A look at your limiter (visual reference)

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A look at your limiter (visual reference)

Postby loudsubz on 13 Apr 2013, 22:21

For some who don't know what the limiter does, or how it alters the waveform, I was messing around with my xponent today and pulled out my o-scope to grab some shots of what it does in real time.

To start off, I ran a 1 khz tone (0dbs) through CrossDJ and turned off the limiter. The gain was at 0 and the volume was max. You can see its at the limiter just before clipping.

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And this is what the output waveform looks coming out of my audio sound card. (notice the nice smooth peaks, no plateaus, just nice crest and back down again.

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The next one is where I bumped the gain a bit and it started to clip. Notice only 1 block of red is clipped, but it still plays a role on the audio output.

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Here is what the output wave file looks like:

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Notice how its not as smooth at the crest any more? It is starting to develop a flat spot which means the drivers (woofer) is not making a smooth in and out transformation any more, but instead the woofer is pushing in/out and resting for a split second before continuing in the opposite direction. This means the voice coil starts to heat up because it isn't being vented properly with the velocity caused by the woofer going in and out, and that's how the voice coils burn up.

I continue on a bit more and the waveform started to get even flatter and flatter. Eventually the audio will sound very terrible and its only a matter of time before your speakers stop working.

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Once I turned the limiter back on, the same clipped signal was now a smooth sine wave again.

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I did notice that on the down slope on the right side of the wave, there was a slight linearity issue that was very small, but I rather ave that than a clipped signal destroying my speakers.

Hope this helped some visualize whats going on in your audio chain.
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Re: A look at your limiter (visual reference)

Postby daniel clark on 14 Apr 2013, 00:58

:cool: this a perfect tutorial ,,thanks ,, glad to see what your ears should hear :eek: :idea: :!:
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Re: A look at your limiter (visual reference)

Postby Alexkidd on 14 Apr 2013, 11:42

beautiful tutorial. Knowing what happens and seeing it are two different things so thanks for the example and the pics.
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Re: A look at your limiter (visual reference)

Postby Jim B on 14 Apr 2013, 12:25

Very interesting indeed.
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Re: A look at your limiter (visual reference)

Postby acemc on 14 Apr 2013, 20:00

Thanks for this. Great tutorial.
Would you care to do test to check for any level increase when scratching ?
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Re: A look at your limiter (visual reference)

Postby daniel clark on 14 Apr 2013, 20:31

:eek: :?: :idea: :!:
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Re: A look at your limiter (visual reference)

Postby sylMV on 14 Apr 2013, 20:51

acemc wrote:Thanks for this. Great tutorial.
Would you care to do test to check for any level increase when scratching ?


Are you kidding me?
I already explained you there were a level increase and gave you the values.
viewtopic.php?f=259&t=27379&st=0&sk=t&sd=a&start=10
By the way this is not a level increase when scratching, this is a level increase following the vinyl speed.
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Re: A look at your limiter (visual reference)

Postby sylMV on 14 Apr 2013, 20:52

Thanks loudsubz for this great analysis!
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Re: A look at your limiter (visual reference)

Postby acemc on 14 Apr 2013, 21:17

I already explained you there were a level increase and gave you the values.

I'm curious to see what the scope shows. Wow, didn't realize it would be a bad thing!
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Re: A look at your limiter (visual reference)

Postby sylMV on 14 Apr 2013, 22:31

Not necessary a bad thing, I just don't get what you're try to find here... as I gave you information from the inside...
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