It all started when I bought myself a Zoom F6 audio recorder from eBay. I wanted to test this unit in order to make sure it was functioning properly. So I thought to myself “what would warrant using a bunch of channels?” and the first thing I thought of was a surround (5.0) ambience. I’ve mostly just recorded ambiences in stereo, as well as a handful in the ambisonic format. I have a studio equipped with 5.1 playback and a whole bunch of assorted mics, so I figured I could hack a rig together and give it a shot! So I was off to the drawing board…
The first thing I did was read this useful article on DPA’s website outlining ‘immersive’ mic techniques. I was astounded at all the various combos available. I read this and absorbed some general do’s-and-dont’s in my head, realized that what I was about to do was not going to be super mathematically perfect, and mostly forgot about what I had just read. I figured that I could listen back in my studio and let my ears be the judge. I also could check the stereo mixdown compatibility for phase issues and determine a workable mic arrangement from there, since no one likes phase issues!
After a bunch of hemming and hawing, I landed on the following arrangement:
LR = Sennheiser MKH8040 in ORTF
C = MKH60 Shotgun (bungie corded above the ORTF rig in a very sketchy fashion)
LsRs = An MS setup with the Line Audio CM4+Sennheiser MKH30
Why the hell did I choose this set of mics? For one, I only own two proper blimps, and this meant I could keep most of the mics within those, because wind is my number one enemy when out in the field. The center mic, the MKH60, ended up lazily bungie-strapped to the top of the ORTF blimp rig positioned roughly in the center with a Rycote ‘Softie’ windscreen. I kept the mic in a shock mount to allow for easier bungie cord wrapping. Yes, I know, this is far from conventional, but hey, it was an experiment!
Initial Testing
I threw this up in my suburban backyard and recorded the general daytime ambience as a test. I moved the LCR and LsRs rigs to various distances for comparing later on. I started at “point blank” or near coincident with the blimps on top of one another. Then I moved them to 15″, 30″, and finally 50″ apart. I had no idea what the hell I was doing but it felt very scientific. I recorded each distance for roughly 3 mins. I took the recording back to the studio to listen to the results…
After a bit of leveling out the gain to have a somewhat even surround field, what I found was that overall it sounded fine and there were no noticeable differences with the various distances between rigs. The one thing I did not like was how the center channel stuck out in terms of signal coloration compared to the L and R channels. In my original plan, I had chosen the shotgun mic mostly because that mic has low self-noise, but unfortunately the long reach of the mic was really changing the tonality of the sound (in this case it picked up a neighbor’s pool cleaning machine really well). Also, when I had performed a walk around test where I spoke continuously as I walked around the mics (very scientific, trust me), I could hear the rear pickup of the MKH60 come into play when I was 180 degrees behind the microphone. For those of you who aren’t aware… shotguns/super-cardiod pickup patterns inherently reject off-axis sound, except for the signal directly behind the mic capsule. It’s easy to forget this fact, and I’m glad I did this little walk around talking test since it was another factor that made me change this center channel mic…
So I swapped out the MKH60 with a line audio CM4 to better match the polar pattern of the ORTF setup it was sitting on top of. The CM4 is a bit noisier than the MKH8040s, but whatever… this was all an experiment after all, and in most scenarios, you don’t really notice the noise.
The Real Recording
Finally I had to pick a location for my first real recording beyond my backyard… I wanted somewhere that I figured would have sound sources happening in 360 degrees so that the surround channels were motivated. Given my laziness and wanting to stay local, I decided to record at my local grocery store parking lot. I recognized that I did not really have any clean recordings of this sort of location, so this test recording could actually become something I use on future projects: win-win!
So I drove over, deployed the rig with the LCR and LsRs blimps about 30″ apart, hopped back in my car, and prayed to the sound gods that no one would be bothered by my rather hideous mic setup standing in the planter. Thankfully I was able to record for 30 minutes without anyone questioning my intentinos.
I brought the recording back to the studio and gave it a listen… hey, it sounds pretty good! And no phase issues when I downmixed to stereo. I could see this playing in a scene quite nicely. I went through and trimmed out all the annoying bits that I didn’t want to hear in the finalized file. This included but was not limited to toddlers crying, curbside pickup loud plastic tray clattering, and intelligible conversations. By the end, I had a solid 14 minute 5.0 ambience; mission success! Feel free to download the file to hear it for yourself and use it on your future projects such as “Parking Lot Diaries: The Last Cart” starring Tom Cruise.
Final Thoughts
I was pleased with the overall sound of the recording and quite honestly surprised it didn’t sound like complete garbage since this was my first time recording an ambience with this many mics. The imaging of the sounds seem to translate pretty well as cars and shopping carts wheeled around. The rear channels fill in the back but aren’t too distracting. The major downside to this rig is the time it takes to set up and deploy (easily 20-30 minutes to put together at the studio and another 5-8 mins to deploy). But that’s coming from someone who is used to just working in stereo where I often just have a single blimp to worry about and adjust levels and placement for. Also, in terms of what true benefits this 5.0 recording has over a stereo recording is debatable. It is nice to “fill the bubble” of the sound field for a surround mix, but I personally tend to do that with multiple stereo recordings, which also allows for more separation between source material. With that said, I’m looking forward to trying out more traditional immersive mic arrays such as quad (4.0) and Double Mid-Side (5.0) to see how they compare to my janky experimental setup. But I don’t want to create another reason for buying more mics; I’ve already got so many!
Anyways, if you made it this far, I appreciate you going with me on this journey. It was really fun to re-ignite the sense of adventure with field recording by trying something new for a change, instead of just recording in stereo like I normally do.
May you have fun on your next recording adventure!
Cheers
Mike