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Bandpass signal loss

BobeccaBobecca Posts: 14

Can somebody clear up one thing for me, namely, is it necessery to adjust the loss in bandpass reduction in the signal of 260?

If I have my crossovers in the out position(full band) I have a perfect signal going in to my amplifier. In and out in 260 is egual, meaning unity gain.

If I choose a limited band, for an example, 80-350Hz then I am lossing signal in the output and have that loss in to my input of my amplifier.



  • DraDra Posts: 3,777
    Let's put it this way...
    Would you adjust the gain up and down during the bass players solo as each note is being played?

  • BobeccaBobecca Posts: 14
    To answer your question then it is no. But when following the procedure in that link, there is no way that I can have the amps to clip at the same time and using the setting from JBL for my speakers.

    The setting says that my crossover gain is -1,5 dB for the 15" base modul and +0,5 dB for the top. All my amps have equal fixed gain of 26dB.

    I am kepping this simple to not add to any confusion in the discussion. I can come back later with speaker and amp model :mrgreen:
  • DraDra Posts: 3,777
    If your amps and speakers are in the harmon family, the numbers can be trusted a little more than if they're not. Usually though, those numbers are generated by math and not real world. With fixed voltage gains you will have to use the x-over gains to check the clip timing. Note: The clip test is to set the maximum level of each amp, THEN music can be used to balance the outputs (x-over gains) by LOWING the one that is louder (not increase the weaker).

  • BobeccaBobecca Posts: 14
    Yes, the amp and speaker are all in the harman sphere. The setting for the timing is there as well except for the level of clipping which I set indvidually.

    As I see it, in the 260 there is no other way to compensate for the loss in signal other than to raise the crossover gains and deviate from the actual setting from speaker manufacturer. If I would have the 4800, and it has an output gain that can be adjusted looking at the block diagram, does mean that the level can be increased prior sending this signal to the amp. This is what I feel is missing in the 260 or would like to have implemented in 260.

    What I have to do is to change the input sensitivity to raise the signal in the amp, change this to another value of fixed gain from 26dB to 32dB and adjust output level on the amps to match the overall loudness level.

    My understanding is to have the same value of fixed gain in the amps. It is not in the amp the problem lies but rather in the 260 as I see it.
  • DraDra Posts: 3,777
    Sounds like you have this (for example)...
    Input meter: +12
    Output meter (low): +6
    Output meter (high): +3

    ...and this is what you want...
    Input meter: +12
    Output meter (low): +12
    Output meter (high): +12

    If so, you will need to raise the x-over gains... +6 for lows, and +9 for highs.


    PS - from an earlier post: You said the amps can't clip at the same time. We are not talking about each amp clipping at the same time as the other amps. We are talking about the amps clipping only if the mixer is clipping (hard in the red).
  • BobeccaBobecca Posts: 14
    Like you describe is what I have. So basically I have to deviate from the actual setting and raise the x-over gain and keep the amp voltage gain equal on my amps. Or leave the unevenees in signal chain and keep the voltage gain equal and call it the day.

    But the procedure of gain structure offering by the 4800 is a better approach then 260. At least one is making the gain structure within the 4800 which I think is the way to go.

    I will come back with all the settings and what gear I have for an clearar picture.
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