- Reducing Camcorder/DSLR "Hiss"

OBJECTIVE - OPTIMIZE SIGNAL-TO-NOISE RATIO (SNR)

You cannot eliminate noise from electronic recording equipment, such as digital audio recorders, camcorders, DSLR video cameras, etc.  The name of the game is to optimize the signal-to-noise ratio (SNR). 

SIGNAL - GET THE MICROPHONE CLOSE

This means that you want to get the signal level as high as possible by doing some obvious things, such as making sure you pay attention to microphone placement and get the microphone close to the speaker. 

DEALING WITH NOISY CAMERA AMPLIFIERS

However, camera amplifiers tend to be very noisy.  The way you get better signal-to-noise performance from noisy camera is to throttle back the noisy amplifiers in the camera, and replace the noisy gain with clean gain from a juicedLink low-noise preamplifier.

Throttling back the noisy amplifiers in the camera is easy enough to do with a camera which has manual control (always a recommended feature).  However, some cameras do not have manual control of their audio, and have what is known as an Automatic Gain Control (AGC) constantly operating.  The AGC circuit senses the incoming signal level, and adjusts its gain up for low signal levels, and down for high signal levels.  This is a convenient feature for instances when you are in an unpredictable signal level environment, where the AGC provides you with overload protection.  However, the AGC works against you when you are trying to get the best signal-to-noise performance from your equipment.  A selection of the juicedLink low-noise preamplifiers have an AGC Disable feature which will force the camera to throttle back its noisy amplifiers.  This is accomplished by sending a signal into the camera at a high level, then the AGC circuit senses the presence of a high signal level and then turns down its gain.

YOU NEED A PREAMPLIFIER ... PASSIVE-TYPE XLR ADAPTERS WILL NOT DO

It is important to note that throttling back the noisy camera amplifiers in is not sufficient to improve signal-to-noise ratio.  That alone thus reduce the noise, but it also reduces the microphone signal level as well.  The only way to improve the signal to noise ratio is to then boost up the microphone signal level going into the camera with the juicedLink low-noise preamplifier.  Passive-type XLR adapters from other manufacturers can not achieve improvement utilizing this technique.

LIMITATIONS: GARBAGE IN ... GARBAGE OUT

Additionally, it is also important to note that a low noise preamplifier can be used to improve poor signal-to-noise performance the downstream (i.e., the camera), but it can not improve or signal to noise performing components upstream (the microphone).  So, you need to use a microphone with decent signal to noise specifications, and the microphone needs to be boomed close to the speaker (no more than a foot in half away).  A poorly placed microphone or a microphone with poor signal to noise characteristics (typically, worse than 74dB SNR) will mask the improvement that the low noise preamplifier has provided you in improving the signal-to-noise performance of downstream camera.  So, garbage in … garbage out.