6 Microphone placement
In semi-planned situations, the environment will often dictate some of the choices a sound recordist may make, or at least will narrow down the options. For example, to record the dawn chorus, you would almost certainly have to rely on battery rather than mains power. Although a laptop can power a soundcard, which in turn can power microphones, this tends to drain batteries quite quickly and is quite cumbersome and fragile, so a typical choice for field recording is a dedicated battery-powered portable recording device. This may be anything from a sub-£100 Zoom to a professional-level Nagra or Sound Devices machine costing several thousand pounds. The more professional (and expensive) devices usually allow large capacity batteries to be attached, giving several hours of continuous recording time. However, less expensive devices often use less power, so two fully charged AA batteries can also provide enough power for a lot of recording. Since your portable device is likely to be small with few extra features, you should be able to get good battery life out of it. However, given the effort you will dedicate to any recording work, it is good practice to carry spare batteries with you, just in case.
The choice of recording device will also affect the selection of microphones. A professional device won’t have built-in microphones, and the expectation is that high-quality external microphones will therefore be used. Your device will almost certainly have built-in microphones but may also allow you to connect external microphones, either as an alternative, or as additional to the built-in ones. If you are using external microphones then you will have the chance to position them carefully before the birds start singing, and monitor the recording from a point further away.
If you choose to record a live concert, you won’t have much control over the timing of the event, and you won’t be able to get the performers to redo any sections if either you or they make a mistake, so you will have to be ready to go and get it right first time. If you are organised enough you should be able to set up before the sound-check or rehearsal and get an idea about the best position for your microphones or device and what levels to set while this is happening. Making recordings during rehearsals is a great way to learn how your device works in practice without the pressure of having to capture a one-off performance. Recording is a social practice, so the better the relationship you have with the performers, the better chance you will have of asking them to play a loud bit in rehearsal so that you can make sure you have made the right gain settings.
The visual element of any performance is always going to be important for the performers and the audience, so this will place limitations on where you can place your microphones. It is often the case that the most effective place for capturing the best sound simply isn’t accessible because of this reason, so you have to be ready to compromise. Given the presence of an audience, this should also make you think about microphone choice and positioning.
Take a moment to write a list of as many different kinds of noises that an audience may make.
Your list may include applause, cheering, coughing, sniffling, chair creaking, chatting, rustling or dropping programmes, glass clinking, children crying, and many other sounds. Some of these could be essential to include as part of your recording, but many other can detract from the end result.
Of the two main types of microphones – directional and omnidirectional – the most common choice for live recordings is directional, as this gives you at least some ability to focus more on the performance and less on the audience. This choice might not eliminate incidental noises, but it can reduce their amplitude relative to the performance, and it will still pick up applause very clearly.
Your device may not offer you any choice of microphones, in which case your main focus should be on deciding exactly where to place it in order to capture the right balance between each instrument and the space in which they are playing. This will almost always be somewhere along a line that passes through the centre of the space. If you place your device to one side, you will most likely end up with an unbalanced recording that has one channel quieter than the other or else contains more signal from the instruments on one side of the stage than the other.
In order to find the best distance for your device or microphones, you will have to experiment by making several recordings with your device at different distances from the sound source. It’s a good idea to try the extremes of distance first, and then, making careful notes, and taking photographs or maybe even using a tape measure, make more recordings with your mics at different locations. You will probably have to wait until you get home to be able to listen to these recordings properly, so making accurate notes is vital. In this way you should be able to build up a sense of how your device works best, but this will also give you great practical experience of how and why recorded music can sound so different.