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We occasionally have a situation where one speaker is wearing a wireless microphone and another speaker is not. (Usually a translator would be using the wireless headset, standing next to a guest speaker).

When the speaker wearing the wireless headset moves away or nearer to from the fixed mic, a sweeping phase sound is audible.

No one has complained so far and I hope I'm the only one hearing it, but I'd like to fix it for the recording (at least).

So far I have only found static plugins like InPhase, Auto-Align, and so on, but these do not add or subtract delay dynamically with the moving mic. I'm sure it shouldn't be hard to do the following part (phase-locked-loop style of follow the leader), but I guess that smearing the difference in delay out smoothly could be a relatively heavy process.

I've been searching with various keywords like "Doppler compensation", "dynamic phase correction" and so, but maybe I'm using the wrong ones? The closest I could find was Pi but the description is a bit fuzzy about what it's actually doing.

A similar thing happens with a mic above a white-board and an overhead "shotgun" mic pointing to the whiteboard from the sealing. When the speaker walks to-and-fro between these two mics there would also be some phase shifting. Though I havn't been able to audibly identify these (yet) I'd still like to keep them in-phase.

It would be even greater if we could have such correction in the Live setting, but for now I'd settle with a plug-in when mixing down the final recording.

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    Why not simply use a more directional mic for the stationary speaker so that you don't get the cross talk issue at all? If you can isolate the channels so each mic only pics up the relevant speaker you will get better sound quality and the phase issue will go away. – AJ Henderson Dec 3 '13 at 21:41
  • True, we have considered a more directional mic there, but it would also constrain some speakers who like to move a little while passionately expressing themselves. Having each speaker wear a headset would be the "42" solution, but unfortunately that is not always feasible (with different speakers following each other up, it would be quite a hassle). We finally settled with this trade-off. Occasionally I also fade-in an overhead shotgun mounted on the sealing when a speaker walks away too far from the main mic. – Louis Somers Dec 3 '13 at 22:00
  • You can still use the existing solution as a backup and avoid the problem 90-95% of the time. :) – AJ Henderson Dec 3 '13 at 22:38
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    I mean use the compressors to gate the mics. So, speaker #1 talks, it gates speaker #2. – Don Nickel Dec 23 '13 at 17:56
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    @DonNickel If you add your tip as an answer, I'll mark it as an answer! Finally got the chance to test this yesterday using the "duck" function on the main mic triggered by the translators mic. I tweaked it so that the ducking effect is inaudible but enough to get the phase shifting effect inaudible as well. It worked out great! – Louis Somers Jan 25 '14 at 13:41
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What you actually need here isn't a "phase aligner", it is an automixing solution like the Dugan automixer. This is built in to some of the higher-end recorders like the Sound Devices 788T or 688T but is also available as a plugin - I believe that Waves supply a Dugan automixer.

An automixer has the ability to automatically manage the gain of a suite of microphones so that phase artifacts are minimised. Only an active microphone is going to be mixed in to the output bus, however it is clever enough to always leave at least one mic live so that you don't get dropouts.

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    Sorry I'm a little late to respond, didn't get to digging into what a "Dugan Mixer" does until an hour ago, but Thanks for this tip! I first checked out what a Dugan Mixer was, (thinking it would be a clever expander or so), and starting be become convinced, bumped into a link to a youtube introduction of a new firmware update for the mixer we are using, which actually has a Dugan Mixer added as the main new feature, downloadable for free! The demo's really look convincing and I don't need to purchase any extra hardware or software! Wow, you got me exited now :-) Thanks again! – Louis Somers Dec 8 '16 at 22:20

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