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Dynamic Phase Alignment?
Old 1 week ago
  #1
Gear Head
 

Dynamic Phase Alignment?

Hello,

I recorded an incredible saxophonist recently and was pleased with a great recording. Trouble is, when he was playing his best, he moved around A LOT, which is causing phase issues between the multiple mics.

Is there an auto phase alignment plugin that can compensate for a moving sound source? One that can constantly change the phase/time shift on the fly?

Thanks

Last edited by skillbard; 1 week ago at 07:58 PM..
Old 1 week ago
  #2
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thismercifulfate's Avatar
Your post does not make sense. Did you record him with more than one mic?
Old 1 week ago
  #3
Gear Head
 

The post made sense but I've edited it to be less implicit.
Old 1 week ago
  #4
Lives for gear
 

For the auto-fix' thing- I doubt it. Likely the cure is use the one best of the pair.
Curious what was the placement and intent of having the two mics?
Old 1 week ago
  #5
Gear Head
 

Ah darn it. Okay well thanks Wayne.

We actually had a few mics. We're recording for a video game that has cues that range from a kind of bebop trad sound into much more experimental 'cosmic jazz' territory and also has some super whacky bits along the way.

Because we were getting through so many cues in a short time, we set up a tonne o' mics, ready for use in all situations.

We had:
—A ribbon at about his chin height, pointing down at his fingers, maybe 1.5 feet away
—A dynamic doing kind of the same job but closer
—A condenser focussing more on the bell for a bulbous bottom
—A one of these 'soup can' mics for dirt (actually seems to be far more useful than I'd imagined)
—A room mic

Of course we didn't intend to use all of these at once but, he trashes around so much, the level and timbre is changing noticeably so my hope was that I could try to introduce other mics to help smooth things over. Oh well.

Last edited by skillbard; 1 week ago at 09:40 PM.. Reason: Just being polite
Old 1 week ago
  #6
Quote:
Originally Posted by skillbard View Post
Ah darn it. Okay well thanks Wayne.

We actually had a few mics. We're recording for a video game that has cues that range from a kind of bebop trad sound into much more experimental 'cosmic jazz' territory and also has some super whacky bits along the way.

Because we were getting through so many cues in a short time, we set up a tonne o' mics, ready for use in all situations.

We had:
—A ribbon at about his chin height, pointing down at his fingers, maybe 1.5 feet away
—A dynamic doing kind of the same job but closer
—A condenser focussing more on the bell for a bulbous bottom
—A one of these 'soup can' mics for dirt (actually seems to be far more useful than I'd imagined)
—A room mic

Of course we didn't intend to use all of these at once but, he trashes around so much, the level and timbre is changing noticeably so my hope was that I could try to introduce other mics to help smooth things over. Oh well.
Rule of thumb: the more mics, the more phase problems. Especially when miking a single source.

Another thing, as I suspect you already know, like most acoustic instruments, saxophones emit sound in pretty much all directions -- but the sound can vary radically by aspect/angle of incidence. While it's not uncommon to see the bell close-miked on stage, a more balanced sound is often achieved by a mic a fair distance in front of the sax, since sound comes out the bell, but also from the entire instrument.
Old 1 week ago
  #7
Gear Head
 

Quote:
Originally Posted by theblue1 View Post
Rule of thumb: the more mics, the more phase problems. Especially when miking a single source.

Another thing, it's important to realize that saxes, like most acoustic instruments, emit sound in pretty much all directions -- but the sound can vary radically by aspect/angle of incidence.
Yeah, sure, we're aware of all this and played with mic placement to fix phase cancellation before the session… We just hadn't expected him to move so much.
Old 1 week ago
  #8
Pesky musicians!
Old 1 week ago
  #9
Gear Head
 

Right?!
Old 1 week ago
  #10
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gravyface's Avatar
Quote:
Originally Posted by skillbard View Post
Yeah, sure, we're aware of all this and played with mic placement to fix phase cancellation before the session… We just hadn't expected him to move so much.
Can you slide the tracks around and align it?
Old 1 week ago
  #11
Gear Head
 

Quote:
Originally Posted by gravyface View Post
Can you slide the tracks around and align it?
I can but there's about 45 mins of audio… I can't be automating sample shifts across all that!
Old 1 week ago
  #12
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Quote:
Originally Posted by gravyface View Post
Can you slide the tracks around and align it?
For multiple amounts of shifting arrival times -per mic, as the player shifts about?
Old 1 week ago
  #13
Here for the gear
This plugin claims to do the trick: https://www.soundradix.com/products/auto-align-post/
Old 1 week ago
  #14
Gear Head
 

Quote:
Originally Posted by woylie View Post
This plugin claims to do the trick: https://www.soundradix.com/products/auto-align-post/
Exactly what I was talking about!!! Thanks so much.

But, darn it, I no longer have Pro Tools… I guess I'll have to pull in a favour and see if this works. Thanks again!
Old 1 week ago
  #15
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Quote:
Originally Posted by woylie View Post
This plugin claims to do the trick: https://www.soundradix.com/products/auto-align-post/
I only glanced at the info. How's it at tracking\correcting varying phase via the source moving around ?
Old 1 week ago
  #16
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Movement will change the timing of sound reaching different mics. Those mics could have been out of phase even if he had remained stationary. His movement only made it worse.

I've worked professionally with several different sax players. The ones I worked with hated using stationary mics. In our live shows I eventually got them hooked up using a mobile mic that clips to the sax, therefore eliminating any dropouts a stationary mic produces. There is a learning curve that comes along with that too because they are typically used to working a stationary mic in order to fade notes or increase volume levels during a solo. When they first get a clip on every note is the same volume. If the system is designed for sax they typically have a small adjustable preamp they can clip to their belt and adjust the volume. Or like a guitarist use a volume pedals and effects.

If you use a stationary mic for recording, then get a hammer and nails and nail his shoes to the floor. he can still weave around quite a bit but he'll at least be close enough where a compressor can handle most of the volume swells.

As far as trying to fix what you got using multiple mics my suggestion would be to pick out one mic, preferably the one with the lowest noise floor.
If then put the track in Har Bal which is able to limit the entire track and level its volume without having to first read the volume change as most standard compressors do. Har Bal scans the entire file and already knows where the volume changes before limiting is applied. It doesn't have to try and apply changes in real time, it calculates the changes needed before you even begin.

I would NOT use a compressor. A compressor will try and raise the noise floor and therefore create swells of noise. Its better to boost the entire track then bring the peaks down to match the lowest levels. After that you use a good noise removal tool or even a gate to clean up any noise between notes.

if that doesn't pan out, start over and do it right next time. You'll find many who prefer a stationary mic. That's a debatable point. If the room sounds great and the player knows how to use a stationary mic well then go for it. if the person is a beginner when it comes to being miced, a high quality clip on mic can be a real life saver. What you gain with having a steady volume far outweighs higher quality loaded with constant dropouts. Unless you're a glutton for beating your head against the wall drawing volume curves is the only other option and its only going to produce mild improvements. I wouldn't even attempt to try and fix phase issues. I've done it with drum mics but they don't move around and make that problem worse. I can tell you right off there aren't any tools that will undo this using automation either. Bout the best tool you can use is a dual trace oscilloscope and attempt to keep pone track in phase with the other manually riding a phase shifting tool. You'd likely have to rehearse the moves for hours to get it close enough for prime time and even then the odds there aren't other issues involving different frequency responses of the mics makes it a very palatable effort.

Good luck in any case. Better you then me.
Old 1 week ago
  #17
Here for the gear
Quote:
Originally Posted by Wayne View Post
I only glanced at the info. How's it at tracking\correcting varying phase via the source moving around ?
Alas, I have not tried the software. I was just notifying of its existence. If they have a found a way to consistently find, and smoothly adjust to, an "optimal" phase alignment in evolving 3D space, that is quite an achievement!
Old 1 week ago
  #18
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Quote:
Originally Posted by woylie View Post
Alas, I have not tried the software. I was just notifying of its existence. If they have a found a way to consistently find, and smoothly adjust to, an "optimal" phase alignment in evolving 3D space, that is quite an achievement!
Yeah. I'm just considering shifting in time (-let alone tracking this? w/o artifacts in the digi domain is no trivial mater! :>)
Old 1 week ago
  #19
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iangomes's Avatar
I was going to say Auto-align Post as well. Did it work?
Old 1 week ago
  #20
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Robo's Avatar
Not used these but some options to try:

Soundradix Pi
https://www.soundradix.com/products/pi/

Melda MAutoAlign
https://www.meldaproduction.com/MAutoAlign

Last edited by Robo; 1 week ago at 04:50 AM.. Reason: Wrong plugin
Old 1 week ago
  #21
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iangomes's Avatar
Pi might work better than auto align for this, actually. I think it’s dynamic?

Quote:
Originally Posted by Robo View Post
Not used these but some options to try:

Soundradix Auto Align (VST)
https://www.soundradix.com/products/auto-align/

Melda MAutoAlign
https://www.meldaproduction.com/MAutoAlign
Old 1 week ago
  #22
Just choose the best mic, and work with that. Dynamic eq can work wonders for reducing proximity effect. If there’s an ambience change, you may be able to compensate by riding a room verb send.

Attempting to dynamically rotate phase for multiple mics is going to be hell. Avoid at all costs.

Auto align etc are static adjustments. I’m not even 100% sure you could do what you’re thinking - you’d probably need to find the best static positions for sections and automate between them. Not fun for 45mins.

I’d forget about phase issues and concentrate on evening out tone.

I’m not sure how raising them overall level then compressing the peaks is any different to compressing and then using makeup gain but hey. If noise is an issue use a good denoiser plugin first. Gating a noisy signal could make the noise more noticeable not less!
Old 1 week ago
  #23
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iangomes's Avatar
Quote:
Originally Posted by psycho_monkey View Post
Just choose the best mic, and work with that. Dynamic eq can work wonders for reducing proximity effect. If there’s an ambience change, you may be able to compensate by riding a room verb send.

Attempting to dynamically rotate phase for multiple mics is going to be hell. Avoid at all costs.

Auto align etc are static adjustments. I’m not even 100% sure you could do what you’re thinking - you’d probably need to find the best static positions for sections and automate between them. Not fun for 45mins.

I’d forget about phase issues and concentrate on evening out tone.

I’m not sure how raising them overall level then compressing the peaks is any different to compressing and then using makeup gain but hey. If noise is an issue use a good denoiser plugin first. Gating a noisy signal could make the noise more noticeable not less!
I believe that this is exactly what Soundradix PI does. It dynamically rotates phase between channels based on the weightings you give each one. That said, who knows if it would actually sound good in this situation.
Old 1 week ago
  #24
Quote:
Originally Posted by iangomes View Post
I believe that this is exactly what Soundradix PI does. It dynamically rotates phase between channels based on the weightings you give each one. That said, who knows if it would actually sound good in this situation.
Fair enough - I don't know this plugin.

I have to say, personally I've never found a phase rotation or auto alignment plug useful. Occasionally I've slipped a Bass DI in line with an amp, but that's about it.

I really think that attempting to match up 3-4 mics is a losing battle. MAYBE you might get lucky with this plug and the two most useful mics.

I'm a big fan of keeping it as simple as possible, and that would mean for me removing the issue of phase alignment totally.
Old 1 week ago
  #25
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gravyface's Avatar
Besides a clip-on, what's the go to here? Omni a few feet away?
Old 1 week ago
  #26
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chrischoir's Avatar
 

They should make 3 dimensional DAWs. We could phase align every frequency as needed and avoid this problem. It shouldn't be to tough with modern implementation of a Fourier Transforms on GPUs
Old 1 week ago
  #27
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JoeyM's Avatar
Quote:
Originally Posted by chrischoir View Post
They should make 3 dimensional DAWs. We could phase align every frequency as needed and avoid this problem. It shouldn't be to tough with modern implementation of a Fourier Transforms on GPUs
Yeah and a Jim Williams mod to give us more ears
I mean, we've been getting by with two ears all this time, that's it?
Old 1 week ago
  #28
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chrischoir's Avatar
 

Quote:
Originally Posted by JoeyM View Post
Yeah and a Jim Williams mod to give us more ears
I mean, we've been getting by with two ears all this time, that's it?
Well you raise a good point. It really comes down to experience. I will say to play devil's advocate, we have all made mistakes though and wish we could fix something after the fact. The LL IBP can get you out of a bind but not always.
Old 1 week ago
  #29
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Robo's Avatar
Quote:
Originally Posted by iangomes View Post
Pi might work better than auto align for this, actually. I think it’s dynamic?
You're right, that's the one I meant. Thanks! Edited.
Old 1 week ago
  #30
I think you’ll probably waste a lot of time with phase alignment plugins and still not be happy.

Pick the best single mic at any one time... choose different ones for different cues or musical sections and make that a thing. It sounds like you’ll have a whole lot of different colors to choose from... just don’t try to use them all at the same time.

You can create dimension in so many other ways these days.
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