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Shelf EQ not possible?

Jonas_hJonas_h Posts: 2
in London Architect with Soundweb London
I have a London Soundweb 160 which and I have just received presets for my speakers. The presets require that I use a shelf EQ where I set frequency, gain and Q. To my surprise, I cannot seem to find this kind og filter on the BSS unit. Its possible to make a shelf but I cannot set the Q value.
The preset requires Freq=4,5khz, Gain -12db, Q=9.

Is it really true that this is not possible on the Soundwebs? The presets are for the Crown DSi/XTi amps which have this possibility and is way cheaper/simpler than the BSS units.

Comments

  • GrahamGraham Posts: 27
    It is part of the Parametric EQ. Set the filter type to high or low shelf.
  • Jonas_hJonas_h Posts: 2
    \Graham\ wrote:
    It is part of the Parametric EQ. Set the filter type to high or low shelf.
    No, it is not possible to set the Q value.

    Compare these results: (see picture below)

    One is the Crown DSi amp and the other is the Soundweb london. This will not result in the same speaker tuning.
  • Jonas_hJonas_h Posts: 2
    \Jonas_h\ wrote:
    \Graham\ wrote:
    It is part of the Parametric EQ. Set the filter type to high or low shelf.
    No, it is not possible to set the Q value.

    Compare these results: (see picture below)

    One is the Crown DSi amp and the other is the Soundweb london. This will not result in the same speaker tuning.

    Hmm anybody? :)
  • HARMAN_Jerome_KingHARMAN_Jerome_King Posts: 328
    Here is your picture
    bss_crown.jpg
  • HARMAN_Jerome_KingHARMAN_Jerome_King Posts: 328
    Could you double check that the values given by the speaker manufacturer is a SHELF with Q=9 ?
    There is no relation between Q and slope. Q does not apply to a Shelf EQ, despite what the Crown amp control panel displays.
  • Jonas_hJonas_h Posts: 2
    \Jerome King\ wrote:
    Could you double check that the values given by the speaker manufacturer is a SHELF with Q=9 ?
    There is no relation between Q and slope. Q does not apply to a Shelf EQ, despite what the Crown amp control panel displays.
    The presets for the speaker is a Crown DSi preset file, so they are created with those settigns I showed.

    But I am confused about the Q value of the shelf too. Maybe there is a way to make the same setting by using the standard shelf from the BSS in addition with a single bell-filter? I just dont know the conversion.
  • zetasj55zetasj55 Posts: 1
    One is the Crown DSi amp and the other is the Soundweb london. This will not result in the same speaker tuning.
  • Jonas_hJonas_h Posts: 2
    Yes, I know, but the presets has not been published for the BSS. But given that the BSS is a much more advanced and powerful device, I would assume that I can just look at the Crown DSi settings and input them on the BSS. But this is not allowed because of the missing shelf functionality.
  • HARMAN_Jerome_KingHARMAN_Jerome_King Posts: 328
    This is not missing functionality. There is no such thing as Q for a shelving filter. Q is a function of bandwidth of bell curves as you see in parametric filters. Bandwidth does not apply to a shelf.
    I think that best you can do is match the EQs up visually or by sending pink noise through them and matching the resulting spectrum analysis.
  • Jonas_hJonas_h Posts: 2
    \Jerome King\ wrote:
    This is not missing functionality. There is no such thing as Q for a shelving filter. Q is a function of bandwidth of bell curves as you see in parametric filters. Bandwidth does not apply to a shelf.
    I think that best you can do is match the EQs up visually or by sending pink noise through them and matching the resulting spectrum analysis.
    That was my understanding as well. But I wonder how it is implemented in the DSi amps then.

    I have used measurements for setting up the speaker now and it sounds great. But I would still like to have the original settings just to make sure eveything is as JBL wants it do be.
  • HARMAN_Jerome_KingHARMAN_Jerome_King Posts: 328
    That would be a question for Crown...
  • rabierabie Posts: 1
    These diagrams illustrate how signal is routed through the three different mixer processing objects.
  • bFoozbFooz Posts: 1
    useful post
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