Lavalier Microphone Techniques For Field Recording
Of all my microphones I probably use my lavaliers the most often. Whilst there are lots of good ones out there, like many recordists I invested in a pair of DPA 4060s. I find these tiny omnis to be pretty rugged microphones with crisp, balanced highs and extremely smooth, rounded lows. Since getting them I have been experimenting with various setups and recording techniques for stereo field recording.
The Coat Hanger
Back on my first ever recording trip to Iceland in 2013, it was environmental recordist Chris Watson who first taught me that you can simply mount lavaliers to each end of a coat hanger. This provides a wonderfully straightforward, lightweight and cheap mount for a spaced pair. The hook means that you can hang it up or bury it in the ground. I still use the coat hanger when carrying my equipment for long periods such as multi-day hikes and when weight is the biggest factor. However it does have its limits. You can’t attach it to a boom pole or stand and some environments simply have nowhere to hang a coat hanger. It also makes you look like a ufo hunter from a low budget sci-fi. This can definitely cause unwanted attention in populated environments!
Two DPAs recording sounds of the Camino de Santiago in Northern Spain, attached by coathanger
The Binaural Technique
Next I started using lavaliers for myaudiobooksas a binaural setup. The recordings with the DPAs were way clearer than the other purpose made binaural mics on the market. We found that we got the most realistic results from literally taping the microphone to the auricle (by the earhole) This produced some really nice 3D binaural spatial effects. However I wouldn’t recommend it for use outside of the studio (or with anyone else’s microphones for that matter).
The Quasi-Binaural Rig
For stealth recording outside of the studio I’ve often used a quasi-binaural setup. I took a cheap pair of sports earphones, removed the speakers and melted a small hole in each earphone, just big enough for the capsule of the lavaliers. From there I attach aBubblebee windshieldand tape the cable to keep it all in place. A readymade solution would be something likeBudFits. This technique allows you to record almost anywhere without anyone realising. I once managed to make a recording in the Panthéon, Paris, only for security to tell me I wasn’t allowed to listen to music!I still use this technique often as it requires the least amount of kit and is truly stealth. My biggest issue with this technique is that you capture every breath, every slight movement, even the sound of you gulping. To do a good job requires that you behave like a statue. Another drawback is that you can’t monitor your recording. I once did try bluetacking the lavaliers to the outside of a pair of normal earphones, but the results were not great. So in all some of the joy of recording is lost with this technique.
The Camera Arm Rig
Moving forward from the spaced pair coat hanger technique, I started usingColin Hunter’s setupfor any environmental recordings. The lavaliers are on two flexible camera arms, attached to a Rycote portable recorder suspension, which attaches to a stand. The suspension removes all handling noise, and having a stand means you can leave the mics out in the open at whatever height you please. The flexible arms also means you can adjust the distance of the spaced pair. Whats more you can fold them in, making for easier transportation. My hangups with this technique are that the camera arms are stiff to adjust and a bit flimsy. Its also not that compact and little heavy. I’m quite unorganised with cables so find myself getting tangled as well. Not to mention that you’ve now progressed to a high budget and frankly alarming ufo hunter – Definitely something to be avoided in public places. Colin has just worked out a V2 which uses the stubby Gorillapod arms instead and looks to be a much improved setup.
Recording a dawn chorus in the Pyrenees using dual camera arms to create a spaced pair
The Baffled Blimp
The blimp mounted technique is widely used with lavaliers. It might be just the right balance for compact spaced pair recording, especially in public places. Every time I’ve seen it used, its been in medium sized blimps, as distance between the two mics is vital to having a wide stereo image. However I only have the Rycote WS1. This is their smallest blimp and comes in at a total length of just 280mm. Whats more, the microphones would be mounted at the end cap intersection, leaving just 170mm between the mics. Whilst it comes down to taste, a typical AB pair will be spaced between 400mm and 600mm apart.
In order to improve channel separation I wanted to try using a baffle, or Jecklin disk between the two mics. The idea is to isolate the mics and block sound coming from the opposite side. The principles for a traditional Jecklin require an acoustically absorbent material be placed between the two mics, which should be 165mm apart, so ideal for me! However the disk should be around 3 times bigger than my blimp’s diameter. Whats more, Jecklin later revised his original specifications. He concluded an optimal distance to be a much wider 360mm apart. I was therefore uncertain as to how my setup would perform. For the disk I used Plastazote foam which at 28mm is a little thicker than the typical disk.
Unsure as how best to mount the mics I asked the Facebook Field Recording Group. It turns out everyone has their own method, from a wire strip of cut down coathanger that spans the length of the blimp to a wood dowel. My method is to simply use dental floss, which can be hooked around the end cap mounting clips. Not thick enough to block the caps, but strong enough to hold the mics with a little tape.
The result is a windproof, lightweight, clean and compact setup which can be handheld, boom or stand mounted. Plus it doesn’t make you look quite so crazy!
I used dental floss to suspend the microphones in the Rycote WS1 blimp. No handling noise!
The Blimp Test
Yesterday I took the rig out into the Toulousain sunshine to get an idea of how it sounded. Recoding train passes seemed a good subject as the left/right separation of a flypast is always revealing. Whilst I would have liked a second pair of DPAs to test it against, my only other field microphone to hand was the Rode NT4. The stereo mic has 2 cardioid capsules in an XY configuration. At least this would give some spatial comparison. The mics were aligned, with the Rode being just 50cm closer to the sound source. You can listen to the results (MP3) below.
Rode NT4 – Short Train
DPA 4060 – Short Train
Rode NT4 – Long Train
DPA 4060 – Long train
In listening back, the results between the two mics seem almost incomparable – I asked myself if I had high-passed the Rode by mistake, as the low frequency difference was enormous. Its clear that the DPAs do excel with this kind of bass-driven sound. The omnis also naturally sounded much, much wider than the Rode. In hindsight I should have set the Rode further back behind the DPAs. The real question was whether the stereo image would be as natural as the XY arrangement. At this point I must say I’m impressed, to me it really did sound natural. The disk seems to be adding a great deal of separation, despite it being on the small side. If anything I felt that the disk was doing too good a job. The sound attenuated very rapidly on the blocked side once the train passed. I’ll be using this technique whilst recording the French city of Toulouse over the coming months, so will update this post with further analysis in different recording environments.
Other Techniques for Lavaliers
There’s still several techniques I haven’t used much. One of the best things about lavaliers is just how tiny they are. It means that you can place them in all sorts of nooks and crannies that we usually couldn’t get to. They are often used in film sound on vehicles to close-mic the engine, or the inside of the cab. I read somewhere that they were buried in the desert on the Mad Max set and driven over! In an environmental setting you can hide them under rocks and leaves to get up close and personal with wildlife. There’s also surround sound which is a whole other topic on its own. I’ve already seen 4 channel blimp mounted 4060s for 4.0 playback, and DPA have their ownbaffled 5.1 solutionwhich is regularly used for live sports and pro game audio.
In all we can see just how useful lavs are for field recording. Inevitably the 4060’s self noise is higher than in many larger diaphragm mics, but for its price and sound quality (especially in the low end) its a tough one to beat. The lavs are a vital component of my field recording toolkit.
Whilst cycle touring I attached my DPAs using the coat hanger technique, leading to some interesting recordings!