Shotgun Stereo Mic Question

gco

gco

Veteran
Probably a dumb question here but I am not understanding how a stereo shotgun mic feeds L/R channels into the cam.
On my HMC both channels 1 and 2 are set to XLR input 2 so that my mono shotgun feeds both channels.
If I swap the mono mic for a stereo mic, I would assume both channel switches are set the same so both channels receive audio signals.
How are the two channels separated? Does the camera detect the difference coming from the mic or are the mic connections to the XLR plug different?
Any light in this darkness greatly appreciated.
 
A stereo shot gun mic such as the Audo Technica BP4029 has two separate outputs that go to input 1 and input 2 on your camera. The microphone has 5 pins and needs a special cable that breaks that out into two separate channels on two different XLR connectors.
 
Ok, That makes sense.
That was actually the mic I was looking at but the connection aspect wasn't clear.
Thank you sir!
 
I have one of these mics, works great. The only minor issue is the figure-8 mic is a bit noisier than the shotgun (far cheaper and simpler than doing with Schoeps parts, so great bang for buck). I use the free MSED plugin in post (never use the built-in matrix modes). It comes with a 24" 5-pin to dual 3-pin XLR. https://www.audio-technica.com/cms/wired_mics/9087c643d6d7530f/index.html . I've also got a 25' 5-pin XLR cable for mounting off camera. For POV / VR shots, the 4029 sounds excellent spatially on headphones- you'll turn around sometimes thinking sounds are live during playback! (mid-side stereo)

Processing mid-side in post, you can get 3 channels as well as control stereo width. You can invert the phase and get 3 more channels (sort of- the back channels will be attenuated somewhat due to the shotgun design). Summing the channels and keeping only the low frequencies gets your .1 (sub) channel. Of course you could also mount another shotgun pointed directly backwards for the traditional double mid-side for full true 5.1 support.
 
gco said:
Is there a reason you prefer mid-side vs. traditional left-right?
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Yes- you can tune stereo width in post, from mono to ultra wide stereo and anything in between. The 3D playback aspect is also super cool.
 
Got it. I'm treading into some new territory here so thanks for the input. Really appreciate it.
 
I have used a bunch of stereo mic configurations. But my go to most of the time is an MKH30 paired with either an MKH50 or MKH60 depending, run into a Sound Devices mixer/recorder so I can monitor M/S.
 
I have been involved in Broadcast TV Audio for more than 35 years, while MS can be interesting I have abandoned it due mainly to some inherent problems with matrixing and network issues.
If you go down the MS path make sure that EVERYONE...... and I do mean EVERYONE that has access to the files during recording, editing and post production...FULLY understands MS and how it works. MS can be stuffed up if handles wrongly.
Do not EVER push the MS image super wide or you will have mono / mixing compatibility problems, especially if the material is to be broadcast at some point in its life.

XY is a better format for people that are new to production, it handles like standard stereo sources.. i.e. Music, video clips etc.
AB is better for wide screen TV broadcasting and interchangeable with XY.

Stereo mics and shotgun mics are sort of each end of the spectrum...... 'Stereo' you want width and a 'Shotgun' you want a narrow pickup angle...
 
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Dozens of times I've gone into TV network edit studios only to get the comment that 'Ch2 sounded odd.... so we have deleted it and just gone with the Ch1 Fx'
Good one they have just deleted the side track of the MS.
 
I feel there is no real need to record M/S these days as some consoles and audio systems such as Pro Tools have controls or plug ins to adjust stereo width of an AB stereo signal in post.

It is useful to have an M/S mic though as the mono capsule is always pointing forwards and therefore capturing the action even when a camera or boom is moved.

I would always record AB though and have done so with my two long time M/S mics the Sony ECM-MS907 and ECM-MS957.
 
GaryNattrass said:
I would always record AB though and have done so with my two long time M/S mics the Sony ECM-MS907 and ECM-MS957.
Click to expand...

I saw ECM-MS957 and thought it looked familiar. Went into a mic/accessory drawer and found a mic I haven't used in over 10 years- an ECM-MS957. I remembered it took a battery and opened it up hoping not to see any corrosion. There was none, and the 2006 (exp.) Duracell still works! Great mic for Foley/SFX. For camera work I prefer the AT BP4029 (stereo/camera FPV) and for 3D using the same basic phase concepts using 4 capsules (ambisonic), the Sennheiser Ambeo.

If I needed top quality M/S I'd add the Schoeps CCM8 to the CMIT5U, and if needing double M/S, further add the CCM4. A buddy uses this set up for capturing 5.1 and he loves it (think he might be using two CCM4's and no CMIT5U). This is probably the most compact, ultra high quality way to capture 5.1, though I'm not sure it's worth the cost over the Ambeo (which capture full 3D). Found this, for planar 3D, makes sense that double M/S sounds better, especially if using Schoeps mics: https://www.gearslutz.com/board/rem.../1207436-double-m-s-gt-4ch-contemplation.html
That said, there's a lot of ways to process ambisonics in post, so who knows what they used. I can say the budget BP4029 can produce spectacular planar 3D effects on speakers and headphones, which are good enough to make one turn around during playback for the life-like sound of an opening door, cat/dog, etc.
 
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