I received a call awhile back from my Director, Tim Coghill. Now, I haven’t worked for Tim in over 25 years, but he was, without reservation, the best director I’ve ever known. Period. I’d trust him to talk me through diffusing a roadside bomb.
Tim is the production manager at a SC ETV network station in Spartanburg, SC, and had just finished up a documentary for them. Until recently, PBS National had a requirement that all programs submitted to them must be mixed in 5.1 surround sound (they’ve backed off that requirement as of late).
What tim was asking me about was a simple way to capture 5.1 audio in the field. I know of lots of approaches to 5.1, but none of them could be called simple… other than mixing in plain old stereo and letting a 5.1 synthesizer do all the heavy lifting for you. I understand the newer ones do a pretty good job, too. But Tim was looking for another way, and even after 25 years, when Tim gives me a direction, that’s where I’m going.
I started ruminating on his idea of a simple, inexpensive method of capturing surround sound. I’ve come up with almost a solution. It’s far from perfect, but I figure it’s better than pocket lint.
At the core is the Zoom H4n. I’ve got one & use it a lot. I don’t love it, as it’s consumer-grade gear, and is loaded with compromises. But they’re small (it’s a handheld) battery powered (though it eats batteries like candy), and relatively cheap, about $300 street price. So far so good.
This little piggy has a pair of XLR inputs in addition to two onboard mics, and it has a 4-ch mode that allows you to record from both mics AND the XLRs. (Almost none of the commonly-available digital recorders can record more than two tracks at a time.) So you have a fairly cheap pseudo 4-track to work with. Six channels would be better, but let’s start with this.
Let’s imagine a single-person interview in a space with lots of background action… a deli, let’s say. You set your talent down and point the Zoom AWAY from your talent. The XLRs can be used to record a lav on one channel and a shotgun on the second channel.
The two tracks from the onboard mics are sent to the L/R rear channels. You’ll want to do some field testing to figure out which is the best way to orient the H4n… the soundfield might sound too extreme with the mics pointing away, and it may sound better if the mics face the talent, only placed some distance back.
The shotgun will likely pick up more “room” than the lav. Run the shotgun through a stereo generator and send that signal to the front left and right speakers and put the lav on the center channel. You’ll want to play around with this… the center channel might need a little shotgun, and the L/R fronts might need a little lav. But keep checking for phasing errors by summing everything to stereo and mono once and awhile to make sure you don’t get any really whacko-sounding phase cancellations. Some phasing will be unavoidable, but keep monitoring it just the same.
As you already know, the “.1” part of the 5.1 mix is the subwoofer. Pull these low frequencies wherever they sound best, perhaps the lav if you want to accentuate the speaker’s voice. Other sources might sound better if you want to accentuate the low frequency component of the environment… if you’re shooting on a battlefield, you’ll want those deep, rumbling explosions.
If you’re shooting two people on camera, then you’ll have to decide between two lavs, or a shotgun and a mixed lav signal, or just a shotgun and a single mic. Perhaps the single mic could get the rear signal, and use the zoom mics for the L/R fronts. You’ll need to experiment, and– here’s a crazy idea– use your ears and judgement.
The H4n is small enough that it can fit on a pole or a C-stand. Sometimes placing near a boundary surface, like a table, can give you a little boost as long as no one uses the table to shuffle scripts while you’re shooting. Camera noise will be an issue if you’re shooting a Red or an F900.
It’d be best if you did a dedicated stereo mix on a separate tape, and a 5.1 mix on another. This way you could avoid the whacko phase cancellations on your stereo mix, But rest assured, somebody somewhere will be listening to your 5.1 mix on only two speaker, so keep checking your mix folded down to stereo frequently.
This is about as close to a simple solution as I can come up with. One big drawback is the H4n records at 44.1/16 bit when it’s in 4ch mode. (I think it does, anyway… don’t have the manual in front of me at the moment.) This isn’t a broadcast standard, which unofficially has been decided should be 48K/24bit.
There are some more expensive and complex solutions that may be better… but I’m not sure if the degree of “better” would be worth the hassle. Zoom makes an R16 which I also have. It’s about the cheapest recorder that can record 8 tracks at the same time. And it can be run on battery power. But it too is limited to 44.1/16 when recording 8 channels at once (though I believe it has better specs when doing 4 channels), and the build quality leaves a lot to be desired. The benefit here is that you can use real mics for all 5 channels, and not depend on the recorder’s mics. (The recorder’s mics are OK… not bad, really, and very convenient… but I like having choices). Drawbacks are size, as the R16 is too big to fit in a bag, a more complex setup with five individual mics, and you may want a mixer for more control of the mics (but you’ll need one with direct outs, which is rare in small mixers… even good ones. The PSC Alphamix (recently discontinued, unfortunately, and hard to fund used), Sound Devices 442 (also recently discontinued, but widely available on the used market), and the current Sound Devices 552 are about the only small ones that I know for certain have direct outs. Audio Developments might. My Eela 191 doesn’t.)
My “real” 4-track would also be a better option for a recorder… an Edirol R4Pro, which has timecode and can record up to 96k, but it cost nearly $2k… not an inexpensive solution. Their R44 is a cheaper option at about a grand and is slightly smaller, but no timecode. They’re both too big for a bag, really.
Tascam has some new recorders out. The DR680 can supposedly record eight channels at once, but it has only 4 XLRs. The specifications are a little cryptic as well, as it has
six mic preamps and claims “up to 96kHz” BWAV. Does that mean it can record 96K with all eight channels going at once? Perhaps…but as I’ve discovered with my Zoom, perhaps not. But the price is right, $800 from B&H. Their HSP82 can do a full 8 tracks, but it’s a full $5k. For that much, though, a Sound Devices 788T is $6-7k and would probably be a better investment.
The A-list flagship recorders are Zaxcom’s Fusion at $8K, or their Deva 5.8/ Deva 16. Don’t get me started on the Fostex PD606, Sonosax SX-R4, or my favorite-though-I’ve-never-even-seen-a-real-one Nagra VI. (If any of these manufacturers would like me to
express a more authoritative opinion, they can send me one and I’ll be glad to handle it for them;-)
So there it is… at least a partial solution to the question of simple & inexpensive 5.1 capture. It’s isn’t perfect, but it is something to try, at least.
i think the perfect solution – especially for situations where there is need for a strong center as in film/video – is the so-called ‘double-mid side’ method and using only 3 microphones recording to only 3 discrete channels, you can in post create true 5.1 surround. compactness is also an attribute. and audio as good as it gets when using top end mics mike schoeps. glad to discuss more if interested-
Peter: Thanks very much for your comment. I’d seen a double MS setup in production photos, but wasn’t aware of the details. It looks to certainly be the best way to go, especially for a real production. The coolest rig that I’ve seen is on the Schoeps website. This probably wouldn’t work with the Zoom H4n without some modification/experimentation, though I’ve gotten some promising (though not really pro-grade) results using the external mic input jack on the back and a custom-built padded cable. Of course, using the Zoom H4n at all isn’t really pro-grade (in multichannel mode) because of the lower resolution, but I do like the small and lightweight form factor. I’ll write an update to this post as I learn more about it… I can’t wait to try this in the field! Thanks again, BG
no, it wouldn’t work with the zoom as the two channels of the zoom are restricted to the onboard mics, which among other things are ( i think ) restricted to an x/y pattern.
For a usual compact rig, you need: 1) a forward facing mic ( cardioid/hyper cardioid/shotgun) 2) a figure of eight mic, which is placed coincident, on top of it, in line with forward mic & with the null front & back, and taking sound from the side, and 3) a rear facing mic ideally placed all coincident to the front and side mics. There is a picture of this arrangement on my web site on the gear page (the blue schoeps in a field). You record these 3 mics, then matrix them in post.
If you are interested, glad to share more…
I’ll agree with you in part… it wouldn’t work on a feature film, or for any critical 5.1 application. But that wasn’t what we’re after here… time to think outside of the box a little. Tim asked me for a simple, inexpensive solution. Any proper 5.1 recording, including double mid-side, is none of these things. And I’ll repeat that the Zoom H4n is NOT the ideal recorder for this job, because of (among many other things) the low sample rate for multitrack recordings. But the Zoom’s onboard mics can be bypassed using the external mic in connector on the back. I’ve done it using a padded cable… I can record four iso tracks using this method.
The double mid-side technique is a truly elegant solution, and yours would definitely be the method of choice… if the time and budget allowed. But my point is it isn’t the only technique we can try. Double mid-side isn’t really inexpensive either, when you factor in the cost of the bidirectional mic, which needs to be high quality and fairly small.
My job as as a soundperson is to do what the client wants. Here is a situation where the client needs an alternative to traditional 5.1 recording. It IS NOT OPTIMAL, and I’ve said that several times. But it is an alternative that will give you at least some back-channel information, and it is about as simple and inexpensive and you can get.