Howdy. Watching a mixing tut on Groove3 and the guy is talking about comparing the two overheads to the close mic'd kick for phase issues. It's confusing me a little as he hasn't actually shown an example of a phase problem. Just how he checks for one. I was under the impression phase was when your signals were too similar and canceled each other out making them quieter but I think after watching this that may be wrong. Just looking to find out what I should be looking for in the waveforms that would indicate a phase problem. He also mentions that nudging one clip slightly can fix it... I kind of knew that but have always just hit the phase button when I thought there was a problem (usually I would make this decision by listening to the tracks and if they were quiet and the phase button made them louder I'd leave the button on).

Sorry if that came out kind of garbled and thanks in advance for any insights.

Cheers.

I've watched both of Kenny Goia's Tracking Drum Tutes and as long as the peaks and valleys generally line up you are ok. But listen to what sounds best. From what I gather, you can be out of phase by 1 degree or 359. The phase switch flipped changes the phase by 180 degrees. At 90, the phase switch won't help and shifting the tracks to where the peaks align will help that situation. I'm sure someone else here knows more than I do and I will be checking up on this thread.

one way to check is to solo the track you are worried about, say the kick. start adding the other drum tracks and if you "lose" something, volume, punch, attack, etc., then phase could be your issue. it could also be frequency masking, which you can test for using (in this case) a high pass filter on suspect tracks.

the main thing for this and whatever other technical mix issues are coming up, is to answer these two questions:

what do i want the mix to sound like?

does it sound like that?

knowing what the problem could be is important, but knowing when you have a problem is essential. otherwise you could spend hours hunting down something that doesn't exist.

While you are adding close mikes tracks together you won't encounter many phase issues because the mikes are very close to the source and the next mike near it is much more than three times the distance away.

But with drums say for example it is when you mike the overheads from a little further away you can encounter some issues. Let us suppose you have miked up overheads and close miked all the other drum sounds. If you use mainly the close mikes for the drum sound and just add a hint of the overheads in for some quiet cymbal action then that is the drum sound you will hear and it will be a nice one but a close miked one. (you need more reverbs later though to put this close sound into a room again usually)

Let us say you used two rather larger diaphragm mikes for the OHeads and you want to create most of the drum sound by just using the overheads. And adding in a hint of the close mikes. Now this is a lovely easy way to achieve any decent drum sound. By just using overheads alone. Especially if the drums are nice and tuned and sound killer right there at the time (Sonor like mine!) and the player is consistent with all the surfaces they are hitting. (this is a skill, toms need to be hit harder, cymbals crashed and played way more quiet, hats very light touch too, snare and kick very consistent. Drummers have a lot of problems doing this! People like Steve Gadd are masters at playing every surface perfectly)

You will need to crank up the gain on playback from the overheads then in order to get most of the sound. This drum sound will be pretty stellar except it may be just lacking a little kick detail. So you decide to bring in the close miked kick as well into the picture. The overheads are going to have a lot of kick in them already and now you are bringing in the close mike kick and it is going to mix with the OHead kick either well or not so well. You will never know until you try it.

As soon as you do this the kick sound will either sound even more killer or the kick sound will start to go limp and lack bottom end, a little punch maybe and you will just think not good. This happens because the close kick mike is now adding certain things out of phase compared to the Oheads. But what you can do and I would do this before any time shifting of anything is to reverse the polarity of the close kick sound and what mostly happens is the kick sound now goes from the whimpy limp sound back to a ballsy punchy fat sound again. So you just leave it switch in then. 

If after you insert the polarity reversal plug and the sound gets worse then you leave it off and work with the sound the way it was before. At least you know it was the right way. This also applies to the snare. Snare sound can either stay great or go worse. Then you try the phase reversal thing on the close snare mic.

If you are going to create a drum sound mainly from the O'Head sound be sure to use fat sounding mikes that can go down low. (AKG 414.s U87's etc) No HPF switches in here also. But if you know you are only just going to add a smattering of O'Heads then you can use say AKG 451's with the HPF switched in hard to get rid of a lot of low end in the O'Head sound. When you do this BTW you get less phase issues with the kick because most of the kick sound now is not in the O'Heads any more to react badly with the close miced kick mic

With a guitar cab you might have a close mic and a distant mic. They may or may not add well either and as you start to balance both of them the guitar sound starts to go bad. So try inverting one with respect to the other and often the guitar sound will change back to being more solid again and fat etc..But if the sound really goes bad after inverting one then you have to go back to what you had before and just balance the mikes better.

Phase problems tend to crop up when you are combining more distant mic(s) with closer ones. (on the same source) especially when the distances from the mics to the source are not the same and one is much closer and the other is a distance away. When two or more mics are the same distance from the source you wont have such a phase problem. When a mic is close and the other is distant it is not a bad idea to measure the distance of the distant mic. That way you can calculate the time delay due to speed of sound. You can then try advancing the distant tracks by the same amount of milliseconds and then you can also improve your sound that way too. (1 ms per foot approx or 3ms per yard/metre)

Thanks guys. Settling down for the night so I'll dig into this tomorrow.

@Jeff... How ya doin', buddy? Thanks for typing all that up. This is obviously a little more in depth a topic than I thought. Heheh. I'll be giving that epic post a good thorough absorbing in the morning. Been watching vids and taking notes all day so it's time to give the old noodle break. Hope you've been well.

Great stuff Jeff.

"Just looking to find out what I should be looking for in the waveforms that would indicate a phase problem."




Keep in mind that you will not see a phase problem on any single track. You will hear the results when the tracks are mixed together.


If you compared a mix with a phase problem to the same content mixed with out the phase problem you might be able to see some evidence in the mixed waveform... or maybe not. The sound of the comb filtering will show up much earlier than any visual clue in the wave form.


best regards,
mike

Beeps, all the advice you got from everyone is spot on. The only thing I want to add is....when something is phasing, you hear an artifact that makes you go "wtf?!" You won't hear it on a solo'd up track....you'll hear it with the mix of other instruments and you'll just know that something isn't right. It almost sounds like a comb filter of sorts has been applied to an instrument if that makes any sense.

The best way I can explain it is....I have a set of Tascam monitors here. You have to hook the wires up to them in 4 spots. Two silver wires, two copper wires. If I do not put the wires in the right way, it messes with the sound of the monitors putting them out of phase. The sound it makes sort of sounds like one of those plugins by PSP that attempt to put a mono track in stereo. Like...in stereo but not quite. But in the mic realm, it adds this artifact that just sounds weird and filtered. Yet when you solo up the track without the other instruments, you can't hear this artifact.

You just listed another thing I hate about videos and tutorials. Man I so want to release mine. I can't tell you how many times I read something or watch something, where the dude talks about something and doesn't show an example. I just don't get these guys. All this knowledge, yet they keep you in the dark about the things you NEED to learn how to listen for. I've concluded that I am the best teacher in the world. LOL! :) (ok, in MY world that is!)

So if you'renot using a bunch of mic's that may be shooting at each other or creating a delay/distance soundscape, this isn't something you'll need to worry about. However, if a dude is mentioning how he checks for phase in a video, he should at least show what phase is as well as an instance on how he actually corrects it.

For me, I usually use the "fix the mic" technique. LOL! However, this plugin from UAD is simply amazing at fixing stuff like this. I've used it so many times, it's starting to replace "fix the mic" and it truly works!

http://www.uaudio.com/media/assetlibrary/l/l/ll_ibp_hq.jpg

-Danny

Hey Danny -
Speaking of videos.......
You still working on that one about HeadCase?

:)

Okay... info absorbed.

@Jeff... That was awesome and very concise. Thank you. I guess maybe what was mixing me up was how it was explained to me originally in the context of a snare drum that had both the top and bottom mic's. They mentioned something about how the top mic's diaphragm would be getting pushed inwards while the bottom mic would be pushing outward and then they would reverse as the sound wave went into the opposite direction. That would cancel each other out when the tracks were played together. I indeed had this issue a few times when I was actually micing my drums oh so many years ago. Now I'm realizing that might be only one angle on it or perhaps completely wrong. What I'm getting now from your post is that a phase problem can happen when the waves are slightly out of sync with each other whereas I was thinking it was if they were too perfect in sync with each other. I'm still struggling to wrap my head around the physics involved but at least I'm confident that if I did indeed encounter a phase issue that I could fix it very easily. It was more my hungry mind looking for more munchies. I'm actually trying to get into learning about physics (like all of physics... not just music) so this type of thing is fascinating to me. Anyway thanks again for such a great breakdown and take care. 

@Mike... Thanks but yeah, I knew that much. Independently everything is fine. The sum of the waves is what can makes things wacky. Pretty neat. Kind of like all this stuff about frequencies getting in each others way in a mix and the various ways of handling it. More physics. Cool stuff and I definitely need to dig into it all more. I'm starting to look at music as pure math more than I ever did. 

@Danny... Yes indeed it is infuriating when something gets alluded to then no explanation is offered. I am taking notes on everything as I go along and when this happens it leaves a gap in those notes. You've seen my writing/teaching style first hand and I definitely try to avoid such things. If delving into the topic would derail the current focus I at least make an attempt state as much and then point the reader to an explanation elsewhere. This series I'm currently watching has given me lots of insight but it is very backwards to how I've learned and approached things. I'm not gonna say it's WRONG because I don't know enough to make that assertion but it definitely seems opposite to what I've seen elsewhere. The results seem to be good though and I'm all for different approaches so I'm soldiering on and it'll get put into my notes as an alternate course of action if something I'm doing doesn't seem to be working. There is however a lot of great info on EQ settings, performing certain procedures in Sonar I was not aware of and probably the most beneficial to me is the fact he is using the method of mixing the drums to the overheads and room mics and using the very minimal close mics (just snare and kick) as helper tracks. I've always approached it from the opposite direction (close mics first then overheads for the cymbals). This will be very useful if I end up in a situation where I have minimal mics/channels to work with and I know this is more like how things were done in the past.

Okay... now I'm just blathering but I wanted to come back and thank you guys. Back to the vids. Cheers.