Time alignment -UM400a and Boom mic

[JackHenry]

Could you calculate it based on the assumption that the speed of sound is roughly 344m/s, or would there be an additional delay introduced because of the processing within the UM400?

Jason

 

It's about a millisecond per foot.

[podgorny]

Tom, distant recording sounds different from close-micing because of the inherent loss of treble and of course the interaction of the room (which is why I said "in an anechoic chamber").

And I know what the 3:1 rule is. I was referring to using multiple lavs on multiple individuals.

[Constantin]

Additionally, "phase issues" as we are discussing here cannot happen with only one microphone, unless you are talking about picking up slapback echo from somewhere. This is about comb-filtering that results from two microphones picking up the same source.

Not necessarily slapback. You only need two sources for phase issues, not two mics. The more similar the sounds, the easier it is to have phase issues. So the reflection of a sound can cause phase issues. Although it is true that this is not particularly relevant to this thread. But it does highlight that it is pointless to try to get rid phasing problems on set.

[minister]

Tom, distant recording sounds different from close-micing because of the inherent loss of treble and of course the interaction of the room (which is why I said "in an anechoic chamber").

Waveforms change due to refraction, temperature lapse, temperature inversion, (as well as interior room or outdoor object interaction) and the speed of the sound is dependent on the inertia and elasticity of the medium through which it travels.  Warm air, cold air, water, reality.  During the day you may not hear those people across the lake, but at night, due to temperature inversion (high above air is cooling, near the ground the air is still warm) you hear them quite clearly.  The temperature inversion causes the waveform to bend downward, in other words, change.  We record in reality, not in ideals.  Several feet, and, yeah, the waveform might be close to the same.

 

Also, one of the tricks in post to make things sound farther away is roll off low end, not high end.  So, it's not just high end frequencies that get affected.

[podgorny]

Is there a facepalm smiley on this forum?

I thought we were discussing mixing lavs and boom, not lavs and a microphone on THE OTHER SIDE OF A LAKE.

[Constantin]

Is there a facepalm smiley on this forum?

I thought we were discussing mixing lavs and boom, not lavs and a microphone on THE OTHER SIDE OF A LAKE.

Well, you brought up the anaechoic chamber...

In the real world, where most of us work, there are lots of reflective surfaces and they do affect and effect the sound. So, to get back to the original point (and I do think that most here are in agreement, but for very different reasons) there can even be phase issues if both mics are at the same distance from the source, but with the boom picking up more reflections

[studiomprd]

" Is anyone uncomfortable with THIS amount of delay? "

maybe, and I'm guessing you are, but not me.

 

" would there be an additional delay introduced because of the processing within ..."

yes, any digital conversions and processing add additional delays.  (that is, I believe,  what this thread was originally about)

Edited June 24, 2013 by studiomprd