The previous post posed a vital question: how can a nature sound recordist avoid noisy field recordings? As we saw in that article, struggling with noise is as difficult as it is common.
George Vlad has travelled across Africa and Europe recording the sound of forests, deserts, wetlands, and more. He shares his field recordings on his blog and also in respected packaged sound libraries from his Mindful Audio website.
I have long admired George Vlad’s field recordings. I asked him if he would like to share his thoughts with us about struggling with noise while recording wildlife sounds. He kindly agreed. Today, George Vlad gives detailed insight on where noise comes from and how it emerges in nature recordings. He shares tips on how to reduce it. His thoughts also include many nature field recording tricks designed help everyone gather the clearest, most inspiring wildness soundscapes.
Creative Field Recording: What do you feel is the biggest factor that contributes to adding noise to nature recordings?
George Vlad: There probably isn’t one big factor that does that more so than others. With my recordings, I find that it’s a mix of several causes, for example:
- Unless I’m recording wind, I try to only record on very still days. Any breeze over 5 mph will make my recordings noisier by creating movement in trees, leaves, grass and even in the air itself.
- Humidity is also a big factor. High humidity will always dampen mid to high frequencies, which is where a lot of bird song sits. This will result in less than clean recordings unless you’re really close to sound sources.
- Temperature will alter sound propagation in complex ways. Probably the most drastic changes are caused by temperature inversion, which happens when the air is colder close to the ground and gets warmer higher above ground. This will in turn cause part of sound waves to bounce back towards the ground instead of dispersing in the atmosphere, effectively bringing noise from further away into your recordings.
- Sound source density, counter-intuitively, will make recordings seem more washed out and less present. When I traveled to a huge forest in the Carpathians I had trouble getting a crisp recording because there were so many birds! Their calls would bounce between trees and create a washed out cacophony instead of adding up to a “clean” soundscape. (I’m obviously not complaining about this from an ecology or conservation point of view, but rather acknowledging that it makes recording more difficult.) This became even more evident in the Danube Delta where there were frogs, insects and birds that do an insect-like chirping as well:
I still like these busy and chaotic recordings though.
- Another issue that many field recordists are not aware of is playing back ambiences at the wrong volume. If you’re recording really soft ambiences you should play them back at the same levels so that you don’t bring up noise artificially. Even with 24-bit recording, there will still be noise inherent to equipment, location and real world conditions.
- Composition: sound recording isn’t simply dropping a rig somewhere and pressing record. At the Wildlife Sound Recording Society meetings I’ve learnt to scout out locations prior to recording and to try and identify song posts from where birds would sing. This way I can think about composition and try to be place my mics relative to song perches where birds often sing from.
- Time of day, season. Songbirds generally sing a lot on spring dawns, but not so much on autumn nights for example. In Europe, certain birds like the Red-Breasted Robin sing throughout Winter as well. Places can sound dramatically different from season to season and from day to night, and if you want clean birdsong you might not always be able to record it.
- If the sound recordist is there with their rig, wildlife will generally shy away. Birds can easily hear, see or smell us even if we dress up in camo and try to be inconspicuous. This will result in the microphones only picking up distant calls and inherently higher noise levels.
Portable bird hides can work to some extent (as exemplified by my friend Pete Smith in this blog post). Burying gear in dirt or mud can also help disguise it. I prefer to leave my rig out for extended periods (more than 12 hours, ideally overnight) so that wildlife resumes its behaviors after I’ve been there.
- Location: it’s getting increasingly more difficult to find good locations for recording, both in the Western World and in places like Africa or South America. Plane noise is ubiquitous and can ruin excellent recordings. Combustion engines (in both vehicles and power generators) emit noise that travels huge distances. Farm animals like donkeys and roosters will do anything to ruin a recording! I don’t even try to record if I’m not sure I’m getting at least 10 minutes of uninterrupted “natural” soundscape.
CFR: What do you feel is the best way to avoid noise in nature recordings?
GV: Low noise microphones and preamps are required, especially for soft nature ambiences. Studio mics such as Schoeps might cause clicks, pops or stop working altogether in high humidity or extreme temperatures. I use Sennheiser RF microphones and have yet to experience this sort of problem, having recorded in temperatures ranging from way below freezing to scorching heat.
Furry wind protection should not be used unless it’s absolutely necessary. I find the Rycote Hi-Wind Cover much more useful since it does not dampen high frequencies as drastically as the so called dead-cats. This helps get a crisper recording with good air and presence.
Decent cables with connectors that don’t malfunction in high humidity, heat, snow, dust etc. are also required (even taped over if the circumstances call for it).
Long cables (100m or more) or recording rigs that can be left out for more than 12 hours at a time will work much better than sitting out with the microphones trying to be still. The latter requires excellent batteries and power efficiency plus large enough memory cards.
I find that I get better close-up recordings with small mics such as DPA 4060 lavs (without furry covers that might spook certain birds). They’re much easier to hide than a double mid-side rig, however I prefer the surround sound of the DMS for ambience recording.
If the signal to noise ratio isn’t good enough, you need to get closer to sound sources. This goes back to composition and the recordists’ aims and expectations.
Recording at the right time of day can make a huge difference. My favorite time to record is pre-dawn in spring, just as the first robins, blackbirds and wrens start singing. This is when there aren’t a lot of birds calling yet and I can get nice and crisp close-up calls if I’ve scouted the location properly. Once many individuals start singing it gets more difficult to get that “clean” sound that is so useful in sound design.
It never hurts to know a little (or a lot) about the species I’m targeting, their behaviour, when they sing, etc.
CFR: If a recording is noisy, do you treat the recording in any way while mastering (i.e., EQ, multi-band compression, etc)?
GV: I used to be more liberal with processing ambiences, performing noise reduction, multi-band compression, EQ, limiting etc. freely. Nowadays my aim is to get the “right” sound while recording and to fiddle with it in post as little as possible. Having said that, I still use FX like 50 to 80 Hz high-pass filters if there is no useful content in the low frequency register. On occasion I will also perform surgical spectral editing to replace an extraneous sound (rooster calling comes to mind) with background noise spliced from somewhere else in my recording.
CFR: Your Wetland Atmosphere library is particularly clean. Are there any recordings you particularly satisfied with their recording quality, or clarity?
GV: There are a few recordings in my libraries which I like the sound of, not necessarily because of their “cleanliness,” but rather for their composition. I like to have a strong central element (one or two birds singing) and a soft background made up by a few other birds singing, ideally of a different species. I also like contrast a lot, for example soft birdsong occasionally interspersed with raspy crow calls and woodpeckers drumming.
CFR: Do you have any quick tips for new recordists to record cleaner atmospheres, and also keep motivation high when dealing with this technical challenge?
GV: I think getting clean ambiences is a skill that can be honed and improved by doing it over and over. The other points I wrote about are a good starting point, but circumstances vary a lot and only by constantly being out in the field can a recordist get the ambiences they want.
Motivation is a completely different beast. For me it wasn’t a problem, since I love both being outdoors and recording. Even after the 100th noisy recording I still wanted to go back there and improve my skills. I can understand why others might feel demotivated though. I find that posting recordings in places like the Field Recording Facebook group is of great help. Contributing in community based libraries is also helpful since these usually have particular requirements.
My thanks to George Vlad for sharing his knowledge!
- Read George Vlad’s field recording blog.
- Visit his Mindful Audio Web shop.
- Follow him on Twitter.
- Listen to his sounds on SoundCloud.
- Visit the Facebook field recording group and the nature sound recording group.