, how would the system know if that hole is there because of speakers’ frequency response curve, and therefore it should boost, or if that hole is there because of a room cancellation issue, and so boosting +15dB @100Hz won’t do anything, in fact it could damage the speaker? It could also be there because of an XO issue. A lot of the subs I’ve seen, even something as big as dual 18s, generally only have decent frequency response down to 30-35Hz. If you’re analyzing 20Hz-20kHz and your algorithm decides there’s not enough 20-35Hz it’ll boost that range, which the subs aren’t designed for. At best it’ll mean no change, because the subs will be protected from such freqs, but if there’s no protection (no speaker management, amps with no DSP, passive subs) you could end up distorting the low end, or even breaking something.

    And peq in stead of geq all the way. Sweepable and adjustable Q: makes so much more sense than a geq (scalpel vs hatchet.)

    #58926
    Profile photo of Andreas
    Andreas
    Moderator

    And don’t forget to start over, once the audience filled the room. This not only changes resonant behaviour (may also automatically eliminate problematic spots) but may demand more power on the low end.

    #58930
    Profile photo of Chris93
    Chris93
    Participant

    You would need time-windowing of the received signal for this to work properly. It isn’t trivial.

    Chris

    #58986
    Profile photo of GaryW
    GaryW
    Participant

    If you wanted to do a quick sanity check, route pink noise thru a monitor (at low-ish volumes!) and use a good RTA app on your phone.

    On the Qu-Pad app, Setup->Audio->SigGen, then Pink Noise and select output channel.

    For more detailed analysis, I have this: http://supermegaultragroovy.com/products/fuzzmeasure/
    Of course, SMAART at the high end and the free REW would also give you similar results.

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