Thanks Bruce, course read interesting so far.

Phase 1)I'm wondering what tools do you, or other folks know of that can help us correct phase issues?

Phase 2) Are there any things to look out for apart from playing tracks individually and looking at monitors movement and then playing two tracks together ?

Phase 3) Could we see this on spectral analysis type tools eg VoxengoSPAN, Curve EQ or others ?

Phase 4) Could Sonic maximisers eg BBE exgerate or reduce the phase cancellation occuring ?

Phase 5) Can phase problems occur with software based instruments (my logic says yes...but one can be wrong)?

Phase 6) Can phase problems contribute to muddy a mix? Yes I'm certain of this from your notes. but please correct if I'm talking nonsesne

Sorry there is a whole bunch of loose Q's there....I love the articles, and now am trying to think how to apply, fix, spot and correct if found. eg re the drums and the overheads.

Maybe you go through/ or some of the folks on the course mentioned go through a repetitive routine that identify and corrects phase, that may be worth sharing more detail on.

This is open to anyone on the course to contribute thoughts too !

Many thanks

Most mic pre's have a "phase" switch that will reverse the polarity of the sound.

Although it is possible to hear the difference between a sound that is pushing a speaker out rather than sucking a speaker in, it is in the blending of at least TWO sounds that phase issues become more obvious.

Phase meters will show the phase strength, so they can be handy.

The BBE (nice for strings and ac gtrs) is a "time alignment" device, so I am sure it is messing with phase in parts of the sound....I will try to find out more about that in particular.

Phase can be introduced at various stages. Putting a plugin on a track will introduce a TINY delay that can push the track out of phase...maybe not 180 degrees, but certainly enough to lose bottom.

Phase will thin things out through subtraction, which is a different issue from muddiness.

A good way to deal with phase is to just very carefully make sure that anything you are combining sounds strong...you may need to push that phase switch (which will change sounds 180 degrees) or even (gasp) MOVE a mic so that the sound reaches it after a different DELAY as it moves through the air.

REMEMBER TO MAKE SURE YOUR SPEAKERS, AMP AND EVERYTHING ELSE IS IN PHASE AND THE CORRECT POLARITY.

I am finishing some quick notes about monitoring that I will post soon...I think that will help you.

OK...now here is something to really screw you up...sometimes I have intentionally introduced out of phase components in order to create more width in a mix, but I had to check mono compatibility! (much much more about that later in the course).

Thanks for the questions...they not only help others but also help me to organize my thoughts for the course!

Bruce A Miller
http://BruceAMiller.us

Wow,

Thanks Bruce, quick response.

Will have to check Mic's etc for polarity.
I'll look for switches... any particular data I should be looking for in manuals.

And no laughing and hinting at the word PHASE ! ha ha ...i'll try that first though.

Thanks for clearing up the difference between muddy and thin sounding and my understanding of causes...will have to listen carefully at some effected sounds to practice spotting problems.

The PHA-979 below appears to give control over adjusting phase by different amounts, see what you think of the blurb in relation to this discussion. It is software, but the page gives some information in relation to time and degrees relation of "phase".

I thought I would post the link for people to maybe get benefit from reading the description.
Hopefully real example of things help all develop understanding better too.

http://www.voxengo.com/product/pha979/

If anyone has other stuff on this topic that would be great too

I can't wait for the next installment

Thanks Bruce

quote:

Will have to check Mic's etc for polarity.
I'll look for switches... any particular data I should be looking for in manuals.

a lot of times the switch will just have a picture of the greek letter Theta. This is like the number 0 but with a slash or dot through it...and it's sometimes italicized i think.

quote:

...sometimes I have intentionally introduced out of phase components in order to create more width in a mix, but I had to check mono compatibility!

Yes!! I've come across that before too! Sometimes on a stereo track I'll add a stereo delay with the two channels slightly off from eachother. Like set one delay to 6ms and the other to like 6.12ms. With some tracks it creates a wider image and carves a little out of the center. But, I thought maybe it was a secret only I figured out


While we're on the topic of phase/polarity...I found where in the article it talked about different wirings of different countries produces opposite polarity very interesting. Is this something we sould pay attention to a lot more? I know you said a lot of equipment is coming from the same countries now-a-days, but when mixing and matching gear and speakers maybe we should find out which way our speakers push?? Especially if we play an American CD one time and a European CD another.

Excellent question. I do not worry too much about mixing for a particular country's polarity. I just go for overall warmth and bottom...but like I said I have noticed differences with stuff mixed there being heard here without flipping the polarity.

I am ASSUMING (very dangerous thing to do) that consumers are listening to stereo systems with the polarity of the manufacturer's country. If that is the case, then the more Sony boom boxes sold, the more people are listening to the US/Japanese polarity.

So this problem of unstandardized polarity may be working itself out anyway.

BUT if you are recording with audio gear from different countries (the Neves are from England, the board is from your Uncle, whatever)just remember to check phase between any sound sources that are being combined by flipping that phase switch and listening.

-B

I think more research on this is a good idea....although I will not have the time to do so in a while (I have much to mix, write and post first!)

If anyone wants to research this issue (polarity, countries and what consumers hear) I will post the research results in the audio course...with proper credits!

-B

I'm familiar with the concept of phase angles, 180 out gets cancellation, in phase "can" give you a gain effect but how to know if or what to do when say phase angles are more like 90 or do we care. Some gear will get you phase reversal options but dealing with several mics which aren't quite 180 out from one another it seems the only thing is to take physical measurments from the sound source and move the mics. I imagine a situation where you have several mics set up...the more mics even only slightly out of phase I would think would muddy up the audio.

Is this something to consider or am I over analyzing the situation?

YES, less is more when it comes to mics. If I put up more than a stereo pair on anything then I had BETTER be getting something important from the extra mic(s) to make the phase incoherencies worthwhile.

Drum overhead mic height is important (even if you are using your overheads as cymbal mics with all the lows cut). Try to record a little, then move the overheads up or down an inch or so, then record a little more...then listen and go back to what you feel sounds the fullest (or more accurately, what screws up the phase the least). Don't forget to flip phase on occasion and listen. I tend to have my overhead mics in a spot that puts them OUT of phase with the K & SN mics, so I always need to hit that phase switch to hear the real bottom.

While the 1:3 rule is important (if the first mic is 1 foot away the next mic should be 3 feet away), I have never seen anyone pull out a tape measure on a session. Add the fact that musicians move when they play and it gets more complicated (ac bass, ac gtr, VOCALS, etc).

So yes, it is something to consider and no, you are not over analyzing.

You know, just a week ago, I was listening to Radiohead, wondering why do their recordings sound different? Why does Hail to the Theif (recorded in LA) sound different from Kid A (recorded somewhere in England)? Then an hour ago I read about the Polarity issue. I already knew that they like to pan everything to extremes and that they use some weird techniques, but even their "normal" stuff sounds just a little different.

all i can say is....hmmmmmm........

Thanks

Hey Bruce, carrying your train of thought a little further about the delay caused by plugins. Generally the first thing I do is go and phase align all my drum tracks by zooming in and lining up the peaks and valleys, then listening back to make sure I'm getting a good sound. At that point I'll add some gating/compression to some of the individual tracks and some EQ. I try to make sure I have the little box checked for delay compensation in the plugs, but is there anyway to ensure that you're not delaying the signal to start getting some cancellation? My problem is that when I try to listen to the difference by bypassing the compressor/gate or EQ, it's hard for me to really tell if the difference is from cancellation coming from delay or if it's just the plugin itself. Follow?

quote:

Originally posted by bennychico11:

quote:

Will have to check Mic's etc for polarity.
I'll look for switches... any particular data I should be looking for in manuals.

a lot of times the switch will just have a picture of the greek letter Theta. This is like the number 0 but with a slash or dot through it...and it's sometimes italicized i think.

It's actually the Greek letter Phi. When writing Phi, the oval is almost (if not completely) circular and the slash is almost vertical (leans slightly right) and passes through both sides of the oval. Theta is more oblong and the slash is horizontal and stays within the oval.

Sorry...math/engineering background :-) Just a fun fact, I don't mean to step on your toes.

Mix engineer Jeff Wolpert gave a guest lecture for my class, and suggested that using a DAW to nudge the drum tracks into phase with each other can help bring a recording into focus. He said that sometimes it's enough to nudge the snare into phase with the overheads.

The thought is that, since the snare drum is four or six feet away from the overhead mics, that the recording of the snare in the overhead mics will be four to six milliseconds behind the snare in the snare mic, and aligning them helps the snare to "pop". (The numbers here are broad estimations.)

Since it seemed that Jeff had some a little background , I tried it on a number of class projects. For some, it seemed to me to be a great success, and for others less so. A little bit due to the skill of the recording engineer, and a little luck of the draw perhaps. My favourite result with this trick so far was with a live off* the floor recording of an improvisational band which we did with about 22 mics in total. By aligning the drummer's count in as tightly as I could across all the tracks, it seemed to me that the instruments were more lively and easier to balance.

If you mix 'in the box' you might check out TritoneDigital's 'PhaseTone - it's free. It has 3 phase settings for each channel as well as frequency and mixture sliders. There are also delay settings.

The differences can be remarkable and it's a cheap and useful little software gadget.

quote:

The differences can be remarkable and it's a cheap and useful little software gadget.

I'll say - it's free! Thanks for the link, even though it DID cost me a night of sleep. This moves to the keeper section of my toolbox. I also downloaded the free version of TriTone's ColorTone and found some lovely results with it.

I'd not heard of TriTone before - thanks for the "heads up", Bruce.

And a link, for those intrigued: http://www.tritonedigital.com/products.htm

About a year ago, phase became one of the most annoying "features" of the various boards that I own: they had no phase switches. I ended up hunting down a board I could afford that had phase flip switches. Its not really a big deal because its easy to do in software, but... I'd rather knock out those problems when tracking and use my limited CPU processing for fun stuff. And it takes WAY less time than aligning the tracks in the computer. Just because I can edit doesn't mean I want to!

In Pro Tools most of the Digidesign plugs have a phase flip button. Its just the Phi (or Theta) symbol and usually isn't labeled. Doesn't take much CPU if you use a low impact plug (I use "gain") and leave it set to unity.

I think the Cubase SX mixer has phase flip built in somewhere, but I don't use it enough to remember where.

Take care,
Chris

I've used Beat Detective to fine-align tracks in ProTools, but it only works if there is information on all concerned tracks in common - like snare hits. Sometimes that's more trouble than it's worth, tho, and if it doesn't click the first time I don't bother. But if all the tracks start with the same impulses (such as the drummer's count in), I can tab to the transient, set sync point, and then CTRL-Click the rest in sync and that goes quickly. This is more of an effect than to solve serious phasing issues, and not always an effective ... erm ... effect. But I've experimented with it often enough that I can sync up the drums in about five minutes, and the benefit is that it works as well for all degrees of phase as well as flopping works for 180.

As you say, circumventing phase issues during tracking is much better than squinting at the DAW to do it. I find that if I get distracted over tweaking these pesky details, I can lose "sight" of the sound.