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Legitimate gain procedure?

DraDra Posts: 3,777
Seeking input to see if my logic was good.

Finally got arround to setting my mixer, 260, and new PLX3102 amps gain structure. After getting the board LED's, 260 in / out meters (GUI) to -0-, I had a thought. This is what I did...
I forced the board into HARD clipping (95% on) (only 1 red above +9).
Then made sure that the 260 input peaked at +18, same on the outputs (with limiters on).
The amp clip LED's are variable in their illumination with the level of distortion and they were flashing a pale pink.


Thoughts :?:
Ideas :idea:


DRA

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    GadgetGadget Posts: 4,915
    YO!

    Bet you didn't expect to see ME show up here... ya right :lol: Well, fine but with a qualification... NO CLIPPING IN THE Driverack EVER! oops... :oops: didn't mean to yell...but as always we have lots of lurkers and I cannot stress enough that there is a HUGE difference between analog clipping (considered warm and compressed sounding) and Digital clipping :shock: HORRIBLE, speaker damaging sound... HARSH... no no no... so with the mixer in soft clip, bring the 260 back a little...remember in a digital domain it's not critical to have a high signal to noise ratio... since theoretically there IS no noise...I would like to see at least 4-6 db of headroom actually...

    As for the limiter... I can't say thats how I would suggest doing it...I would rather see the gain structure set with the limiter OFF... then find the level you want to run your shows (within the limits of the gain structure) and set the limiter up to just start hitting at that point, that gives you a slight additional gain but the artifacts of the limiter are not evident (that squashing sound...audible pumping like sound the higher we go into clipping. But then I like a very live, uncompressed airy sound...your mileage may vary...if you want that compressed sound without using a compressor, set the limiter lower and drive into it a bit, you'll get that squashed plastic sound you've been looking for :lol: only without the feedback potential that compressing brings to the table...

    Cheers...

    Gary...
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    DraDra Posts: 3,777
    I assumed that +22db was the clip point. But as the manual says +20db. DUH :?
    So now that +20 is established. The goal should be +12 (not 18)continuous and avoid any +18 ignition at all (since that limits me to 2db headroom) as a worst case scenario. I theorize that a constant +12 is bumping +15 db. That could be confirmed by how much the input mixer is reduced to get to the new set point.
    So I was using the right equation, but using the wrong number for \"X\". So I missed the problem. Maybe the teacher will give partial credit.

    As far as the limiters go, they were triggering but were not going into reduction yet. And like I said, I had the board waaaaay hotter than I would ever push it (95% on with the only red LED and I would never go beyond a 5% \"blink\". OK maybe a 10% \"blink\", if needed.

    Thanks,
    DRA


    Current system:
    Mains-
    260
    PLX3102 stereo 600w - Yorkville E12 (pr) 400w program
    PLX3102 stereo 600w - Yorkville E12 (pr) 400w program
    AP3000 bridged 2400w (4 ohm) - Yorkville subs (pr) 800w program

    Monitors-
    DRPA - 1 mix
    Yorkville NX25P (pr) (200w bi-amped poly-cab)
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    Fanman20Fanman20 Posts: 223
    An interesting article on clipping

    http://en.wikipedia.org/wiki/Clipping_(audio)



    I have heard from a source, forgotten where from, that digital clipping is the biggest no no in audio.

    I should set up gain structure so everything clips (analogy) at the same time except for digital equipment which should be a few db down. And watch for transient clipping

    Is this a correct philosophy???????

    Mark
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    GadgetGadget Posts: 4,915
    Yes, that is the correct way to do it. Analog clipping has long been viewed as warm \"acceptable\" type of sound embellishment. Digital clipping however is a horrible equipment taxing sonic bombardment worse than pink noise...Kind of like the evil twin of pink noise...

    Gadget
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