While using lavalier microphones clipped to clothing it’s always important to consider the type of fabric the mic is attached to and how prone to annoying rustling it will be. For news reports or studio based discussions it’s usually acceptable to have the microphones visible on clothing. In the case of a drama, a boom mic above the actors will often be preferable both from the point of view of getting the most natural, clean sound and because it’s out of frame and so doesn’t need to be cleverly concealed. However, sometimes the location or shot dictates that it simply isn’t practical or possible to use a boom and so there are times when radio mics needs to be used. In these cases the microphones have to be concealed from view, typically hidden under clothing.

Whenever a microphone is in contact with fabric there’s always a likelihood of some rustling when the subject moves around. Of course, careful mic placement can help to minimise this and a variety of different microphone mounts are available which can help to keep the fabric from making direct contact with the microphone. However, the fabric itself plays a major part in how much rustling you’ll end up with on the recording. I set out to test a variety of fabrics to find out which are the best and worst to attach lav microphones to.

How The Test Was Done

In order to carry out this test I used a Sennheiser EW100 radio mic transmitter and receiver along with the stock Sennheiser lavalier microphone capsule which is usually included with it. Although better capsules are available, this test was intended to evaluate different fabrics with an entry level lav mic as would often be used in lower budget video or TV productions. No post processing was done to the recordings other than some gain adjustment to match the average level between the various recordings. The following clothing and fabrics were tested:

• Cotton shirt

• Polyester coat

• Nylon coat

• Wool jumper

• Silk shirt

• Velvet jacket

• Polyester fleece

In each instance I wore the garment and attached the lavalier microphone to the front centre. I spoke a few lines while facing forwards so as not to go too off axis by turning my head. I gestured in a fairly animated way each time, doing my best to repeat the same movements consistently between recordings. These examples probably illustrate a greater than average amount of movement but nevertheless, they give a good comparison between the various fabrics and how prone they are to creating rustling noise. Take a listen to the examples below. There may be at least one result in there which surprises you!

Conclusion

I’ll leave it to you to make your own evaluations of these examples but I’d like to make a few points about the results. Firstly, some of the fabrics are pretty obvious ones to avoid. Attaching a lav mic to a polyester coat, for example, is asking for trouble. If you absolutely had to record someone wearing this type of fabric, a shotgun mic on a boom pole would be preferable if practical.

The wool jumper in the example was very heavy and I noted that it caused a reduction in the high frequency content of the recording. The microphone capsule was not obstructed but the wool nevertheless absorbed some of the top end. All of the fabrics had their own effect on the frequency response, creating a different tonal balance for each fabric. This would, of course, require some EQ in post but it’s useful to hear the differences in these raw recordings.

Cotton gave a very good result, with the least audible rustling in any of the examples. This was followed fairly closely by velvet.

Perhaps the biggest surprise in these examples, if you haven’t tried attaching a radio mic to it before, is silk. It does not go well with lav mics and causes a significant amount of rustling, even with fairly small amounts of movement. It’s almost as bad as a polyester coat!

One thing to take away from this is that whenever you’re planning a shoot, it’s a good idea to speak to the talent in advance and ask them to bring more than one outfit in case one proves to cause too much rustle with the microphone.

I’d be interested in hear your comments on the results of this test. Are there any other fabrics you’ve encountered which are a problem with lavalier microphones?

Image courtesy of RODE