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#962447 - 06/05/01 02:40 AM How do you flip the phase?
KikkyMonk Offline
Senior Member

Registered: 04/03/01
Posts: 447
Loc: Vista,CA,UNITED STATES
Can you use cakewalk to "Try flipping the phase of one channel of a stereo recording, summing both channels to mono, and then listening to all of the parts which aren't panned dead center in the mix. You can hear the kinds of reverb being used, predelay on the reverb, compression, etc." ?

If you cant use cakewalk what programs can you use?

Dave

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#962448 - 06/05/01 02:58 AM Re: How do you flip the phase?
KikkyMonk Offline
Senior Member

Registered: 04/03/01
Posts: 447
Loc: Vista,CA,UNITED STATES
Alright... i downloaded sonic foundry demo version. I think I did it... I went to channel converter and made one all left and one all right then inverted one... I think i got what i was looking for except there is alot of audio pops and scratches... how do you avoid this?

dave

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#962449 - 06/05/01 03:16 AM Re: How do you flip the phase?
Anderton Offline
MP Hall of Fame Member

Registered: 01/28/00
Posts: 7377
Sonar has a phase flip switch on each channel. It looks like an O with a slash through it. If you clone an audio track and flip the phase of one of them, the sound disappears.
_________________________
Craig Anderton
*check out my podcast at www.cyberears.com

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#962450 - 06/05/01 10:15 AM Re: How do you flip the phase?
- Offline
Platinum Member

Registered: 03/13/01
Posts: 1999
Quote:
Originally posted by KikkyMonk:
Alright... i downloaded sonic foundry demo version. I think I did it... I went to channel converter and made one all left and one all right then inverted one... I think i got what i was looking for except there is alot of audio pops and scratches... how do you avoid this?

dave


I don't know if this is the problem or not, but are you taking a file which used to be a mp3 and trying this? If so, you'll see just how much info is thrown away for the left/right channels with mp3s (a lot!). Oftentimes, all you'll be left with is what sounds like underwater gurgling (part of the mp3 compression) and random pops which were part of the original CD ripping.

Or are you maybe using a file which was originally from a record...? Or perhaps a badly-ripped WAV file from CD?

Something else to consider... I've found this trick to be *really* educational with certain mixes, and not very informative at all with others. So if you don't get something which sounds pretty drastic, try another song until you get one which really opens up your ears... Generally, I've had the best luck with mixes which are very dense with a lot of overdubs. Good luck!


This message has been edited by popmusic on 06-05-2001 at 07:33 AM

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#962451 - 06/05/01 02:03 PM Re: How do you flip the phase?
Ethan Winer Offline
MP Hall of Fame Member

Registered: 06/12/00
Posts: 8905
Loc: New Milford, CT, USA
Dave,

> If you cant use cakewalk what programs can you use? <

I wrote an article that explains how to do this with SoundForge. The point of the article was to show how to reduce vocals in a complete mix, but the technique can be used for other purposes too. Go to my Magazine Articles page:


http://www.ethanwiner.com/articles.html

And look for "The Truth About Vocal Eliminators."

--Ethan

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#962452 - 06/05/01 07:16 PM Re: How do you flip the phase?
Notape_dup1 Offline
Member

Registered: 07/25/01
Posts: 5
Loc: ,,UNITED STATES
Quote:
Originally posted by KikkyMonk:
Alright... i downloaded sonic foundry demo version. I think I did it... I went to channel converter and made one all left and one all right then inverted one... I think i got what i was looking for except there is alot of audio pops and scratches... how do you avoid this?

dave


I'm assuming this is 'sound forge' you're talking about. In addition to the channel converter, there is also an 'invert/flip' function which knocks the signal 180 degrees out of phase. I use the invert/flip to reverse the phase on one channel and leave the other channel alone. This sort of thing is useful if you are going into a mixer, and both channels are panned to the center. Idealy, if both channels are mixed equaly, you get the same effect, and going into a mixer allows you to 'fine tune' the common mode rejection. There is also a way to do this without software, I have a small peice of patch cable (6") with a male XLR on one end and a female XLR on the other end. On one end, I reversed pins 2 and 3 which reverses the phase of the signal traveling through the cable (extremely useful, every studio should have a few of these laying around). The same can be done with 1/4", just reverse tip and ring. I hope you found some info here you could use.

Good luck,
-notape

This message has been edited by notape on 06-05-2001 at 07:26 PM

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#962453 - 12/28/01 01:11 AM Re: How do you flip the phase?
KikkyMonk Offline
Senior Member

Registered: 04/03/01
Posts: 447
Loc: Vista,CA,UNITED STATES
Alrighty

Some time ago I started this thread, now I need some more help. I got the everything that isn't dead center to work but now I would like to have only the things that are dead center (bass vocals drums) which would be the opposite of what I was asking in this thread. I tried to figger it out but my noggin hurts

Thanks
Dave

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#962454 - 12/28/01 02:38 AM Re: How do you flip the phase?
- Offline
Platinum Member

Registered: 03/13/01
Posts: 1999
Here's one way to do it...

Take the mono "stuff that's not in both ears" file that you created earlier, flip the phase of *that* file, then turn it into a stereo file with two channels (the same signal is on both channels).

Now combine that "stuff that's not in both ears" file with the original stereo recording. What should happen is that all of the centrally panned stuff will be remaining.

I haven't found these kinds of mixes to be nearly as educational as the ones where you can hear stuff that's not in both ears, as... Well, all of these instruments are centrally panned and they're the ones the listener focuses on anyway. It's kinda neat to hear the mix with some of the other instruments gone, though.

Hope this helps!

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#962455 - 12/28/01 05:22 AM Re: How do you flip the phase?
Anderton Offline
MP Hall of Fame Member

Registered: 01/28/00
Posts: 7377
Hey Popmusic, VERY clever!! I'm going to have to try that one of these days.
_________________________
Craig Anderton
*check out my podcast at www.cyberears.com

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#962456 - 12/28/01 10:14 AM Re: How do you flip the phase?
- Offline
Platinum Member

Registered: 03/13/01
Posts: 1999
Quote:
Originally posted by Anderton:
Hey Popmusic, VERY clever!! I'm going to have to try that one of these days.


Thanks, Craig! I actually have a number of CDs I've burned that are phase-reversed versions of albums where I really dig the production.

They're kinda odd to listen to at first, but it's great when you're working on your own productions because it's nice to have a mental reference how your favorite albums were produced. Likewise, listening to stuff this way has really helped me with -- I don't know the technical term for it, but I call it "dovetailing" (how instruments in an arrangement play off of each other and complement the melody). It's like all of the subtle things in a production are suddenly front and center.

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#962457 - 12/28/01 04:30 PM Re: How do you flip the phase?
KikkyMonk Offline
Senior Member

Registered: 04/03/01
Posts: 447
Loc: Vista,CA,UNITED STATES
Yeah Ive found it super useful for picking apart huge layered peices as it helps by removing some of the thickness. Its great fun!

Dave

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#962458 - 12/28/01 05:05 PM Re: How do you flip the phase?
garyd Offline
Senior Member

Registered: 04/26/01
Posts: 69
Loc: CA,UNITED STATES
Quote:
Originally posted by popmusic:
Here's one way to do it...

Take the mono "stuff that's not in both ears" file that you created earlier, flip the phase of *that* file, then turn it into a stereo file with two channels (the same signal is on both channels).

Now combine that "stuff that's not in both ears" file with the original stereo recording. What should happen is that all of the centrally panned stuff will be remaining.

Hope this helps!


OK, I admit I'm dense, but I can't see how this could possibly eliminate everything except the center-panned stuff.

Look at it this way - what you have after the elimination of the "stuff in the center" is really this: -L + R (or it's inverse).

Adding this signal to the L and R signals yields, respectively:

L + (-L + R) and R + (-L + R )

which simplifies to:

R and -L + 2R

It doesn't matter if you invert the polarity, you'd just get the inverse of the above.

The problem remains that you still have the L and R information, no matter how you invert and add.

What am I missing here?
-Gary
_________________________
-Gary

http://www.soundclick.com/bands/8/garydmusic.htm

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#962459 - 12/28/01 05:16 PM Re: How do you flip the phase?
- Offline
Platinum Member

Registered: 03/13/01
Posts: 1999
I may have been mistaken -- let me think through this... I know I was able to do this once... What if you did it this way:

INVERTED_TRACK_A = ORIGINAL_TRACK_LEFT (phase inverted) + ORIGINAL_TRACK_RIGHT

INVERTED_TRACK_B = ORIGINAL_TRACK_LEFT + ORIGINAL_TRACK_RIGHT (phase inverted)

So you have two tracks which have eliminated all of the sound that's panned in the center. Then you combine them like this:

NEW_CENTER_STEREO_LEFT = ORIGINAL_TRACK_LEFT + INVERTED_TRACK_B (phase inverted)

NEW_CENTER_STEREO_RIGHT = ORIGINAL_TRACK_RIGHT + INVERTED_TRACK_A (phase inverted)

I'm not sure if this is right either... Let me see if I can dig up an old post I made on George's forum where I described what I did to get the stuff panned centrally... I know I got this to work before. \:\)

[ 12-28-2001: Message edited by: popmusic ]

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#962460 - 12/28/01 05:56 PM Re: How do you flip the phase?
- Offline
Platinum Member

Registered: 03/13/01
Posts: 1999
I dug up the old post, and it wasn't specific.

I'm pretty sure I did what I mentioned on my previous post.

INVERTED_TRACK_A would be everything that's not in the center of the mix, but with the right channel phase being the same as the original.

INVERTED_TRACK_B would also be everything that's not in the center of the mix, but with the left channel phase being the same as the original.

So if you combined ORIGINAL_TRACK_LEFT with the inverted phase version of INVERTED_TRACK_B, that would effectively take out everything that was panned hard left. Likewise, if you combined ORIGINAL_TRACK_RIGHT with the inverted phase version of INVERTED_TRACK_A, that would take out everything panned hard right.

So, to correct myself -- no, you won't take out everything except for what's in the center of the mix. Instead you would take out basically the far reaches of the left and right channels, which can still be somewhat interesting, but still not as educational as simply phase reversing one channel and combining it with the other in mono.

Thanks for picking up on that!

[ 12-28-2001: Message edited by: popmusic ]

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