Many nocmiggers simply place a portable sound recorder outside overnight, often achieving surprisingly good results. Some place them in buckets to try to reduce ambient noises (e.g. local Robin song!) and various techniques can be employed to weatherproof the recorder, from clingfilm covers to pillow cases.
There are many portable sound recorders on offer (see Jez riley French’s review from 2016) and there are several things to consider when selecting one. These include:
- Quality of in-built mics
- AC power option
- Ability to record .WAV files
- Port(s) for connecting external mics*
- Ability to accept SD card with min. 16GB of memory
*The default is a 3.5mm line-in jack. However, if you want to connect external mics that have XLR connectors (e.g. many shotgun mics) you’ll need a recorder with XLR ports.
Be wary of using cheap dicaphones, the sound quality of these often isn’t very good and the microphones are often poor quality too — they may be great value if you are just dabbling, but you will soon get frustrated by the poor quality sound they record.
Most, if not all, portable recorders will have a maximum sample rate of at least 44.1 kHz (the sampling rate of audio CDs, giving a 20 kHz maximum frequency – the highest frequency generally audible to humans. For more on sample rates, try the Audacity wiki). DVDs use 48kHz, so if you want to create DVD audio discs from your recordings, you may want to check for this option.
If you choose a portable sound recorder you will almost certainly need some way of muffling wind noise. There are many different wind mufflers on the market which go over your mics so look around online — the big hairy ones seem to work best, and also help a bit when it rains too. One thing you may want to try is focusing in the sounds you are recording. Many of try various large buckets or flower pots to do this — some are definitely better than others, but it is really what you can find available locally to you. Low level hum can be reduced by adding an old sheet to the base of the flower pot, but others have used bubble-wrap to do the same thing, or even egg-boxes. Waterproofing is also difficult. Clingflim over the top of your bucket/plant pot is one option, or and a small umbrella, but all options introduce some extra noise from things flapping around.
If you also want to use a portable sound recorder in the field and be ready for that single call of a fly-over Red-throated Pipit, it’ll need to be accessible! You may want to invest a few quid in a GoPro-type clip to attach it to your bins / scope / rucksack strap, then either record throughout the time you are in the field or have it set on pre-record (which captures the preceding 2–3 seconds of audio whenever you next press ‘Record’).