sdauditorium
Active Member
Care to elaborate? I may not be anywhere near an expert on the matter, but no one has ever told me that a musical that I mixed didn't sound good (or at least as the performers' original voices that is...).
Microphones Phase Cancellation?
- Thread starterMilesDenison
- Start date
Care to elaborate? I may not be anywhere near an expert on the matter, but no one has ever told me that a musical that I mixed didn't sound good (or at least as the performers' original voices that is...).
pmolsonmus
Active Member
It's physics as museav explained better than I could. Whenever the same source hits mics at different times the waves overlap to some degree as they are joined together at the mixer. A little or a lot, barely audible to a complete change of tonal color that is result of that cancellation.
Its is electronically possible to record something, duplicate it and invert the phase (or even the polarity on a speaker) and have the two sounds completely cancel each other out. The wave + its inverse = null. Its a trick that is used in recording to remove backing accompaniments from a vocal track so the vocal track can be eq'd and tweaked separate from the accompaniment if the accompaniment is picked up by the vocal mic.
This phenomenon can't be avoided in live theater as the other posters have commented. It is what makes mixing live theater incredibly difficult, there is no "set it and forget it" option that is universal.
With 20+ body mics and 10 hanging mics in combination those phase issues are happening. I'm not saying your mix is necessarily bad, but phase cancellation is unavoidable and your set up sounds like a recipe for it. The best you can do is as the other posts suggest. ABA - always be adjustin'.
The problem is most noticeable when actors are close to two or more mics that are in close proximity (e.g duets) The sound will usually change significantly as the actors move. The challenge is to make it sound like there has been no change - not an easy task for even seasoned pros until they are familiar with the show and the actor's tendencies.
Phil
Its is electronically possible to record something, duplicate it and invert the phase (or even the polarity on a speaker) and have the two sounds completely cancel each other out. The wave + its inverse = null. Its a trick that is used in recording to remove backing accompaniments from a vocal track so the vocal track can be eq'd and tweaked separate from the accompaniment if the accompaniment is picked up by the vocal mic.
This phenomenon can't be avoided in live theater as the other posters have commented. It is what makes mixing live theater incredibly difficult, there is no "set it and forget it" option that is universal.
With 20+ body mics and 10 hanging mics in combination those phase issues are happening. I'm not saying your mix is necessarily bad, but phase cancellation is unavoidable and your set up sounds like a recipe for it. The best you can do is as the other posts suggest. ABA - always be adjustin'.
The problem is most noticeable when actors are close to two or more mics that are in close proximity (e.g duets) The sound will usually change significantly as the actors move. The challenge is to make it sound like there has been no change - not an easy task for even seasoned pros until they are familiar with the show and the actor's tendencies.
Phil
You mentioned running 20 E6s and 10 AT853. On one hand the E6 really helps as even though it is omni it puts the mic very close to the one talker's mouth and performers might have to get pretty close together to have level and path length differences that would be audible. Try the same thing with a hairline or tie clip lav and you may get very different results.
Another possibility that may be relevant is that if you are dealing with two microphones the phasing is the result of the differences between a sound at mics A and B, one set of interactions. But make it three microphones and you are then looking at the relative relationships of mics A and B, mics A and C and mics B and C, three different sets of relationships. Four mics may have six different relative phase and level relationships each causing different anomalies. Eventually you get so many relationships that the various cancellation and summations may start to offset one another. Essentially, with many microphones picking up a sound and especially with minimal level difference at the microphones then the phasing or combfiltering can get so dense that the overall effect is limited.
Or if you have any pre-fade sends for effects, recording, ancillary areas, program feed to comms, Assistive Listening feed, etc. Both in assigning a send pre or post fader and in deciding where to make gain changes you have to think about what it really is you are trying to do and how you want it to affect or be affected by different changes.
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