FORUMS: list search recent posts

TWO shotgun mics - ONE location?

COW Forums : Audio Professionals

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Friedrich Popusismi
TWO shotgun mics - ONE location?
on Apr 15, 2013 at 3:48:12 am

Hi all,

I will be filming a product video featuring two people behind a desk talking. I am a one-man-band and I only own shotgun microphones.

I do have a Zoom H4n that is capable to record stereo with its onboard X/Y stereo condenser mics, but I think I could get better sound if I simply place two shotgun mics closer to the presenters.

Considering that these two people will be no more then a meter apart what would be the best microphone placement option?

Also, what are some of the issues (e.g. phase cancellation, etc.) with using two shotgun microphones in relatively close proximity in order to record this conversation?

Greatly appreciate any help.
Cheers.


Return to posts index

Richard Crowley
Re: TWO shotgun mics - ONE location?
on Apr 15, 2013 at 4:41:02 am

When you say "two people behind a desk talking", would it be safe to assume that this is indoors and not in a cavernous sound stage? With typical near reflections from ceiling, walls, desktop, etc. etc?

Be prepared to learn that there is NO effective microphone placement. Now, you could have some situation where you might be able to get away with breaking the "rule" about using shotgun mics around reflective surfaces (i.e. "indoors"). But if you DO have some unusual situation, we can't tell from what you have revealed here.


Return to posts index

Friedrich Popusismi
Re: TWO shotgun mics - ONE location?
on Apr 15, 2013 at 5:44:38 am

Hi Richard, yes it will be indoors in an office with ceiling, walls, desktops, etc.

As for using shotgun mics indoors: I'd be more then happy if I could capture with my two super-cardioid shotguns anything resembling the quality of audio in the video below, "boomed...not laved" by Mr Ty Ford.

Call me an audio philistine, but I'm fine with using my shotgun mic indoors...I now want to use two of them but I don't know how. :)




Return to posts index


Peter Groom
Re: TWO shotgun mics - ONE location?
on Apr 15, 2013 at 9:09:57 am

Hi
Well youre right not to rely on the zooms onboard mics. Theyre really not up to much and have very little reach.

If you use 2 shotguns to sep record tracks, you only run the risk of phase cancellation if you leave both open together and mono them.
Id record the 2 separately to the zoom split track, and then mix them "bulldozing" the faders gently so that only the best, nearest is up and the other is decreased (not off)
Make sure the cables you use for both mics are the SAME length.
Id position each mic just out of shot NEXT to each other but pointing out over (triangle shape) but only if the performers are to be fixed in position.
If they might move out over a little (apart) then go for 2 positions wider apart pointing in over.
Be clear that phase cancellation only happens in mono and when both mics have a fairly equal value in the mix. Avoid this and you will be fine. LISTEN on cans in MONO to check phase id good.

Personally Id want 2 lavs on them also to PIN their position in the mix, but if you havent got lavs and arent going to get them then ?

Peter

Post Production Dubbing Mixer


Return to posts index

Friedrich Popusismi
Re: TWO shotgun mics - ONE location?
on Apr 15, 2013 at 5:14:27 pm

Thanks for the info Peter. Much appreciated.

When you say "position each mic just out of shot NEXT to each other but pointing out over (triangle shape)", you mean an ORTF or NOS setup placed above the speakers' heads?

The "2 positions wider apart pointing in over" would be a form of a Spaced XY?





As my subjects will be static, my intent is to place the two shotgun mics on a stereo mic stand of some sort and place it on a static mic boom stand immediately above their heads just out of shot. I intend to record these two mono inputs separately (probably straight to my camera rather then Zoom H4n). As the video will go on their website I want it to be mono-proof hence the reason for this post.

Now, considering I will have two sources a meter apart and two shotgun microphones fixed above them, does a correct NOS or ORTF mic placement mean I will be able to record this without any phase cancellation issues?

How is this problem eliminated using lapels? Don't they pick up sound from other sources in close proximity, for example the other speaker in my scenario?


Return to posts index

Bill Davis
Re: TWO shotgun mics - ONE location?
on Apr 16, 2013 at 8:28:51 am

Those plots are for stereo recording. What you're trying to do is dual mono. You want each voice separated into it's own channel with as little bleed as practical between the two signal paths.

The problem with tight long tight pattern mics such as so called shotguns is that they're typically designed for audio capture in a live space with very low noise circuits and significant sensitivity. So each mic will capture both the signal AND a good bit of the sound of the spacial reverb of the location.

Record two signals like that with little space between the elements and you're asking for all sorts of comb filtering as the sound of the audio reflections in the room bounce all over the place and hit the secondary diaphragm slightly time lagged from the same sound hitting the capsule of the primary mic.

This is why a LESS sensitive lav placed very close on each performer helps keep the primary to secondary sounds as separate as possible and will likely yield a better pair of recordings.

Wired lavs are pretty cheap to rent and will work MUCH better here.

If you simply must use the long, sensitive mics, try hard to point them toward absorbitive surfaces and get them as close as you can to the speaking parties - then hope for the best.

Know someone who teaches video editing in elementary school, high school or college? Tell them to check out http://www.StartEditingNow.com - video editing curriculum complete with licensed practice content.


Return to posts index


Peter Groom
Re: TWO shotgun mics - ONE location?
on Apr 16, 2013 at 10:01:32 am

HI
Im not suggesting you use a stereo setup as those diagrams are showing. Record as dual mono, but yes the diagram shows how `id postion the 2 mics if they will stay put!(dont move)

I like the lavs in addition, as they have a tight pickup pattern and will serve to PIN the signal well, as the rifles will by design have more of the off mic sound from the other performer. More complex to rig and record I know, but thats what Id do.
Ultimately it is in the dub / mix where you create or eliminate the off mic material from your mix.
Peter

Post Production Dubbing Mixer


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]