Waveform Shift Question??

djwc101

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#1
Waveform Shift Phenomenon??

I've noticed in many tunes by the likes of Noisia, Phace, and etc at certain points in the track the waveform will move off center. At first glance it appears to be pan or stereo modulation, but after experimenting that doesnt seem to be the case.

Kinda hard to explain so here's an example
["Misanthrop - Factory 9" intro]

AUDIO CLIP:
http://dnbshare.com/download/Misanthrop_-_Factory_5_INTRO_CLIP_.mp3.html

If anyone could tell me whats going on here and if this has any real effect on the audio, it would be greatly appreciated!
-thanks
 
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subprime

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#3
Every now and then if I'm resampling a rendered clip will look like this and I pretty much say what Miszt just said.

Looks strange as hell for sure.
 

kama

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#6
Sometimes plugins that simulate analog signals can do that. Stuff like "tape distortion" or something. I'm not sure exactly what it is though. DOA had an extensive thread on the subject with the pro's trying to explain it. Hard to find without knowing what it's called.
 

djwc101

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#7
whats the time span for that pic?
about 24 sec


Sometimes plugins that simulate analog signals can do that. Stuff like "tape distortion" or something. I'm not sure exactly what it is though. DOA had an extensive thread on the subject with the pro's trying to explain it. Hard to find without knowing what it's called.
Hmm makes since for the most part, by why would analog/ distorted signals do that :-/

It would be a huuge help if you could find that DOA thread!!
 
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djwc101

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#9
here's another example, not as good as the one before but ya get the point..

[2nd half of drop on "Scary Monsters & Sprites (Noisia Remix)"]


---------- Post added at 17:36 ---------- Previous post was at 17:22 ----------

what does it sound like? can u put a clip up?
Just added it to the original post^^
 

tv_g

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#10
it's a number of really low frequencies (less than 1hz). since it is way, way below the audible range, it is eating headroom and should be filtered out. you can see in both these cases that one side is getting heavily compressed/limited and the other side is not.

in soundforge, use the fm synth to generate the lowest possible simple sine wav and mix one cycle (or part of one cycle) into your tracks and the wave form will now look similar to that.

the only use i've had for this (as it usually occurs as a side effect of reverb or convolution) is in changing how a compressor or wave shaper works (amplitude based plugins) and then filter it out after.
 
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miszt

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#11
thanks for the info tv_g, aware of low-freq problems like this (didnt know it fuked the waveform like that tho!), just seems a bit unlikley for it to be found in a released Noisia track?
 

djwc101

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it's a number of really low frequencies (less than 1hz). since it is way, way below the audible range, it is eating headroom and should be filtered out. you can see in both these cases that one side is getting heavily compressed/limited and the other side is not.

in soundforge, use the fm synth to generate the lowest possible simple sine wav and mix one cycle (or part of one cycle) into your tracks and the wave form will now look similar to that.

the only use i've had for this (as it usually occurs as a side effect of reverb or convolution) is in changing how a compressor or wave shaper works (amplitude based plugins) and then filter it out after.
BINGO!! After putting a high pass at 20hz on both of these tunes it fixed the waveform right up. Also tried adding it to a couple of my own tunes and got some crazy lookin results.

Still raises the question though.. Why would audio extraordinaire's like Noisia let something like that slip thru in the mix?? Either it's for some weird subconscious effect OR they just like fukkin with the waveform for fun lol.. both very likely

Bigg ups to tv_g for your reply! :)
 

kama

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Hmmmmmm. Could it be from the mp3 conversion? Are these wav's or what? Also, ripping from vinyl could introduce something like that I imagine.
 
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#15
If any wants to look it up it's called DC Offset and it's undesirable. Imagine the speaker being limited to that small range of motion instead of crossing the origin (its resting place).

I've had this problem recording analog->computer in general (most likely caused by some bad power, wall warts, old equipment, computers, lights...etc...) from vinyl and from synthesizers. Actually, if someone can tell me why the "remove DC offset" function in Cubase doesn't work that would be really helpful. I don't want to have to run it through pure data with a HPF @ 5Hz. What other programs have a good HPF to remove the DC offset? Set it as low as possible cause it will "change" the rest of the waveform according to experts.
 

tv_g

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#16
Set it as low as possible cause it will "change" the rest of the waveform according to experts.
yep, most high pass filters cause small time shifts in frequencies above the cut. so especially in the bass you'll see interference compounding or cancelling certain frequencies as the phase changes.

i've never had to remove low frequencies from anything other than samples where i do not care much about this. on a whole mix, i would be very hesitant, but 5hz shouldn't be too bad. this does lead me to think there should be some dc offset specific plugs but i do know any.
 

djwc101

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#18
So since there's not much to do around my neck of the woods today, got bored and started messing around with different DC Offset combinations...
and uhhh all I have to say is...


..guess I got a lil carried away :lol:
 
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#20
huh, try doing that above audio rate like 80Hz or so and see what it sounds like

---------- Post added at 15:30 ---------- Previous post was at 15:27 ----------

Oh, and tv_g, as it seems you may know, I'm wondering if I should avoid making these drastic low cuts and subtractive cuts in the equalizer - both on the master and individual tracks. AFAIK what you're implying is that my lo-cut around 35Hz could be messing things up a bit?

I guess the question is whether digital equalizers make some effort to maintain good phase no matter how they're used.

Sorry that's off topic.
 
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