2015-03-04

Golden Eyes: Experiments with Audio - Part 3 (phase inversion, inverse phasination)

(It is recommended to read part 1 and part 2 beforehand.)

OK, let's subtract the clipped track from the original track to see only the differences. How do you subtract one audio from another? Well, you invert one of them and then 'sum' them!

Here is a small portion of our original vocal part:

 "eieieieieiiii" in about 50 ms

And here with the phase inverted version:

Like looking in the mirror!

In Cubase you can select the audio clip and apply Audio->Process->Phase Reverse to get the inverted version. Notice how it is inverted by the 0-dB-axis. Now, what if we play both at the same time? As you can guess, the answer is "complete silence" since the waves will superimpose and cancel each other completely! Let's bounce the summation result:

Silence...because, science! :)
So, in a way if A' is the phase inverted version of A, we confirm A + A' = 0. What about our clipped track in the previous part? Here another part from the vocal from the clipped track and compared with the original track:

Looks like digital clipping to me

Remember the 'shaving'? Now, let's see only the clipped parts by taking the difference (summing with the inversion of the original):

Ahh, so this is the place where all those clipped data was going after all!

Now we can clearly see what exactly is being clipped in track C. Notice that the weird bounce-back dips we have talked about in the previous part are also clearly present in the difference. Pretty neat, don't you think? In the next part, I will investigate an interesting 'process' on the original.

Continue with part 4.

Cagil


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