Phase Cancellation Question/Confirmation/Clarification

[MarvinG]

OK - I searched through here on HRF and did a bunch of reading so this is really just a confirmation on whether or not I am understanding a specific aspect of phase cancellation:

1. My understanding is that phase cancellation could be occuring in my mix that I am NOT hearing on my monitors... I could possibly mix down, master, and distrube the music and if (and only if) someone out there is listening on a "bad" speaker or in mono, phase cancellation could occur this far down the line for the end user?

So, as in, I would never know and most people would never hear it but randomly someone might be listening on a system or mono configuration and say the vocals or snare drum are cancelled out for this listener?

2. I need to eather do a mono test BEFORE I mix down or use a visual phase monitoring plug in to ever detect this above scenario (if in fact it really exists)?

Thanks guys! As Always, I get so much from here and in the archives of threads, I really appreciate the forum!

 

[MarvinG]

PS - I am actually hoping nobody has any idea what I am talking about and I misunderstood something along the way. So yes, I realize this entire thread may sound a bit ridiculous, but I swear I read something like this and now I am thinking I have recordings floating around out there with pieces of the mix missing for certain listeners because I never bothered to check for phase cancellation!

 

[Steenamaroo]

It's good practice to check in mono, especially in club music genres.

Check this : Get a sine wave on a mono track. Duplicate it and pop the polarity of one. You don't hear it right?
Now pan one hard left and the other hard right.
It might be a little dizzying but you can hear them?
Someone listening in mono wouldn't.

Now, that sine wave was an extreme example but there could be plenty of natural information in a stereo mix that'd cancel out in mono.

With live music it's usually something you combat at the source. If things are miked and recorded well to start with, a lot of problems are avoided.

I wouldn't worry about people listening on bad speakers. There's nothing you can do about that.
Hope that helps.

 

[MarvinG]

I definitely will begin checking in MONO on every project going forward. I am wondering more for my stuff that is already out there, could there be phase canx on tracks that I (or others) would never hear but some would hear? Or is it a situation where by the time it is mixed down, mastered, and packaged in a single file "what you hear is what you get" and things like phase canx are not going to pop up?

It's good practice to check in mono, especially in club music genres.

Check this : Get a sine wave on a mono track. Duplicate it and pop the polarity of one. You don't hear it right?
Now pan one hard left and the other hard right.
It might be a little dizzying but you can hear them?
Someone listening in mono wouldn't.

Now, that's a pretty extreme example but there could be plenty of natural information in a stereo mix that'd cancel out in mono.

With live music it's usually something you combat at the source. If things are miked and recorded well to start with, a lot of problems are avoided.
Hope that helps.

 

[Steenamaroo]

Or is it a situation where by the time it is mixed down, mastered, and packaged in a single file "what you hear is what you get" and things like phase canx are not going to pop up?

No, it's still an issue.
Re read my sine wave example. If you used a sine wave synth as a lead and decided to double it out, pan apart and flip polarity of one for that "oh so super cool stereo effect" It would literally disappear in mono playback.

If you recorded a guitar amp with two mics and panned the results apart it could sound very different to if the mics were panned straight down the middle, especially if your mics were at different distances from the amp.

That said, you usually you have to do something pretty extreme to hear a big problem, yeah?

 

[bouldersoundguy]

Definitely check your mixes in mono. Sooner or later they'll be played back that way and you don't want any embarrassing surprises.

Last year I had the rare pleasure of hearing one of my mix/master jobs on the radio. When it came on I thought, "That's familiar. That's really familiar. Where have I heard that? Oh, god, that's my mix! And it sounds...pretty good." It was on an FM station that's talk most of the time so they broadcast in mono. But the mix held up just fine because I mix with mono compatibility in mind.

 

[snow lizard]

Slight tangent to the discussion but if you record with more than one mic on a source then phase cancellation will be an issue.

By no means is this to suggest a scenario like thinking "Oh my god... there's PHASE??? THAT'S TERRIBLE!!!"

No worries. It's always there to some extent.

But it might be an issue. Or not. Simply compare two mics against each other in mono. Invert the polarity on one of them. If there's an obvious improvement on one setting or the other (louder, more bass etc...) you can leave it that way. It means the mics are close to being either in phase or somewhere around 180 degrees out. If the differences are negligable you might try tweaking the mic placement a bit. Unless it sounds great, in which case don't sweat it too much.

It's a big reason why relatively few mics on a drum kit in a good sounding room can sound excellent.

It's also a reason why many very cheap large diaphragm condenser mics can sound thin and difficult to control. Crappy phase response. Built in filters are common, but the comb filter is not desirable. Room treatment helps too, but not to fix a crappy mic.

As for mixing, checking for mono compatability is a mighty good thing to be doing, as already said. Mono compatability will not make your mix translate to a wide variety of systems. Until you learn and understand how your monitors translate to other systems it might be a good idea to test it on a variety of challenged systems before finishing it. Try the car too.

2. I need to eather do a mono test BEFORE I mix down or use a visual phase monitoring plug in to ever detect this above scenario (if in fact it really exists)?

Mono test before.

Visual phase monitoring plug? Not extremely useful. Learning to hear it will serve you much better.


It really exists.

 

[witzendoz]

There was a local band here that had a hidden track in mono under a stereo track, what they did was during a long instrumental section they put the stereo out of phase so that it was wider, however under the stereo track was a mono mix of a completely different song. So if you played the track in mono when the instrumental section was reached the stereo track would disappear and the now mono song played. Very spooky.

Alan.

 

[ecc83]

An absolute phase change is a polarity flip. That which is commonly called a "phase problem" is generally comb filtering caused by differing arrival times at the mics.

It is moot to remember that whilst balanced operation is generally a "good thing" wires can get crossed and an Out Of Phase lead go unnoticed unless you check for it. Anyone looking for a simple, passive starter electronics project could do a lot worse than build an XLR/TRS polarity flipper and a mono'ing box to go in the feed to their monitors (assuming there is no other means to mono the monitor feed.

Anyone making up their own leads should also build an LED OOPs detector.

Dave.

 

[Bobbsy]

Anyone making up their own leads should also build an LED OOPs detector.

Dave.

Yup. Even though I know the problem the number of times I've been caught out forgetting I'd swapped from a male XLR to female (or vice versa) and built a bad cable is embarrassing to admit.

Nowadays, if I'm doing a bunch of cables I do all the male ends first, have a coffee, then do all the female ends to try and avoid making mistakes. It USUALLY helps...

 

[ecc83]

Yup. Even though I know the problem the number of times I've been caught out forgetting I'd swapped from a male XLR to female (or vice versa) and built a bad cable is embarrassing to admit.

Nowadays, if I'm doing a bunch of cables I do all the male ends first, have a coffee, then do all the female ends to try and avoid making mistakes. It USUALLY helps...

Ah, now! You know there are weird people that LOVE ironing? Or washing the car?
Well, I love making up cables!

One of the many things I miss from work (tho there are plenty of things and people I don't!) is sitting down with me trusty Magnastat, vice, kit, heatshrink and silicone grease and making up all sorts of leads. I especially liked making multipin 15way footswitch cables because of the concentration needed and the pleasure of a really good job done.

If I were ever really on my uppers I would make "bespoke" cables and flog them on the net. I could still do with a bit of extra cash but there is a first class guy here, Rob of "Kabl cables" and he does it for a PROPER living. No fair I should cut in.

Dave.

 

[Bobbsy]

Actually I'm much like you. I find an afternoon of cable making like my wife does with crocheting. Give me the necessary hardware plus a pint mug of tea and Radio 4 or the World Service to listen to and I'm a happy bunny.

Even better if it's raining outside.

Perhaps we should team up and start a business ripping people of with hand made audiophool cables ?

 

[ecc83]

Actually I'm much like you. I find an afternoon of cable making like my wife does with crocheting. Give me the necessary hardware plus a pint mug of tea and Radio 4 or the World Service to listen to and I'm a happy bunny.

Even better if it's raining outside.


Perhaps we should team up and start a business ripping people of with hand made audiophool cables ?

Ha! YOU could say "Exotic imports from Europe" and I could say "Exotic imports from Ozz"!

Can you get BBC radio 4 then? and Radio 3? Love to know how because #1 Son is only a few hundred clicks away in France but he misses the Beeb something rotten.

For me it would be R3. R4 would be too interesting and distracting. And I am a coffee man.

Dave.

 

[miroslav]

Actually I'm much like you. I find an afternoon of cable making like my wife does with crocheting.

Maybe you guys could start a cable making circle.






I'm not crazy about making cables, but when I have to, I'll just get comfy at the table and make cables all day while watching TV.
I remember spending a couple of weeks cable making when I first wired up my studio.
I did like a dozen or more 48-channel snakes with connectors on one end and patchbay points on the other.
That was tedious, but needed to be done.
It took a few days to get the smell of solder out of my nose.

 

[rob aylestone]

Phase cancellation can happen without you being aware when listeners are different distances away from the speakers, so if you get it right for the usual centre between speakers position, it's possible for weird things to happen when speakers are larger distances apart. I doubt anyone has ever guaranteed a perfect mix everywhere.

 

[Bobbsy]

Ha! YOU could say "Exotic imports from Europe" and I could say "Exotic imports from Ozz"!

Can you get BBC radio 4 then? and Radio 3? Love to know how because #1 Son is only a few hundred clicks away in France but he misses the Beeb something rotten.

For me it would be R3. R4 would be too interesting and distracting. And I am a coffee man.

Dave.

OT but yes, I can get all the BBC radio channels via their live streaming on the web. For that matter, streaming is even my source for the World Service--they switched off their short wave transmitters for this region ages ago.

 

[ecc83]

OT but yes, I can get all the BBC radio channels via their live streaming on the web. For that matter, streaming is even my source for the World Service--they switched off their short wave transmitters for this region ages ago.

How odd! My son could not get it in France when he went over there about 3yrs ago and I assumed it was because the BBC did not want non-license payers getting the service.

I shall get onto him PDQ and tell him to have another bash. NOW dad is going to have to stump up for a copy of Win7 for him since his laptop is still XP and will soon be useless on the Web.

Dave.

 

[Bobbsy]

Strange. I'm listening to the "Today" show as I type this just using the beeb's own iPlayer but also have an app on my phone called Tune In which can receive it as well.