Speck-electronics SSM User Manual download pdf (Page 60)

Chapter 5 Wiring and Other

If a patchbay is utilized in your mixing system, the rules for shielding

change. With a patchbay, normally all shields are connected at the

patchbay jacks, and not connected at the mixer or external audio

equipment.

The occurrence of EMI (Electro Magnetic Interference) and RFI

(Radio Frequency Interference) in a synth and sampler based system

should be of great concern and not overlooked when installing the

Model SSM. EMI is defined as any unwanted signal which adversely

affects the operation of the mixer or mixing system.

Stated simply, the undesirable effects of EMI may be perceived as a low

frequency smooth sounding 60Hz hum; a low frequency "edgy"

sounding 120Hz buzz; or a higher frequency "whine" caused by the

timing circuits in microprocessor based devices.

Almost every electronic device generates some amount of EMI

emissions. These emissions can be transmitted as electromagnetic

radiation or simply conducted though audio cables and power cords. In

the same respect, most electronic devices are also very susceptible to the

EMI emissions generated by other electronic devices.

There are natural and man made sources of EMI that you can't do

anything about. These sources include radio, TV, and radar transmitters,

as well as motors, lights, and computers. Even the Sun and atmospheric

conditions can be contributors to noise that you experience in your audio

system.

There are generally three elements that must be present for EMI to exist.

These include the source of the EMI (conducted or radiated), the

propagation medium by which EMI is transmitted (directly on the cables

or through the air), and the receptor that suffers the adverse affects of

EMI. If any of these three elements are eliminated or reduced, the EMI

interference will be eliminated or reduced.

The more electronic equipment operating within an equipment rack, the

higher the EMI emissions. The more audio cable and low level audio

equipment that exists within the same rack, the greater possibility of

unwanted noise. The result of EMI in an audio system manifests itself

as a buzz, hum, whine, or all three.

The most common EMI occurrence in an audio system is radiated

emissions from microprocessors in synths and samplers, and magnetic

field sources from transformers and power supplies.

EMI and RFI

Sources of EMI

Reducing EMI

1 2 ... 55 56 57 58 59 60 61

No comments

Speck-electronics SSM User Manual Page 60