You need to be able to reverse the phase of one of the mics. This may be done by a couple of means:
If your DAW software permits you to "flip" the phase of 1 of the tracks, do that.
You can wire a mic cable so that the "+" and "-" pins at one of the ends are reversed from the same at the other end.
And, alternatively, you can purchase a polarity reversing adapter (Shure and A-T, as well as some others). This is a metal tube with XLR's at each end. The XLRs are wired out of phase, making this a snap at the time of the tracking.

Do you think this will result in loss of signal and/or frequency cancellation though because the mics are so similar?

Nope. Nada. Aint gonna happen.

Its two mics. Similar specs.Still different. Different placement(even an inch matters) Two separate tracks. With the phase relationship in control you can fashion whatever you want from this setup. Is it ideal? Maybe.

Heres where you discover the wonders of individual mics' abilities to reproduce frequencies. You may find that the positions of these two mics need to be exactly the opposite of what you start with.

There is no 'go to' formula. Its what it is for each situation and for each track if you want to get down to the true nitty-gritty.

You could simply throw em up and push the red button. Or you can agonize endlessly over minute positioning to get that perfect noise you seek.

Thats the fun part of all of this.

Any way you get it is going to be correct if its waht you want to represent your sound with. If it doesnt sound like you want it to,then you need to continue with the experiment until it does.

Thanks Sir Dog. As long as you think I won't have any problems then it should be cool I guess. I just remember that one time that I used them both and had problems when I tried to EQ the tracks, where the result was boomy and ruined the entire capture. My ears aren't that developed yet to 'hear' phase issues or other problems when mixing these tracks together other than that one time where it was glaringly obvious, so I'll have to rely on your word for now.

Is there any help you can offer me to help develop my ear to detect these things when they do occur? Such as phase problems or anything else to watch out for?

Even if you can't hear the phase problems, you may be able to see them. And once you can see them you may be able to teach yourself to hear them. Take the two tracks and blow them up both vertically and horizontally until you can clearly see the peaks and valleys of the wave form - say .25 sec. or less filling up the width of the screen. The waveforms will be different since they are different mics in different positions - but they will be similar. The biggest difference is that the waveform of the i5 will be delayed - the sound will reach it after the 57. I don't know what DAW you are using, but I assume you can grab the i5 track and move it slightly to the left so that it lines up better with the 57 track. You want the most prominent peaks and valleys to occur at the same time. That should give you a strong clear sound. Now try to get the worst sound possible. move one of the tracks so that the peaks align with the valleys and vice versa. Pan everything to center. The sound should be pretty awful. That's phase cancellation.

Ahh, that's brilliant! I never thought to adjust their place in time but it does sound more powerful now with a clearer attack :D Good stuff 8-)

BTW, I am on Logic Express.

Wait a second...

I'm really confuzzeled here.

GF... You're giving gear and mixing advice to newbs in the pro audio forums, and you don't know how to mic a cab with multiple mic's, do phase/time alignment, or set up comps, gates, delays or verbs?

OK, this splain's a lot...

What Bob said is dead on. If you can't hear it, and a lot of plank spanker's I know are about deaf as a post in the 3-5k range, then watch the wave forms.

Another "trick" is to actually learn your rig. This is tedious as hell, but worth every second you put into it.

Create a new song... but just one. Name it Speaker 1. This is extremely important!

Take one mic or the other and place it dead center in front on one speaker in the cab. Place the mic 1" from the grill. Track it playing a short (30-60 sec) piece of music you can't help but play the same every time you put a plank in your hands.

Move the mic vertically up by the diameter of the diaphragm, or 1" - whichever is less. Track it playing the same friggin' piece, but adding on to the song as a new region on the timeline... like a verse.

Move the mic vert again, 1 mic diameter... lather, rinse repeat... again and again and again... until you reach the edge of the speaker, then go back to the center and go downward... then left, then right.

Save the song without processing, EQ, or anything else.

Now create another song and name it speaker 2. Go to your 2nd speaker (if applicable) and do the whole tedious process again.

Do this with every speaker in the cabinet.

Save all these "songs" to a folder named for your mic you were using.

Repeat the entire painful process with your other mic.

Now, if you survive the whole thing without shooting yourself, you can load the "songs" in an itoonz play list that makes some sense.... like, speaker 1, speaker 2, etc.

Make the speaker 1 playlist; speaker 1/57 and speaker 1/i5.

Listen carefully, you'll likely find out that there is a speaker that generally sounds "better" with each mic. At least you can note what characteristics are what, with each position.... phat, thin, tinny, boxy, etc.

Now you can probably guess which combination of which mic, in front of which speaker is going to get you closer to the sound you want, without having to continually guess wtf you should do.

If you're really a massochist at heart, and most of you planker's are from what I can tell, you can then try a rehash of this insane experiment, by trying each mic at different distances from the speaker... moving the mic back away from the speaker by 1".

The key here is to make yourself some detailed notes, and be sure you make notations on each take, in the regions' timeline or on the region itself. That way you can better identify what setting you want to use.

A lot of touring pro's do this whole insane process and will actually mark the grill with an "L" of tape where they prefer the FOH AE to put the mic. That way, their sound is consistent.

MadMax wrote: GF... You're giving gear and mixing advice to newbs in the pro audio forums, and you don't know how to mic a cab with multiple mic's, do phase/time alignment, or set up comps, gates, delays or verbs?

Haha. Well I never said I didn't know how to set up comps gates delays or verbs. The only thing was understanding the phase thing when doing combo close/far miking. I was confused as to why there is a few different laws regarding how to track to not introduce phase problems. But I think what Bob said made it click. It doesn't really matter at what distance you mic because as long as you shift to allow for the difference in latency for the time it takes the sound to travel to the second mic (and then do a phase flip?) then you should be fine.

And just in defense of myself, I like to help the super noobs and point them in the right direction so I can save the pro's the time of explaining so that they can focus on bigger problems. I never said the advice I offer is pro :shock: Plus I'd like to believe that from monitoring the threads you guys write on that I have at least a decent understanding of even some of the more complicated principles floating around here, even if I have no experience with it.

Anywho... that really is a neat trick and I might have to do it one of these days if I get an empty house for any length of time. Thanks Max 8-)

time aligning by sliding tracks can help in some cases, and in others it can kill the room vibe. Use your artistic judgement, but by all means play with it.

I'm bouncing a few MP3's to my iPod right now so that I can A/B them and see what my efforts have created and as to what sounds good. Just in case you were wondering, there are three files in question from a project that was miked in the previously described way. This is what I am going to listen to now.

1. Dry tracks (not time corrected)
2. Dry tracks (time corrected)
3. Dry tracks (time corrected + i5 phase flip)

If you'd like to hear them let me know.

Whether or not you want to hear them here they are 8)

http://soundclick.com/share?songid=7765908
http://soundclick.com/share?songid=7862345
http://soundclick.com/share?songid=7862347

Okay. when you listen, what do you hear? I hear one track that is close, one that is blatantly out of phase presenting hollow sound and one that has large frequency cancellation.

You could simply throw em up and push the red button.

Guilty as charged. But experimentation is key in getting the sound that you like. Just because so-and-so says to do things ____ way doesn't mean you have to.

And about phase issues... Some people intentionally disalign peaks to yield a thicker sound. Phasing guitars just don't bother me that much I guess. And what about Randy Rhoads? Talk about out of phase... But what really bugs me is pitch shifting sharp -- that is unbelievably grating to my ears, but some people don't even notice it, or some people won't notice even if one of the tracks is pitch shifted ridiculously flat. Maybe it's the same way with phasing issues?

hueseph wrote: Okay. when you listen, what do you hear? I hear one track that is close, one that is blatantly out of phase presenting hollow sound and one that has large frequency cancellation.

See, like I said, without monitors or experience with this stuff all I hear is three different sounding guitar tracks.

The first one sounds airy and not even that distorted. The palm mutes sound weak and there's little note definition.

The second one is more defined and has better pick attacks.

The third sounds completely different from the other two but I'm trying to decide if that's a good thing or a bad thing.

To me the third sounds more like a guitar, but it sounds like it takes up less space in the mix. Because of frequency cancellation? But who is to say that the original tracks weren't taking up TOO much excessive space because THOSE are the problem tracks. It's been a long time since I tracked this so trying to remember which track sounded more like my amp that day is out of the question.

Throw me a bone here, this isn't exactly high school geometry. Phase relationships are not the kind of thing that just makes sense right off the bat. You have to experience the ins and outs, the good and bad.

See, like I said, without monitors or experience with this stuff all I hear is three different sounding guitar tracks.

The first one sounds airy and not even that distorted. The palm mutes sound weak and there's little note definition.

The second one is more defined and has better pick attacks.

The third sounds completely different from the other two but I'm trying to decide if that's a good thing or a bad thing.

To me the third sounds more like a guitar, but it sounds like it takes up less space in the mix. Because of frequency cancellation? But who is to say that the original tracks weren't taking up TOO much excessive space because THOSE are the problem tracks. It's been a long time since I tracked this so trying to remember which track sounded more like my amp that day is out of the question. Throw me a bone here, this isn't exactly high school geometry. Phase relationships are not the kind of thing that just makes sense right off the bat. You have to experience the ins and outs, the good and bad.

Have you ever heard a flanger before? Phasing sounds similar to that. If you can't hear phasing when it's severe, well, you must be partially deaf or something, haha.

NCdan wrote: Have you ever heard a flanger before? Phasing sounds similar to that. If you can't hear phasing when it's severe, well, you must be partially deaf or something, haha.

No, that can't be accurate. If you click in a wah pedal and leave it at one setting, you cannot describe the resulting sound as being a 'wah' sound. It is then just a different sounding guitar track.

No, that can't be accurate. If you click in a wah pedal and leave it at one setting, you cannot describe the resulting sound as being a 'wah' sound. It is then just a different sounding guitar track.

Out of phase tracks aren't static: they fluctuate. You should be able to hear the track going EEeeooooOOOOHHHHHeeeEEEEooooWWWW... or something like that, anyway.

The first one is blatantly out of phase. The second is very close if not as good as you can do with the take. The third has a lot of frequency cancellation because you were already close with the time shifting but when you reversed the phase of one channel threw it completely 180 degrees out of phase.

There's no doubt that they all sound very different, even I can hear that. I just don't know what 'out of phase' sounds like. They are obviously only partially out of phase because if they were completely out of phase there would be no signal. I get that

If you had never seen or heard of a cat before, and somebody showed you three animals you had also never seen before, do you think you would be able to choose which was a cat? I just don't know which track is the 'glaringly obvious out of phase track' because I have no idea what obviously out of phase tracks sound like.

Thanks Hueseph. If you are right about the dry tracks being very out of phase, I guess that blows to shit the 3:1 phase relationship thing because I actually pulled out a tape measure to make sure that it was exactly 3:1 during tracking.

OK, so from re-reading Bob's post before because I found it very helpful... does the out of phaseness come from the tracks not being lined up in time properly? So instead of saying they are out of phase, isn't it more accurate to say that they are out of time? And if this is so, then wtf is the polarity flipper even there for if all you have to do is align them? People often refer to the polarity flip as being a 'phase flip'.

This is where I think my misunderstanding comes from, is that there seems to be more than one definition to the word phase and they don't line up... they're out of phase

lml 8) lml

Guitarfreak wrote: Thanks Hueseph. If you are right about the dry tracks being very out of phase, I guess that blows to shit the 3:1 phase relationship thing because I actually pulled out a tape measure to make sure that it was exactly 3:1 during tracking.

To iterate: 3:1 ratio applies when you are using a spaced pair only. The distance between the mics should be three times the distance to the source. If you are using one close mic and one distant, this does not apply.

If you are using a spaced pair, you need only make a small adjustment to the mic. The 3:1 ratio gets you in the ballpark but also is intended to maintain a balanced stereo image. It does not guarantee perfect phase.

Phase is the relationship between signals. The difference between the time when each signal peak is picked up at the mic determines their "in-phaseness". That is why you can time shift them in your DAW to correct the phase.

hueseph wrote: Phase is the relationship between signals. The difference between the time when each signal peak is picked up at the mic determines their "in-phaseness". That is why you can time shift them in your DAW to correct the phase.

Ahh, this thread has been a very eye opening thread for sure.

So then if that is true, why would anyone ever want to flip the polarity? Because I thought you flipped the polarity when things were out off phase to put them correctly in phase. That seems to be the message people were telling me previously to this thread. Now the idea makes little to no actual sense.

Sometimes your mics already 180degrees out of phase. Flipping the switch can solve that. SOMETIMES.

Well if the polarity flip is an 'easy button' instead of doing the time correct, then I would much rather do the time correct.

Or are you saying that in certain circumstances the tracks are perfectly in time yet still out of phase?

The polarity button is also used in M/S decoding when you want to change which side of the figure of 8 is dominant (simplified explanation). Also, sometimes, and not all the time, it is desirable to put tracks purposefully out of phase for a designed effect. Long story short, the polarity button isn't an "easy" button in the sense that it fixes anything inre alignment of tracks. It's there to specifically flip an electric signal 180 degrees.

Didn't say you shouldn't help, nor meant to imply anyone shouldn't. It's just that sometimes some of your "pointing noobs in the right direction" just isn't quite cricket, and just points to a lack of experience... that's all.

Nothing wrong with helping folks... hell, that's what I'd hope the majority of the folks around here would do.

We all help with what we can.

Sometimes we're right, sometimes we're wrong, and sometimes we're in between. I just noticed that a lot of your posts are what I would call; in between.

But, yep... it's a tedious process I outlined, but one you would get a lot of benefit from... especially when you combine the two mic's... which thankfully to digital technology, you can actually copy parts from two songs, (e.g. two speakers, using two different mic's) and create a 3rd bit of knowledge from.

[edit]
What is Phase?... http://www.indiana.edu/~emusic/acoustics/phase.htm

Simple answer is always a nother question: does it work in the mix?
To me every element of the mix should 'play nicely' with the other elements. Does a little phasing on the guitar help it create its own space in the mix?
Or its does cause the guitar to blend into the background?

Understanding the basics of phase can help you make repeatable and consistant recordings. But all rules were meant to broken.

The only rule there is... is there are no rules.

As has been said, your first track is really out of phase. Its not anywhere close to 180 degrees so it has that standing 'honk' tone much like a wah pedal half down. Or part of the sweep of a flanger as was suggested.

The second track is relatively free of anomilies associated with phase problems. Even on this laptops speakers I can hear the frequencies are mostly all there and your micing is capturing something close to what your amp is reproducing.

The third one is something past either of the others. Theres the 'wonk' again but it sounds different, probably because the relationship of the two mics is different. They are out of phase but the other mic is now the dominant one as opposed to the first clip.

These are essential parts of a knowledge level that you need to study. The wiki will get you to things that will open your mind.

Grasping these essentials is important to your growth. Both your mind and your ear will have an easier time translating what is happening in your room. On your gear. Enthusiastic help is wonderful. Enthusiastic help without knowledge is dangerous. As long as you are willing to be corrected on things that have a basis in truth with proven experience then you'll do well. Supposition and heresay about things are the bane of the information hiway. We try and keep this stuff to a minimum here.

And yes, it IS Junior Hi-school Geometry.

At that point you will be somewhat more qualified to be a better help to those totally clueless.

This is recording 101. My name is Professor Dogg and there will a quiz at the end of the class.

Now thank all the kind Doctural level folks who have helped you.

PS. I wanted to add something that was touched on. Theres nothing in the rule book that says a little out-of-phase is harmfull to you recordings.

Sometimes it helps cut through a dense mix of a lot of the same notes.

The Rule Book only has referrence to the actual physics of sound being transmitted in a given space and the action of a device to capture this sound and its devices used to contain this capture in real time.

How you get there is up to you.

Thanks Professor Dog, always a great help. To tell the truth, I had never liked the sound I had gotten with the original capture, but now thanks to everyone here I now know why. It's crazy that there is no meter for this kind of thing, and no way of knowing that it is going on... unless of course you know that it is going on.

A few wrap up questions:

1. So it really doesn't matter WHERE in the room you put the distant mic when using the close/far technique, so long as it sounds good and is in phase?

2. Is there a plug or a meter that shows whether two inputs are in phase or to what degree they are in/out? Because having to track something short then blow up and examine the waveforms to verify if your miking is good or bad is tedious and I'd have to imagine that there is another better way to do it.

A couple of points:

1. When you mic a single, localized source with two mics at different distances there will always be a time difference. When you mix these together on a single track, the delay (a phase difference) will reinforce some frequencies and cancel others. This is called comb filtering. (And yes, it is high school trigonometry.) You can eliminate the effect by time shifting. You can minimize the effect by using a smaller amount of one track than the other.

2. Because of what I said above I can't see any sense in using the 3:1 rule for two mics on a single source. I've seen this posted in "expert" resources on the web, but I think it is nonsense. The 3:1 rule makes perfect sense if you are mixing multiple mics on multiple sources into one track - say a horn section. In this case, every mic has its main source + the bleed from the other sources. The 3:1 rule ensures that the bleed is quiet enough that the phase problems with the main source in the other mics are minimal.

3. Other people have already said this, but I'll repeat. Please don't take what I've said to suggest that every track in a mix has to be phase aligned with all delays eliminated. The whole point of all the stereo recording techniques like AB, XY, ORTF, MS, ECT. is to use various delays to suggest a natural sound to our ears (which are, of course, two mics in different places).

4. If I really wanted to get all math professory and technical I'd say that inverting the polarity of a signal is not really a phase change. It only acts like it on pure sine waves and it shifts different frequencies by different amounts. But "phase" is used to mean a lot of slightly different things, so that's a really picky point. (I have to go back to grading vector calculus when I get done typing this, so I'll get the pickiness out of my system then.)

eliminate the effect by time shifting

Just to be a bit of a picky bugger....in the real world other reflections off the walls, floor and ceiling will affect the distant mic. These will not be the same in the close mic. So shifting the track in the time domain will not fix the phase shift in these reflections.

Link555 wrote:

eliminate the effect by time shifting

Just to be a bit of a picky bugger....in the real world other reflections off the walls, floor and ceiling will affect the distant mic. These will not be the same in the close mic. So shifting the track in the time domain will not fix the phase shift in these reflections.

How about "essentially eliminate?"

The point is to eliminate or at least control the comb filtering. Due to the fact that his room isnt treated, and the fact that he records loud and generally obnoxious music with lots of overtones, the contol of this in an uneffected room is going to be paramount to getting a good sound.

As ya'll perfesserz know, the frequencies most likely to be effected by nasty comb filtering are in the lowmids and upper mids...ie: guitar heaven.

While it is prudent to add a distant mic to give the listener a perception of size to the sound, it also introduces these anomolies that a close-mic'd setup will not necessarily have or at least wont be as prominant.

Especially if the distant mic is of the condenser style and has some serious sensitivity.

Heres a small secret.

Close mic the cabinet. Or combo amp. If its a cabinet, get the (*&^%$%#@ING HEAD off the cabinet. RIGHT NOW. Ask me why after you hear the difference.

Put your distant mic directly above the amp or the caninet. Move the distant mic around until you hear the tone really start to get thick and rich.
both mics playing.

STOP.

Play.

Record.

Now put a delay on the distant mic signal. Use a judicious amount of predelay on it.Reverse the delay as short as you can. NO DECAY.

Drink more Tequila.

Enjoy.

How about "essentially eliminate?"

8-) :lol:

Definitely will do DD. Hey about getting the two mics to sound good in the setting up phase (good lord there's that word again with yet another definition) I track in the same room that my amp is in. So hearing the subtle differences in mic position and mic blending is kind of tough. That's where I believe half of my problem with placement stems from and that's kind of why I asked if there was a plug that could help me "see" what was going on phase wise instead of relying on my ears with that confounded box yammering on a few feet behind me :D

Ooh, nvm that. THIS looks promising...

"not really.. i just check the polarity of every step of the signal chain, get the amp to sound cool in the room (which is by far the most difficult part and can be really painful sometimes as I can't really hear it with earplugs!), do BV's white noise check with headphones to find the sweet spot on the sweetest speaker, put the mic on it and then flip the phase and sweep the second mic around until it cancels out as much as possible. Then flip the phase back and it should sound massive!"

What do you think of that?

Have you thought of disconnecting all the speakers but one? Are you using a 4x12 or 2x12? Even if you are only using a 2x12 you will cut the volume quite a bit by disconnecting one of the speakers.