Wiring a Studio: THE GROUND RULES
 
The Weighty Problems That Dog Our Daily Lives...

You would think that it would be possible to purchase a selection of audio equipment, a stack of leads, connect them together and everything would be fine.  Sadly, this is not the case!  These days, more than ever, a state of anarchy exists with audio standards.  There are different types of connectors used, different ways of wiring the same type of connector, different line levels, different metering standards, different types of balanced and unbalanced configurations and variations in the way equipment grounds are connected.

When trying to put together a studio, all kinds of incompatibility problems are encountered.  Loudness levels don't match when switching between audio sources.  Subtle distortion, loss of high frequency response and loss of headroom creeps in with inadequate line drivers connected to long lines and/or multiple inputs.  Crosstalk drives you crazy.  You get clicks, pops and interference.  Stray notes emanate from your sampler.  Above all, you get hums and buzzes everywhere you turn.

Manufacturers often confuse the issue by offering different solutions to counter these problems.  Often, people resign themselves to assuming that it is the nature of the equipment.  Sometimes it is possible to dramatically improve the performance and quietness of equipment by installing it correctly.  On the other hand, some problems are due to the internal design of some equipment and there is not much you can do about it.

Even if you go to the trouble of reading equipment manuals or talking to "audio consultants", chances are that you will get conflicting opinions and often a lot of voodoo!  It sometimes takes only one problem to ruin an entire installation.  Usually there is more than one problem in an installation and when one is fixed, it can sometimes make the overall picture appear worse.  This makes it extemely difficult to sort out an installation.

You need to work through the entire installation in detail and in a consistent manner, in order to get things working quietly and efficiently.

Now, read on...


Contents

  1. 1.  Audio Signals
    1. 1.1  Electrical Circuits
    2. 1.2  Audio Circuits
    3. 1.3  Balanced Audio Wiring
    4. 1.4  Unbalanced Audio Wiring
    5. 1.5  Pops, Hum and Crosstalk
  2. 2.  Electrostatic Interference
    1. 2.1  How Electrostatic Interference Works
    2. 2.2  Screening out Electrostatic Interference
      1. 2.2.1  Protecting Audio Signal Wiring against Electrostatic Interference
      2. 2.2.2  Protecting Audio Equipment against Electrostatic Interference
      3. 2.2.3  Protecting a Room from Electrostatic Interference
    3. 2.3  Grounding To reduce Electrostatic Interference
    4. 2.4  Sources of Electrostatic Interference
    5. 2.5  Electrostatic Interference Summary
  3. 3.  Electromagnetic Interference
    1. 3.1  Electromagnetic v Electrostatic Interference
    2. 3.2  How Electromagnetic Interference Works
    3. 3.3  Screening out Electromagnetic Interference
    4. 3.4  Sources of Electromagnetic Interference
    5. 3.5  Electromagnetic Interference Summary
  4. 4.  Common Path Interference
    1. 4.1  Common Path Interference in Ground Wiring
    2. 4.2  Grounding to reduce Common Path Interference
    3. 4.3  Grounding the Console
    4. 4.4  Is the Incoming Mains Ground Good Enough?
    5. 4.5  Should the Entire Studio be Wired on the Same Phase?
    6. 4.6  Common Path Interference in Unbalanced Wiring
    7. 4.7  Common Path Interference Summary
  5. 5.  Ground Loops
    1. 5.1  What is a Ground Loop?
    2. 5.2  How Ground Loops Work
  6. 6.  Unbalanced Wiring Systems
    1. 6.1  Ground Loops and Unbalanced Wiring Systems
    2. 6.2  Eliminating Ground Loops in Unbalanced Wiring Systems
    3. 6.3  Ground Lifting
    4. 6.4  Limitations of Unbalanced Configurations
  7. 7.  Balanced Wiring Systems
    1. 7.1  Coping with Ground Noise
      1. 7.1.1  Unbalanced Configurations
      2. 7.1.2  Balanced Configurations
    2. 7.2  Coping with Interference
    3. 7.3  Input Stage Types
      1. 7.3.1  Unbalanced
      2. 7.3.2  Electronically Balanced
      3. 7.3.3  Transformer Balanced
    4. 7.4  Output Stage Types
      1. 7.4.1  Unbalanced
      2. 7.4.2  Unbalanced, Ground Compensating
      3. 7.4.3  Electronically Balanced, Ground Referenced
      4. 7.4.4  Electronically Balanced, Floating
      5. 7.4.5  Transformer Balanced, Ground Referenced
      6. 7.4.6  Transformer Balanced, Floating
    5. 7.5  Input/Output Configuration Compatibility Chart
    6. 7.6  General Line Level Wiring
    7. 7.7  Microphone Wiring
    8. 7.8  Instrument Wiring
    9. 7.9  Studio Tie Lines
    10. 7.10  Inter-Control Room Tie Lines