Gain Adjustment Switch
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The SMX-30 has 3 gain settings.
-10 : Acts as a pad, reducing audio output level by 10dB. This setting is best to use when recording very
loud sounds so to avoid overdriving your camera’s audio input. The level reduction occurs before the
microphone’s gain stage so to protect against internal distortion as well.
0 : Disengages the gain adjustment and the output level is left unaffected.
+20 : Increases the audio output level by 20dB. This setting is best for recording very soft sounds or for
optimizing signal-to-noise ratio with DSLR cameras.
Optimizing Audio Gain With A Camera
Compact cameras such as DSLRs, camcorders and mirrorless cameras are notoriously equipped with
very low quality microphone preamps. Low quality preamps have an inherently high noise floor which
becomes very noticeable in the soundtrack of a video recording if the external microphone does not
provide enough gain. This noise manifests as low level “hiss” or “static” in the soundtrack of your video.
The SMX-30’s +20dB gain boost setting can help to alleviate this noise issue: by providing a much
hotter audio signal to your camera, you’ll be able to turn down the gain of your camera’s preamp and
thereby reduce the level of noise it produces. Even if your camera does not have a gain adjustment
setting, the boosted signal from the SMX-30 will still make noise less noticeable.
For best results, start by reducing your camera’s gain adjustment setting to as low a level as possible.
Set the SMX-30’s gain adjustment to +20dB and observe the audio meters on your camera. Gradually
increase the camera’s gain setting (it shouldn’t need much) until the audio level is optimal. Your audio
meters should be peaking slightly below the maximum limit so to reduce the possibility of distortion.
Keep in mind that the SMX-30 will work best when your camera’s Auto Gain Control function is turned
off. It’s always recommended that you record a test video with your settings to evaluate the quality of
the audio before recording anything important.
Windscreen
The SMX-30 comes with a custom-fitted foam windscreen that is removable. This windscreen is
designed to protect against light wind conditions when recording outdoors. The windscreen will also
provide adequate protection against plosive syllables when recording speech up close. The windscreen
can be removed for indoor use if desired but it is recommended to keep it on the microphone during
outdoor use.
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FIG. 7
