When is Clipping a penalty?
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  1. #1
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    Default When is Clipping a penalty?

    Just wanted some opinions on the topic and/or some reading from either an article on this website or another one that further explains clipping.

    I DJ with a buddy sometimes at a bar on the weekends. We have 2 ideas of when the music or power output is actually clipping. We use 2 Crown XLS 802 power amps and a Numark M3 mixer. Neither one of us clip on the amps (usually turned about halfway up), but the mixer is a different story. When I'm playing I try to keep it out of the red, maybe touching the first red occasionally, but when he plays he cranks it and usually has the mixer hitting the 3rd red a lot (9 yellows, 3 reds).

    It is definitely louder when he plays, but I really can't say that I hear the sound is cutting any highs out. He says it's only clipping if the amps are showing it by the designated clipping light. I always thought it was clipping and therefore cutting frequencies when the amps and/or mixer showed it (through the visual lights). So who is right? Thanks.

  2. #2
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    i'm on your side, but let's wait for an answer from someone more in-the-know.

  3. #3
    DJTT Moderator Dude Jester's Avatar
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    Ignore the red lghts on the mixer, its the amp/speakers you need to keep an eye on dude.
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    Tech Guru djproben's Avatar
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    The amp can only work with what the mixer gives it, so if you're clipping on the mixer it's going to sound crap even if the amp is not cranked up. But there's probably more headroom on some mixers than you think -- the numbers of LEDs on these meters are far from standardized. So it's possible that your mixer isn't really clipping even if it's in the red while another might. Me I always try to stay out of the red but I frequently see DJs who are all up in it. You should be able to tell right away if it's clipping significantly.

    Heh what would be really cool is if DJ mixers had good old classic analog VU meters instead....

  5. #5
    Tech Guru exokinetic's Avatar
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    You are absolutely right.

    The Crown amp's clipping light is based on how much voltage that amp can apply to ANY signal before THAT amp starts "clipping".

    If you are already sending a clipped signal to your Crown(i.e. running the DJ mixer in a clipped state), but you are running you Crown within its operating range, it will not show you a clip indication.

    Though you WILL be sending a clipped signal to your speakers, and this WILL wear them out prematurely. To much clipping can result in speaker failure very quickly.

    If you are only clipping the mixer mildly then the audible result will be minor, as the actual frequencies being removed are at the extreme top and bottom of the hearing spectrum.

    As a rule of thumb, regardless of the LED placement on the mixer, I try not to let it peak above +3db at either stage, channel or main.

    I have heard arguments for 6db that stand to reason, but I REALLY think it depends on the mixer. Its unfortunate that we don't know the exact clipping point for a specific mixer, although every manufacturer documentation will tell you to avoid allowing the signal to hit the red as it will 'risk' clipping.

    With that being said. This is clipping in a nutshell:


    When a sine wave (audio signal) is clipped the very top of the wave, that should be a progressive curve, gets flattened, to reduce the highest points.

    BUT at the point where this sine wave is flattened into a "square" wave, the actual electrical voltage that is telling the speaker it should be reaching the top of the waveform is still going through the voice coil, BUT the speaker doesn't actually move that far, it only moves as far as the clipped signal allows.


    Speaker voice coils are cooled by the air that the actual cone of the speaker pushes past it as it operates. SO, if the signal is clipped, you are running voltage through your speaker, and that speakers cone is NOT moving as far in and out as it should for that voltage, so the voice coils will begin to overheat, because their cooling ratio is very fragile.


    So you might not hear it cutting out audible signal when your friend is clipping the mixer, but it is DEFINITELY putting a lot more wear on the speaker system being used, and if that is done every night, for a majority of the night, that speaker system will come apart way sooner than it should.


    And if you didn't know exactly what clipping your mixer was, you would just assume you had gotten bad speakers, or you would have a bad impression of the company you got your speakers from, for an unfounded reason.
    Last edited by exokinetic; 02-09-2011 at 02:14 AM.

  6. #6
    Tech Guru mostapha's Avatar
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    Quote Originally Posted by exokinetic View Post
    Its unfortunate that we don't know the exact clipping point for a specific mixer, although every manufacturer documentation will tell you to avoid allowing the signal to hit the red as it will 'risk' clipping.
    Actually, you can figure it out. Find any subtractive synth plugin and generate a sine wave that does not clip when rendered. Aim for it to be as loud as possible without intersample modulation distortion or clipping, or about -3dB as a general guide if you don't know how to test for that. It doesn't really matter what frequency you use, but I'd make separate ones at 110Hz, 440Hz, and 7040Hz if I knew nothing else and wanted to be thorough.

    Burn a couple minutes of it to a CD or put it into traktor or whatever. Set up your sound system the way you normally would with the channel gain all the way down and the EQ flat. Then start playing them with every feature off: 0% pitch, keylock off not gridded, all limiters off, etc.. Have somebody watching the amp level to make it loud enough to hear clearly but not loud enough to hurt, and don't let the amp clip, because that will defeat the purpose of the test.

    Then just start turning things up. You'll hear it start clipping, though if your ears are shot, you might have questions about where it starts.

    It doesn't take more than about 2 or 3dB of clipping to become painfully obvious if it's a digital mixer with no soft-clipping protections. With analog stuff that's made to clip in a pleasing way, it might take a bit more gain overlap to make it painfully obvious, though you should still be able to hear only a couple dB.

    When you figure out where the mixer starts clipping, take off another dB or two as a safety margin…put a sticker on the level meters that caused it (all channel meters and the master meter are good places for them) and never peak above that level. If you need it to be louder, get more powerful amps or turn them up more (also, never clip them…though you can probably trust their lights if you've read the manual and know what they actually mean).

    That way, you'll get all the dynamic range out of your system that you can without squashing the hell out of your signals, wearing the speakers, or fatiguing people's ears.

    Just a quick note and something most of us are familiar with…Traktor clips sound card outputs if it peaks above about -0.2dB. The apparently negative headroom is probably the result of intersample modulation distortion, but it sounds like crap if you let it clip at the output…and its limiter doesn't sound much better. Based on my tests, the highest Traktor's master output should ever be set is about -14dB, though if you have enough quiet (as in noseless) gain on your DJ mixer (or whatever gain stage is after your master output if you're using a controller) and you're using 16-bit files, you can run it down to about -40dB before you lose any dynamic range. That number (-40) is based on the assumption that Traktor works similarly to most of the popular audio processing stuff out there and some basic testing that showed me it was at least that value if not even lower. But -14ish dB works fine.

    How much does it matter?

    Well, I think it matters a lot, but…I also haven't been in a club without earplugs since 2004 to protect my hearing. Despite owning very good musician's earplugs, I almost always wear $15 hearos earplugs because they roll off the highs more. I have yet to go see more than 2 or 3 DJs that didn't clip the shit out of the mixer. A couple weeks ago, I had an interesting conversation with a promoter wondering why the sound system sounded weird…the reason was because he'd never heard what dance bass sounds like if you're not clipping the DJ mixer by running it into the red and turning up the bass EQ, eliminating any semblance of dynamic range on the low end. Apparently, he'd never heard a subwoofer not distort before.

    So, obviously it doesn't matter that much if you're okay with fatiguing everyone's ears, costing venues and promoters money in damaged cones, and sounding no less like crap than everyone else. It's not a huge degradation in sound quality for most people who've already damaged their hearing anyway. But if you understand it well enough to explain it, there's not really a reason not to unless you're going to get fired for doing things right…which I could see happening if the promoter is really dumb.

  7. #7
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    when using A&H mixers, if theres any red on the mixer, your pumping out shite. when using Pioneer mixers, you cant really trust the meters, well the master ones, because of the master attenuator on the back, depends where it is set.

    Clipping on the amp is bad, clipping in any form is bad. your basically trying to get the speaker to do something it can't and after prolonged clipping, it will give way
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    DJTT Moderator bloke Karlos Santos's Avatar
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    Clipping is bad. Simple as.

  9. #9
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    When is Clipping a penalty?
    If your not getting paid 5 figures per gig..... Always

    Amp up - Mixer master down is the best way to play it.

    Red = Warning since the dawn of time and most DJ mixers will sounds REALLY rough at the +6 level (Vestax and Pioneers IMHO being the worst offenders).

    The only mixer I've ever heard that sounds pretty much perfect when the master output is in the red was a Formula Sound, but if you clip the individual channels at all it'll sound shite as anything else.

  10. #10
    Tech Guru exokinetic's Avatar
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    Quote Originally Posted by mostapha View Post
    Actually, you can figure it out. Find any subtractive synth plugin and generate a sine wave that does not clip when rendered. Aim for it to be as loud as possible without intersample modulation distortion or clipping, or about -3dB as a general guide if you don't know how to test for that. It doesn't really matter what frequency you use, but I'd make separate ones at 110Hz, 440Hz, and 7040Hz if I knew nothing else and wanted to be thorough.

    Burn a couple minutes of it to a CD or put it into traktor or whatever. Set up your sound system the way you normally would with the channel gain all the way down and the EQ flat. Then start playing them with every feature off: 0% pitch, keylock off not gridded, all limiters off, etc.. Have somebody watching the amp level to make it loud enough to hear clearly but not loud enough to hurt, and don't let the amp clip, because that will defeat the purpose of the test.

    Then just start turning things up. You'll hear it start clipping, though if your ears are shot, you might have questions about where it starts.

    It doesn't take more than about 2 or 3dB of clipping to become painfully obvious if it's a digital mixer with no soft-clipping protections. With analog stuff that's made to clip in a pleasing way, it might take a bit more gain overlap to make it painfully obvious, though you should still be able to hear only a couple dB.

    When you figure out where the mixer starts clipping, take off another dB or two as a safety margin…put a sticker on the level meters that caused it (all channel meters and the master meter are good places for them) and never peak above that level. If you need it to be louder, get more powerful amps or turn them up more (also, never clip them…though you can probably trust their lights if you've read the manual and know what they actually mean).

    That way, you'll get all the dynamic range out of your system that you can without squashing the hell out of your signals, wearing the speakers, or fatiguing people's ears.

    Just a quick note and something most of us are familiar with…Traktor clips sound card outputs if it peaks above about -0.2dB. The apparently negative headroom is probably the result of intersample modulation distortion, but it sounds like crap if you let it clip at the output…and its limiter doesn't sound much better. Based on my tests, the highest Traktor's master output should ever be set is about -14dB, though if you have enough quiet (as in noseless) gain on your DJ mixer (or whatever gain stage is after your master output if you're using a controller) and you're using 16-bit files, you can run it down to about -40dB before you lose any dynamic range. That number (-40) is based on the assumption that Traktor works similarly to most of the popular audio processing stuff out there and some basic testing that showed me it was at least that value if not even lower. But -14ish dB works fine.

    How much does it matter?

    Well, I think it matters a lot, but…I also haven't been in a club without earplugs since 2004 to protect my hearing. Despite owning very good musician's earplugs, I almost always wear $15 hearos earplugs because they roll off the highs more. I have yet to go see more than 2 or 3 DJs that didn't clip the shit out of the mixer. A couple weeks ago, I had an interesting conversation with a promoter wondering why the sound system sounded weird…the reason was because he'd never heard what dance bass sounds like if you're not clipping the DJ mixer by running it into the red and turning up the bass EQ, eliminating any semblance of dynamic range on the low end. Apparently, he'd never heard a subwoofer not distort before.

    So, obviously it doesn't matter that much if you're okay with fatiguing everyone's ears, costing venues and promoters money in damaged cones, and sounding no less like crap than everyone else. It's not a huge degradation in sound quality for most people who've already damaged their hearing anyway. But if you understand it well enough to explain it, there's not really a reason not to unless you're going to get fired for doing things right…which I could see happening if the promoter is really dumb.

    Very informative post man, thanks!

    Great idea one measuring the clip point on a specific mixer, will be doing that on my Behringer today.

    Also a very good insight on Traktors negetive headroom, witch I have been expecting as the case for while, I usually run the traktor gains at -3db but that only limits the main body of sound to -3, transients will peak just below 0db, witch causes a disgusting clip, witch gets a lot worse, if you are clipping two channels internally in traktor.


    The -14db suggestion I'm going to do some serious testing on as well, this seems to make a lot of sense, and the gain knobs on my behringer are surprisingly quiet.


    And is it Traktors extreme bit depth (witch allows for something like 200+db of dynamic range) that allows you to run the internal traktor master gain at -40db with ought squashing the dynamic range?


    ...Again thanks for the insightful info!

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