Audio Recording Tutorial - Phase cancellation, the sound destroyer

#AudioRecording
#HowTo
#LinkedIn

[LukeJF]

"No amount of EQ or processing can ever make it right afterwards"? Yes that's right, but moving one track back or forwards in time so the phase matches the other track can lol

[noelfletcher]

"No amount of EQ or processing can ever make it right afterwards" - try using an invert effect, audacity is free and has one

[Ardeact]

There are ways actually; Some audio editing application can invert phase or set phase by intervals to match up with the secondary mic. Izotope RX7 is great at this and can detect phase issues automatically. Not sponsored btw lol

[TheWaynelds]

Most audio software will have an “invert phase” option for individual audio clips to remedy this. I see phase cancellation occur a lot during song transitions on DJ mixes (Mainly in the Hardcore and Gabber music genre, which uses distorted kick drums and 4 to the floor type beats, so the kick drums from both songs are, more or less, hitting at the same time, with a slight speed & pitch fluctuation caused by the turntables.

[johneygd]

Must be hell to setup every mic at the correct place among with right amplification & sensetivity and right type microphone, phew,
Now i can also understand why you cannot always pickup all sounds from a single mic, all because some certain sounds can unintentially cancle eachother out.

[CaretakersBand]

Good guide but not sure I fully understand. Why can't you fix phase cancellation by slightly adjusting one recording a few ms earlier or later?

[robertozariskeeni]

Hello, i have a question about checking for Phase Cancellation.... How can this be accomplished *without* the use of a DAW?

I am setting up my first Home Recording setup for our band and new to a lot of this and trying to learn. I have a Behringer UFX1204 mixer/audio interface and part of our plan is to do "Live"-type recordings where we mic everything: drums/amps, vocals and do Live takes multi-tracking everything into a DAW (Reaper) at once instead of tracking each instrument separately.

The problem with this is the Interface only has a limited # of XLR inputs (4) so our plan is to mostly use those for mic'ing bass/guitar amps and vocals while using a separate secondary Peavey mixer for the Drum mix and using a 1/4" line from that into the Behringer for a single-track on Drums instead of having each Drum mic with it's own individual channel going into the DAW. (Hope that makes sense?)

Almost all the tutorials i have found on Youtube talk about checking for Phase Issues by looking at the individual Drum mic tracks in a DAW and referencing each of them against an Overhead, checking for Phase issues and playing with the phase switch for each to see what sounds best by ear as well?

Since i won't have individual Drum mic tracks going into the DAW (they will all be reduced down to a single Channel input) and there are no phase switches on either mixer, i'm trying to figure out how I can check for Phase Cancellation issues with our particular setup?

From what i gather, this will have to be done completely "by ear" on the secondary mixer maybe using the same method of referencing all the mic's (Kick/Snare/Tom) against an Overhead and just playing with the mic placement to listen for a "sweet spot" where it sounds best? Does this make sense?

Can't find anything else about doing it this way on Youtube so any links, advice, or suggestions would be much appreciated. Thanks :)

Ps. We will probably be using a pretty simple 4-5 mic setup: Condensers on the Kick and maybe an Overhead or out further in front of the kit, and 2 dynamics on the Snare and Tom...

[DarrellWolfe]

@matako07 There are probably more technical ways to figure this out, but here is the practical way.

#1 just check to see that none of the mics being used are in reverse polarity from each other (that means the manual phase adjuster that flips it 180* hasn't been turned on) (This is usually a symbol which resembles an O with a line through it). This can happen many times in mic placement. If you are using 2 mics on the snare (Top and Bottom) and they are practically facing each other, these could have some full or partial phase relationship. Try re-positioning the mics or flipping on the polarity switch on purpose because the natural placement has caused phase cancellation, so you want the polarity to be reversed. 

#2 try just solo-ing out two channels that you suspect are causing a problem, then flip the polarity on one of them and see if the sound gets suddenly louder or quieter. That would be a sign you have a polarity issue. 

Again, there are a ton of other things that could play out here but these are the two common things that come up in live and in recording. 

[jennifer]

2:23 These mics are shown in their traditional placement positions...which is not the most effective. Traditional piano mic placement has been inadequate for many decades, because it's based in the myth that the sound comes from the entire right side of the piano which is the open lid side. It doesn't. In fact, to hear the true STEREO sound of the piano, one needs to place

a mic 12" over the hammers on the far right side of the keyboard. Then place another mic 12" over the bass hammers on the left side of the keyboard. This will capture the true STEREO sound of the piano, which is exactly the way the pianist hears it when he/she plays it. Low notes on the left, middle notes in the middle, and high treble notes on the right.

The piano sound eminates off the top of the dampers where the hammers strike the strings. The audience sits perpendicular to the piano. They think they are hearing the true piano sound because the lid is raised, but they are actually hearing MONORAL sounding piano, because all the hammers are lined up at a point perpendicular to the audience. This is like placing the speakers of your stereo sound system one behind the other, which yields no stereo, due to lack of separation.

For the audience to accurately hear the true STEREO piano sound, they should be sitting behind the pianist, at which point they would hear low notes on the left, middle notes in the middle, and high notes on the right. Likewise, microphones should be placed accordingly on the left and right side of the piano, 12" above the strings to capture the true STEREO piano sound. And, the hinge of the piano lid should not be on the left side of the piano, but rather on the curved end of the piano, with two prop sticks holding it up on the right and left sides.

It would look weird to see the pianist with his/her back to the audience, but the piano sound would be far better. Even so, concerts are equally about what people see as much as they hear, so nothing is going to change, since audiences need to see the pianist. However, in a recording studio, these principles can be used to accurately record the piano.

[Thesharkz]

Two from the vault had that same problem but they soveld that issue.

[matako]

Once you've recorded -with, lets say, 8 mics (2 kik mics, 2 snare top & bottom, hihat, toms) how do you check for the mics that are cancelling ...
How do you compare the wave forms and know which one to adjust??

In other words...how do you know Which Mics are cancelling?

[timbordasch]

I still dont get it, how it works.
When i have a saw and a sin wave, then there will be also phase cancellation in a way right?
So why does our music, when we create it doesnt sound maximum shitty because all our different sounds (synths, acustic guitars etc.) are cancelling each other out in some ways?
They are all going to be outputted through the master, and before that they must cancelling each other out a little bit.

[thesonicexperience]

I've never heard of the 3 to 1 principle, and can't find any other info on it.. can anyone help me out with this?  I don't get it, because when you mic a drum kit, obviously your overheads and room mics are much further than 3 times the distance from the snare, than your snare drum close mic is.  So what gives with this 3 to 1 thing?

[CaretakersBand]

Good guide but not sure I fully understand. Why can you not correct phase cancellation by slightly adjusting one of the recordings a few ms earlier or later?

[alextremodelnorte]

Amazing information. May it be used for the benefit of the White race.

[MrMockigton]

and then there was this swede who put two sm57 mics at 45° angle to purposely filter frequencies : ^)

[tammytomita]

Check out my recordings and let me now what you guys think🙂😎

[NMTCG]

"one of the sure way for things to sound bad is a result of a phenomenon known as phase cancellation" I am out of here. Phase cancellation can make your recording sounds better, just use your ears and don't listen this tutorial - even absolute phase cancellation would result in totla silence, which is not "sound bad" anyway