Subject:Clipping - ALWAYS bad?

Posted by: spinweb

Date:3/10/2005 10:48:20 AM

I have a mixing-related question.

I read in Sony's ACID Pro 5 - POWER! book that Clipping is always bad and results in a loss of digital data.

Is this always true? I thought I saw my engineer at the studio running things really in the red. Perhaps that was analog? I thought I read that sometimes it's a good thing.

And let us not forget that Nigel in Spinal Tap ran his amp to eleven.

:)

Eric

Subject:RE: Clipping - ALWAYS bad?

Reply by: Klirrfaktor

Date:3/10/2005 11:01:21 AM

personally i try to not reach RED in acid.. but some stuff you have to set into red to get the correct sound. specially low frequencies i do overload for good results. this is all depening on the music style you want to do.. if you are into gabber or hardcore.. forget about the 0db marker. more red = more power :-) but in "normal" music im trying to get the power with help of compressors and limiters. actually, acid does NOT clip/crackle/click when you work in the red area of volume and you do a mixdown/rendering.

Subject:RE: Clipping - ALWAYS bad?

Reply by: JohnnyRoy

Date:3/10/2005 11:04:08 AM

> Nigel in Spinal Tap ran his amp to eleven.

Yes, but Nigel was living in the analog world where eleven is... well... one louder. Isn’t it.

In the digital domain clipping is always bad. Here’s why:

Digital use a measurement system known as Full Scale (FS). 0dB FS is at the top of that scale. There is nothing above it. If you pass that limit, there is no way to represent those bits and so information is lost forever. This is BAD!

Analog uses a measurement system known as Volt Units (VU). 0dB VU equates to –20db FS (this is a recent standard so some older equipment may equate it to –18dB or –24dB etc. but the standard is now –20dB). The VU scale goes up to +12dB VU so 0dB VU is NOT at the top of the scale. 0db VU is the point at which analog tape saturation happens. The reason you heard clipping was good is because our ears like the sound of a little tape saturation. It somehow sounds warmer to us. So in analog it’s OK to exceed 0dB up top +12 dB.

Bottom line is: Never exceed 0dB FS (i.e., clip) in the digital world.

~jr

Subject:RE: Clipping - ALWAYS bad?

Reply by: Klirrfaktor

Date:3/10/2005 11:15:42 AM

"If you pass that limit, there is no way to represent those bits and so information is lost forever"

sometimes exactly that is what sounds cool ;-)

Subject:RE: Clipping - ALWAYS bad?

Reply by: JohnnyRoy

Date:3/10/2005 11:23:36 AM

If you want your music to sound more powerful, lower the threshold on your compressor. This will squeeze the dynamic range bringing lower sounds closer to 0dB while maintaining the higher sounds at 0dB. (I actually like to mix for –0.3dB just to leave a little headroom).

If you have Wave Hammer, go into the Volume Maximizer and reduce the Threshold and you’ll hear everything get much louder without clipping. Of course if the sound of clipping is what you’re after then go for it.

~jr

Subject:RE: Clipping - ALWAYS bad?

Reply by: spinweb

Date:3/10/2005 2:04:40 PM

___________________________________________________________________

If you want your music to sound more powerful, lower the threshold on your compressor.
___________________________________________________________________

That reminds me of a compression problem I mentioned in another thread. I think you advocated using an automatable FX for compression? I tried lowering the attack to 0 and that helped, but I still get a big surge when the signal first comes in.

Subject:RE: Clipping - ALWAYS bad?

Reply by: DKeenum

Date:3/11/2005 7:46:02 AM

Search the web for tutorials on compression. Was it on the Computer Music web site? I can't remember, but I know it is out there... somewhere.

Subject:RE: Clipping - ALWAYS bad?

Reply by: Illogical

Date:3/11/2005 7:52:01 AM

I always try to avoid clipping, but I gotta say that a quick +.5db on a snare or kick hit doesn't really jump out at me as grating. Maybe my ears need better training, but it seems like a big hit kind of masks any of the clipping sounds, provided it's not a sustained sound.

One related question, what if you're getting clipping on the input for a compressor, but it's under the red on the output. Has clipping still occurred, or does the compressor sort that out? Same question on other effects, and busses...if a bus clips, but the master doesn't, what has happened?

Just to clarify, I can hear digital clipping and know it sounds bad, but these brief spikes don't seem to sound as terrible as everyone claims.

Subject:RE: Clipping - ALWAYS bad?

Reply by: Iacobus

Date:3/11/2005 11:41:33 AM

Bear with me as I'm not an audio engineer. I'm just a lowly musician. :)

From a logical standpoint, whatever goes in is what comes out. In this case, if there's a clipped signal going in, it's merely being amplified when going out. It may technically not be clipping, but it should sound like it is.

You know what they say: Garbage in, garbage out. :)

Iacobus
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