Audio Field Recording Guide

How to Capture Everyday Sound Effects and Ambience Outdoors

Learn how audio location recording in typical outdoor locations can enhance home-made podcasts and video recordings.

Recording audio on location is a great way to document the essence of many urban spaces, add life to podcasts, and improve the quality of video recordings. Modern audio field recording gear is much cheaper, smaller and less obtrusive than before. This is an introduction on how to get good sound outdoors.

Recorder and Microphone Types

For urban field recording, a good choice is a small field recorder using memory cards of the same type as used in digital cameras. Something like a Zoom H2 is a good combination of stereo microphone and recorder all in one that fits in the palm of your hand. This gives you more than 2 hours of recording time on a 2GB SD card. Similar field recorders use Compact Flash cards.

Get closer to the Sound Source!

The first rule of audio field recording is to get close to the subject, particularly if it is dialogue. To record speech, the microphone should really be within a couple of meters of the speaker. Any further and the speech will become muddied by ambient noise; and particularly indoors, reflections off hard surfaces can make the speech indistinct if the microphone is much further away from the subject than the nearest wall.

Don’t hold the microphone

Do not let anyone hold your microphone. It turns vibrations into signals on your recording, and that includes the sound of the muscle tension in the hand. Use a tripod or stand to hold the microphone close to the subject; this will result in a better recording than if someone holds it.

Move away from unwanted noise

In an indoor setting, you can usually turn off unwanted noise sources like a radio or the air-conditioning. Outdoors you can’t usually do that, so you have to move away from noise sources and closer to your subject. The ear is very good at discriminating against extraneous noise, so you have to listen critically, not just for what you want to hear, but also to check there is not too much of what you don’t want to hear. Or record a section and listen to the playback – it is always better to get the cleanest original recording.

Wind noise is often a problem. Most field recorders come with a basic foam windshield – these are typically good for wind speeds up to about 5 mph. Any more and you will have problems with a rumbling sound in your recording – try and move to a less windy location or wait till it dies down. Alternatively, shield the mic with a ‘tent’ made of cloth like a T-shirt held on a wire frame.

Use the manual record level, not automatic

Automatic record level sounds a great idea, but it saps the life from a recording. In a typical city location, as soon as the talent stops talking, automatic record level winds up the levels, boosting things like traffic noise to the same level as the speaker’s voice. When the speaker starts again, the traffic noise is dropped, weakening the continuity of the recording. With digital recording, simply allow plenty of headroom and lift levels in editing.

Record uncompressed audio

Recording in a compressed format like mp3 or Windows Media reduces the quality of your recording, making it harder to filter and recompress without distortion.

Work within the limitations of your equipment

If you want to record wildlife sounds like birdsong or very quiet or very loud sounds you will need different techniques. The simple techniques described here will let you record audio for podcasts, photography, and videography under typical field conditions. If the audio will be synchronized to a video recording, a clapper board and spoken take number help match the recordings up.

Conclusion

These simple techniques will help you capture good audio from outdoor locations, for podcasting, video and documentary purposes.

How to Identify If Audio Equipment Is Grounded

Know if Hi-Fi Separates are Earthed or Ungrounded to Avoid Hum

Knowing whether there is a ground connection to Hi-Fi equipment can be useful when tracing ground loops and hum problems.

Is it worth being aware that mains-powered audio equipment comes in two main variants when it comes to tracing hum problems in domestic Hi-Fi systems? There is no performance difference – it is perfectly possible to make good sounding audio equipment which either has a mains ground connection or to make it without a ground connection.

However, using more than one item grounded to mains earth in a domestic audio system can lead to ground loops (also known as earth loops) which can lead to hum in the system. It is, therefore, necessary to identify whether Hi-Fi equipment is grounded or ungrounded.

How to Identify Audio Equipment that Does Not Have a Mains Ground (Earth) Connection

The easiest and most sure-fire way to identify a piece of ungrounded equipment is to look for a two-pin mains plug. A two-pin mains plug by definition has no earth connection, this piece of equipment will, therefore, be ungrounded.

In some countries such as the UK, nearly all mains plugs are three-pin, making this harder to see. For equipment with detachable mains cables, there is another plug in the system – the chassis-mounted plug on the equipment itself that the mains lead plugs into. If this is two-pin then the piece of equipment is ungrounded.

Other things to look for are a mains cable that has just two cores – these are often of a flat or oval cross-section rather than round cross-section. In the UK if the equipment is described as Class II or double-insulated it has no ground connection. Audio equipment that is powered from a wall-wart or plug-in power supply almost always does not have a mains ground, though there are some very rare exceptions.

How to Identify Audio Equipment that Has a Mains Ground (Earth) Connection

Unlike the infallible test for ungrounded equipment, it is not possible to conclusively state that a piece of equipment is grounded just because it has a three-pin power plug. However, if it is described as Class 1 insulated in the UK it is definitely grounded. Likewise, equipment that has a round cross-section non-detachable mains cable is likely to be grounded. The only way to know for sure is to perform a multimeter test.

How Electrical Safety Works in Grounded and Ungrounded Audio Equipment

There are two accepted ways of keeping people safe from mains power. One is to connect all exposed metal to the mains safety earth, which is carried on the third prong of the mains plug. The alternative, depending on the particular country electrical code, is to ensure that all mains power connections, live and neutral, are isolated by at least two insulating layers, one of which may be air. Such equipment may have just a two prong power cable.

How to Avoid Ground Loops in Hi Fi Equipment

Make sure that only one piece of equipment in the Hi Fi system is grounded – preferably the amplifier or control unit/pre-amplifier. If more than one piece of equipment is grounded, then plug the grounded components into the same distribution board or wall socket pair to minimize the ground loops and susceptibility to hum.

 

Secure Digital Memory Card (SD Memory Card)

The SD memory card is a special version of the MultiMediaCard. MultiMediaCards can also be used to store copyright-free content in devices with SD card slots. Starting in the 1st quarter of 2001, EMTEC will offer storage capacities of 32 and 64 megabytes. The SD memory cards cannot be read by the older MMC-compatible devices