Question about mixdown waveform

[mikew]

Hi all,

Quick question about the initial mixdown of my waveform here. I think I have the mix pretty good except for the bass and cello competing but when I did my first mixdown on this project of ours, I noticed the bottom wave and top wave are not equal. I did some reading and apparently the bottom half of the wave is the lack of pressure in a wave and the top part is the increase in pressure. This does not translate well in my brain when looking at it in the program though. Is it a phase problem? The parts it happens on are large cymbal crashes. I recorded with two overhead mics, one on the snare, one on the high and low tom and one on the kick. Here is a my mixdown wave:

 

[ssscientist]

That image is well within the range of normality.

Before the last, say, 10 years or so all music was mixed by ear. Now since we can see representations of our mixes we think that they should carry more weight than what our ears tell us. If we were making wav files as art, that would be true.

We're making music so what our ears tell us is 95% of what matters. We can use frequency analysis, 3D frequency analysis, inside out and upside down DC offset analysis and many other arcane data manipulations to display what's right or wrong with our waveforms but as a very wise man used to say, if it sounds good it is good.

You already know what the problems are in this mix because you said it yourself. The bass and cello are competing. If you can, do another mix separating the two with EQ or panning or both. If you can't, set it aside and do better next time.


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[mikew]

Thanks Scientist,

I was asking a question indirectly so I should have clarified. I agree 100% that mixing is about making the song sound good. The reason for my question was because I could not get my compressor to clamp down on the spikes. It appears to only operate on the lowest spike of a given wave. I don't plan on compressing this song, I was just using it for example. My compressor settings are probably wrong so I'll fiddle with that some more.

Regards,

- Mike

 

[Freudian Slip]

Set your compressor's operation mode to peak. That is if you have the option. Another thing that could be a problem is if you have your attack set up too slow.

With out being there it's hard to say, but I vote you need to switch to peak.

You may want to go into the individual tracks and manually knock down the 2 or three transiants that are out of wack with the rest of the levels.

F.S.

 

[ssscientist]

Use the zoom feature of the wav editor that made that screen shot, and zoom right in on the three serious spikes.

Select them and the area right around them from wav valley to wav valley so that you have nothing but the spike selected.

Then use the 'amplify' or 'volume' feature of the editing program and set it to a negative value, say -3dB. This will knock down the level of the offending spike, and with a mild setting like that you can process it again if you feel it needs it.

I need to point out that the small spikes in the waveform are just byproducts of the recording process, that they're inaudible to any listener and that no compressor has a fast enough attack to catch all of them. If you were going to eliminate all of them you would need one of the limiters that has 'look ahead' capability. In my experience, clamping such a limiter on a mix creates more problems than it solves and, again, you mix with your ears and not with your eyes.

All stereo mixes have unevenness between left and right --- it's just the nature of the beast and has nothing to with phase or any other problem.


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[a27thletter]

just a quick question that goes along with this post, sortof. In adobe audition 1.5, when i get a mixdown that has a few sudden spikes like that one does i usually go into the amplitude effects and select the hard limiter and then set it to limit the max amplitude to the loudest point under the peak, it then knocks down the peak to the max level of the rest of the wav. then i normalize the whole wave to 100%,.. just wondering if this is an acceptible method or if i'm doing this all wrong.

 

[SouthSIDE Glen]

just a quick question that goes along with this post, sortof. In adobe audition 1.5, when i get a mixdown that has a few sudden spikes like that one does i usually go into the amplitude effects and select the hard limiter and then set it to limit the max amplitude to the loudest point under the peak, it then knocks down the peak to the max level of the rest of the wav. then i normalize the whole wave to 100%,.. just wondering if this is an acceptible method or if i'm doing this all wrong.

Sure, that's perfectly acceptable as long as it sounds OK. It's a good way of taming the wildest handful of peaks before actually moving to your ear to determine the rest. But I wouldn't recommend mastering by sight to be the end of it before normalizing.

G.

 

[MadAudio]

I concur. Looks like 5 or 6 transient peaks that could probably be tamed with volume envolopes on the individual tracks instead of squashing the whole mix with compression. The usual suspect would be drums.

 

[mikew]

Thanks for the info guys. I never thought to use the volume envelopes! a27thletter brings up another question about limiters. I have a Hard limiting plugin with Adobe Audition 2.0 that does have a lookahead option. I never use it perhaps because it says "Hard" Limiter. I figure this would effectively bring the ceiling for the audio down to whatever the limit is effectively clipping the audio. I suppose it just puts some mean compression on it when it hits the limit?

- Mike

 

[SouthSIDE Glen]

I figure this would effectively bring the ceiling for the audio down to whatever the limit is effectively clipping the audio. I suppose it just puts some mean compression on it when it hits the limit?

Kinda true. "Hard limiting" in general referrs to a type of compression with a very high ratio (easily 15:1 to 40:1), typically with a hard knee, and always with very fast response (attack) so that no transients sneak through.

While I can understand what you're saying when you say "effectivly clipping", that is not technically quite correct. You can use that as a very rough image if you wish, but don't take it literally, as clipping *is* different from even hard limiting and will have a different sound.

G.

 

[Farview]

Some instruments and voices do not create a balanced waveform, they just have more energy one direction than they do the other. Compression can make this worse, letting the initail transient through and clamping down on the negative swing of the wave.