I learned a long time ago to share my mistakes with others. It keeps me humble, and reaches two groups of people: Those more experienced than me who can help correct my errors, and those who might not have tread these waters before and who can learn from my experiences.
Which brings us to today’s post: recording ambiences using a pair of miniature omnidirectional microphones in boundary layer mounts. I learned a ton doing this, but the end results weren’t great. Today we’ll talk about what I accomplished and why it might not have worked out as well as I had hoped.
After my recent post on urban ambiences, I decided to record some fresh ambiences using a pair of DPA 4060 microphones using two techniques I hadn’t tried before: spaced-pair stereo and boundary-layer microphones.
Horse hair, water, mic, and wok lid. Now we're cookin'!
My last post featured teensy finger cymbals being dipped in water while resonating, recorded with a submerged hydrophone. This time we go a bit bigger.
Bowed cymbals are one of the classic clichéd horror movie sounds…clichéd because they’re awesome! (coincidentally, just yesterday, Chuck Russom posted some great examples on his blog.) I recorded some a while back, borrowing some cymbals from a friend at work who keeps his drum kit at work. During that session I also realized that the wok lid from my kitchen made similar sounds, but with a different timbre: More groany, throaty, less musical, but with a quality I liked.
So, I played the wok lid with a violin bow as I moved it into and out of a tub of water, again with the trusty Aquarian H2a-XLR hydrophone tracking to a Sound Devices 702. The H2a can be overly bright on some material, but for this stuff it was pretty good! (Next time I should record the above-water sound to a second channel with a small condenser mic for more mixing flexibility.)
The recording below is 100% unedited except for some slight compression and normalization.
[Aquarian H2a-XLR hydrophone into Sound Devices 702 recorder]
Hydrophone + Ice + Tonic. Sound and cocktail design in one easy step.
The latest addition to my microphone quiver is the Aquarian H2a-XLR hydrophone. For less than US$200, you get a really well-built unit with a high specific gravity (less sway in moving water) and a thin, flexible cable with an extremely supple “hand.”
I also got the rubber cup that enables it to be used as a contact microphone, and I must say that it also excels in this capacity: Super-low noise and very articulate, even recording human heartbeats with clarity (Hint: Aim for the sternum, the pecs have too much muscle and fat in the way). The H2a’s weight, however, prevents it from being easily taped upside-down or held in odd positions like my other contact mics I’ve used inpreviousposts.
I can’t hope to improve upon Darren Blondin’s excellent review of the Aquarian H2a, so in the short term, I’ll instead offer some quick and dirty recording results with it, with perhaps some more detailed results and analyses in the future. (Oh yes, some very strange recordings to come…)
When the H2a came in, I placed this device in all the usual places you’d expect for some quick tests: the sink, the bathtub, the cats’ water fountain. But having just discovered some very tasty tonic water for making cocktails, it struck me that I’d not recorded carbonation before. After hearing the clear, but not overly-bright, tones of the carbonation, I decided to mix up the room-temperature tonic water with some ice cubes.
The ice’s cracking, melting, and expansion was largely in the same frequency neighborhood as the carbonation bubbles and added an interesting dimension to the sound. Some initial sound processing makes me think that melting ice in still water might make for a cool creature sound pitched down -3 octaves or so, but for today, let’s listen to the original recording, unadorned and unprocessed.
[Aquarian H2a-XLR hydrophone into Sound Devices 702 recorder]
This wasn't the helicopter I recorded. This is just the only photo of a helicopter I've ever taken! (Shot on the Kaikoura Peninsula, South Island, New Zealand.)
Audio professionals may cringe when they hear this, but I always keep a microphone mounted in my windscreen/blimp/zeppelin, which is always on a short boom pole. No doubt I’ll pay the price when the little mic suspension’s rubber bands stretch and age prematurely, but I like to be prepared for those unexpected moments.
This paid off when I heard a helicopter over my house…much lower and louder than usual. I poked my head outside and could tell the pilot was going in very tight circles over my street. I grabbed my mic rig and my field recorder, and all I had to do was plug in, power up, and hit “Record.” Granted, I happened to have a stereo mic in my windscreen, which wouldn’t have been my ideal choice, but I’d rather use it rather than lose the recording! (Want a horribly embarrassing tale about losing a choice recording opportunity? Read the epilogue after this post’s sound recording.)
I don’t exactly live in a city center, so I’ve got both highway and bird noise polluting most of my backyard recordings. This time, though, the helicopter was so low that the highway was drowned out, and he circled enough times that I was able to do some splicing of the takes to eliminate most of the birdsong. EQ could remove the rest, but I didn’t want to lose the higher-frequency sizzle that I liked in the recording. I did some surgery to make it loop seamlessly, and the result is below.
Epilogue and cautionary tale: I was at a hut on the Kepler Track in New Zealand when a helicopter landed on a nearby pad to drop off some fellow trampers/hikers who were “heli-hiking.” I scrambled for the Zoom H2 in my pack. Through the headphones, the sound was loud, intense, perfectly overwhelming what tiny background noise there might have been. I listened to the chopper landing, idling, and taking off. And then I realized I was only monitoring the entire event, not actually recording. The H2 requires one press of the Record button to arm recording mode, and another press to actually get rolling (a common interface convention in most hand-held recorders). In the moment, I lost track of how many button presses I did, and my fuzzy windscreen prevented me from seeing the time -elapsed readout, which of course wasn’t moving. What is there to learn from this, besides that I’m a complete spastic loser?
Never assume anything. Triple check everything, even if you’re going to introduce handling noise or off-axis sound into the beginning of your recording. Better to have a shorter recording than none.
Gear that’s always in record mode when it’s on is good, gear that audibly gives you feedback when you’re rolling is better, and gear whose display isn’t concealed by necessary accessories is best.
(P.S. The title of this post refers not to what I saw, but the song “Unmarked Helicopters” by Soul Coughing, which has been playing in my head ever since I made this recording. Damn you, catchy melodies, damn yoooouuuu!)
New Zealand Cicada from the Queen Charlotte Track, South Island.
I’ve heard cicadas on three continents, and they all sound different. I remember in Thailand they sounded like a constant-tone fire or burglar alarm, the high-pitched ones you hear in modern office buildings. In New Zealand, they have more of an overlapping start-stop pattern with more distinct “crrrkk”-ing, rather than a constant drone. they’d only seem to really get loud when in direct sunlight. It took me a day to finally be able to spot them consistently, get a photo (above), and then finally find some spots with minimal birdsong to record them (although I included one bellbird call in the sample below just for fun).
This post also should serve as an example to other field recordists around how specifications do not a microphone make. The Zoom H2, while handy and theoretically able to capture sound up to 20kHz, really muddies high-frequency audio content. In person, these cicada sounds were rhythmic, pulsing, and you could even hear each individual start and stop their rhythms. In the final rendered audio – sure to be made worse by conversion to MP3 for Internet posting – feels flat, inarticulate, and less interesting than what my ears heard. One just can’t expect excellent frequency response from a $200 device. Still, once again, it’s what you have with you that counts, so at least one comes away with something.
It’s worth noting that Samon has the H4n’s frequency response graph on their website, but not the H2′s. (If the same capsules used in each unit, it’s interesting how a peaks above 5-8 KHz still doesn’t always translate into improved fidelity.)
Respected wireless manufacturer Lectrosonics tests the frequency characteristics of their hardware with what they call “The Dreaded Key Test.” This consists simply of jingling a keyring with a lot of keys in front of a mic, specifically to test the reproduction of high-frequency transients. I’d recommend that anyone evaluating a microphone do this test. If the recorded sounds are articulate and discrete, that’s a pretty darned good sign. Otherwise, this test will result in tones that are harsh, indistinct, and more like a blast of static. As many other folks will recommend: Rent gear you’re interested in before you buy it, if possible!
The Bogen Super Clamp held this OktavaMod MK012 right near the action.
I’ve posted before about photographic grip equipment for use in audio recording, but one little widget rises to the top of that list for me: the Bogen Super Clamp. While intended to position cameras and flashguns in unusual places without marring whatever it’s clamped to, the Super Clamp is super fun for audio, too.
Super Clamps come with a stud that locks into the clamp itself, and ends with a 1/4″-20 screw thread. All it takes is an adapter to change that to a more mic-mount-friendly 3/8″ or 5/8″ thread, and as long as everything’s screwed down tight, you can hang mics upside down, on the sides of vehicles, you name it. Combining them with other accessories like umbrella swivel adapters gives you even more mounting flexibility. The padding on their jaws also makes them pretty gentle on whatever you place them on. Just don’t overtighten them on surface that can’t take crushing pressure, like carbon fiber handlebars.
This mounting held pretty well on relatively gentle roads, and took 3 minutes to rig.
It’s large, bombproof, and heavy, so maybe it’s not something you might casually throw in your field recording bag. But if you want to position a mic somewhere that a mic stand can’t go, or shoot an unusual perspective, the Super Clamp can go there. I’ve used it to attach mics in all sorts of odd places. A great way to get some neat ideas is to watch this Chase Jarvis video, in which he uses Super Clamps and the Bogen Magic Arm to get unique point-of-view shots. Extrapolate by replacing the cameras with mics and it gets interesting.
There are other ways to get mics in weird places, too. The Super Clamp is not unique to Bogen: Matthews makes basically the same thing. There are many smaller jobbies, too, such as Cardellini Clamps, but they’re actually more expensive.
I’ll end this post with a sample of me riding around my street…not horribly exciting, but you’ll get the idea. The clip starts with pedaling uphill, then freewheeling on the flats, the disc brakes kicking in, and finally me clipping out of the pedals. The rumbling noises aren’t traffic, but rather the knobby tires rolling on the pavement.
As an avid photographer and aficionado of the Strobist school of lighting, I’ve got a mixture of modern, high-tech flashguns and some older ones I’ve picked up for cheap on Craigslist. Their age discrepancies don’t have any impact on how well they work…but my aging flash units sure sound strange.
After taking a shot with any flash, you hear almost always hear the flashgun’s capacitors recharging for the next shot. But my Nikon SB-26 (about 15 years old now) makes this warbling, incredibly”digital” sound. They sound like a 2400 baud modem that’s half asleep and dreaming, or a sweeping sample-start effect heard in glitch-centric music. The sound is incredibly soft and high-pitched, so only my large condenser mic has the sufficiently low noise floor to capture the sound without a lot of hiss.
Possibly useful for other recharging or power-up effects, some grimy and gritty digital process, or as part of a data-transmission sound effect..?
Full-Contact Audio: Contact microphones are cheap, fun, and beg for questionable uses.
There are Japanese beetle larvae living in my planter boxes. When we turn the soil, we sometimes unearth over a hundred at a time. We usually dig them out, leave them in a shallow bowl, and the local birds have a feast. I always wondered what disgusting critters that small sounded like, crawling around in a big ol’ pile.
This seemed like a job for contact microphones, the small little piezo elements that detect vibrations through objects rather than through the air. You can make your own for less than $5, but being a complete soldering nimrod, I ordered two hand-built, XLR-equipped and Plasti-Dipped contact microphones from Jeff Thompson at ContactMics.com. I jammed one of them into this slowly writhing mass. Totally gross. However, the sound was not at all as I had expected: crisp, brittle, and not that slimy. Since I’ve just recontextualized what this sound is, you’ll probably get all creeped out anyway. So enjoy. (Sorry about the ground loop hum, I was in a hurry and didn’t properly troubleshoot…)
If you read my take on the Fostex FR2-LE, I hope I left you with the impression that is has some incredible strengths, but some physical interface issues that just didn’t find ergonomically user friendly, and therefore not creatively enabling. I ultimately found refuge in the Sound Devices 702 digital field recorder.
Full Metal (Noise) Jockey: The Sound Devices 702 digital audio recorder.
Sound Devices has taken the world of production audio by storm with bulletproof products whose price, while higher than many consumer models, establishes a new value baseline. Professionals have far more advanced models than this: models with more tracks, time code, and such ( those who can spend 6 bills swear by the Cantar, for example). For me, this unit has hit a sweet spot.
HD Audio (24-bit, 192kHz)
Built to operate in intense heat and bitter cold
Amazing interface for such a complex device
The brightest LED’s I’ve ever seen anywhere
Ultra-flexible signal routing (mono, dual mono, XY stereo, or MS stereo)
Visual output concentrated on only one side
Richly tactile control knobs
All-metal construction
Recording to multiple cards or disks at once
Small (about the size of a hardcover book)!
I’m not sure what to say here that others haven’t alreadysaidelsewhere about this very impressive machine. But upgrading to this level of machine reminded me of several lessons that, despite my advancing years, I still don’t always learn.
Rent the nicer unit before buying the cheaper unit. I spent almost 50% of the cost of the 702 on other recording devices on my way towards it, and I should have rented all of these units, if possible, to really assess their usability characteristics. (On the other hand, the Zoom H2 is ultra-light and can be taken where the 702 can’t, and now I have a backup with the FR2-LE in my gear closet, so all three still do get use.)
Be bold with your research, specifically searching the name of the product you’re evaluating along with terms like “glitch,” “problem,” “error,” and even “catastrophic failure.” These little boxes are all expensive, objectively, so know what you’re getting into. Product and industry forums are your friend.
High price never means perfection. “High price” is subjective, and you can never assume that next level up will solve all your problems. Even the 702 has its quirks, often due to its inherent (usually beneficial) complexity.
At the end of the day, every device – from watches to cars – has its quirks and strengths. Just know what headaches you can live with and which ones will drive you crazy. A consumer’s self-knowledge is as important as feature sets. For me, the (very limited) caveats of the 702 don’t get in my way, which frees my mind to really focus on the recording.
Today’s audio clip is a 30-second snippet of some frogs in a riparian canyon not far from my home. It was an incredibly blustery day, hence the mid-high frequency hiss in the background. I hunched down as best as I could on a tiny dry patch in the middle of a stream. I had to sit for about five minutes for the frogs to start up again, being spooked by my presence. The frogs remained unseen, but one must have been right in front of my shotgun mic, pretty loud and clear.
[Røde NTG-2 mic, Sound Devices 702 field recorder]
The Fostex FR2-LE: superb value, challenging ergonomics in the field.
Ah, yes. This little minx of a box was so very enticing and lovely: 24-bit recording, 96kHz sample rate, two solid and quiet mic preamps, pre-record buffers, FireWire, stupid-proof record button mechanism…why didn’t my relationship with the Fostex FR2-LE work out in the long run?
Now, before we begin, don’t let me lead you astray: I loved the FR2-LE…for a while. Many, many people will love it as their one-and-only field recorder, and that’s awesome. It’s an insane value, especially if you get it (as I did) as a refurbished unit or one with cosmetic issues. For the price, you make some compromises – all plastic construction, noisy headphone amp – but in terms of pure value, seriously, nothing can touch it.
I upgraded from the Zoom H2 because the H2′s external-microphone preamp was noisier than a colic child at a wake. Trying to plugging decent mics into it to get a clean sound was a total non-starter. With the FR2-LE (doesn’t that just roll off the tongue?), there was so much to like. For its price class, I got the preamps I deserved – really clean, reasonably detailed. Good times.
My relationship began to sour once I really started getting into field recording in a serious way, and two things arose that were problematic. The first was its insane system of needing to format Compact Flash cards for either mono or stereo. Yes, you had to switch cards to go from mono to stereo. Talk about killing the moment.
But the other was the physical interface. Now’s a good time to remind my readers that I’m a professional interface designer, and I totally realize that price point and device complexity are huge constraints in designing a great user interface for a device as deep as this one. The FR2-LE’s biggest failing is its controls being laid out on two sidesof the device. This device is meant to be used while hanging around your neck; it has LED audio meters on the top, but they’re so pale as to be literally invisible in the daylight. If you want to see the much clearer LCD audio meters, they’re on the side (from your point of view with it around your neck). In order to see it without using another hand, you need to extend your belly, or use a knee, or some other kind of contortion. I’d need to drink a whole lot more beer to get enough of a gut to be able to see this data without A) using a second hand (uh, what if I’m holding a boompole?) or B) looking like a hunchback in need of a pee break. If Fostex fixed those top LED meters, I’d still be using this unit daily. I bought a signal mirror and gaffer-taped it to the inside of its case, just so I could see those controls without needing to angle the FR2-LE in just the right way.
Invectives aside, after about twenty excursions, I started to realize that this was going to drive me mad. This just wasn’t for me and how I wanted to work, ergonomically speaking. (Again, props to all who love the unit, such as Ric Viers of the Sound Effects Bible and many at the Nature Recordists group.) For now, it sits as a rainy-day backup unit in case my newer recorder needs servicing, or if I need two additional tracks for recording a tricky subject. What’s supplanted the FR2-LE in my daily recording? More on that in an upcoming post.
For this post’s audio clip, here are some cool groaning metal samples from a cow gate in the hills of western Marin County, California. Rusty and resonant, just how I like it!
