Soundman microphones in detail

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Whether you're recording your band's gig, or collecting street and environment sounds, the Soundman OKM microphones can help you capture every aspect of the experience. When you play an OKM recording through headphones, you'll feel like being there on location.

OKM microphones in the opened plastic pocket case. See more OKM pictures


The OKM stereo microphone set consists of a pair of miniature in-ear microphones designed for binaural recordings – ideal and discrete when recording in public places. Using computer matching, the pairs of microphones are carefully selected and in use the results are startling, generating very realistic spatial stereo imaging. The three OKM models provide good dynamic range, low noise and wide bandwidth. For critical work Soundman have made a "studio" version which boasts almost perfect channel match (less than 0.5dB difference) and excellent frequency response.

The microphones are stored in a compact, pocket-size plastic case complete with a couple of spare colour-coded foam capsule covers and a rotating cable tidy. The one-metre 'Y' lead connecting the ear pieces is terminated in a gold-plated 3.5mm TRS jack plug.

A3 adapter. See more OKM pictures

The power required by the omnidirectional electret microphones comes from the plug in power of a standard mic input or the optional A3 adapter, which can be connected to the line in of any portable recorder. The A3 powering adapter is a small plastic box which provides a greater powering voltage than is normally available from portable recorders, resulting in more headroom and a wider dynamic range. It also incorporates an amplifier to feed the signal to the line input of a recorder, which is usually much quieter than the microphone input. The A3 is powered by a 6V alkaline battery providing up to 100 hours of continuous operation. An optional Phantom Power Adapter is also available for plugging directly into a studio mixer or pre-amp.

Using OKM microphones

Both hands are free when using the OKM II, which makes it easier to adjust the recording levels and control your recording device. After some experience of using the OKM II and your preferred recording device your ears will become your monitors. You will soon know from what you hear what results you are going to get, producing excellent recordings in all sorts of conditions again and again and again.

Bass roll off and attenuation switches on the A3 adapter. See more OKM pictures

The A3 adaptor is highly recommended for use with the OKM II. It comes with some useful features: a bass roll off filter, a -20dB attenuation pad, and a battery tester. The A3 supplies the microphones with a 6V charge, increasing headroom significantly compared to the 1.5V supplied by most portable recorders. The interface can now be plugged into the microphone input or the line input, depending on sound pressure levels. This means a larger range of sound pressure levels can be recorded simply by changing the combination of input and the attenuator pad setting. Please see our quick guide to A3-adapter settings. Any unwanted low frequency background noise can be filtered away using the bass roll off filter.

The OKM can also be used as a boundary layer microphone or as a clip microphone. If required the microphones can be attached to a stereo bar, melon, tennis ball or football to name but a few of the methods already tried.

For a list of example applications and the most suitable OKM model for each please see the OKM application chart.

What is binaural recording?

Binaural techniques first used a dummy model of a head, with microphones fitted inside it, aiming to try and capture the sound we perceive. Soundman have developed on this method, by making the microphones small enough to fit in the ear. In binaural recording the head acts as a 'filter', resulting in what most people call a 'three-dimensional' feel in the recording. This spatial response is most evident when listening to the recordings using headphones, but can also create very interesting effects when played back over loudspeakers.