Rack Layout Guidelines
In preparing rack layouts the designer may wish to consider the following guidelines:
1. Locate heavy items such as power supplies and amplifiers near the bottom for ease of installation and removal.
2. Locate items which receive a lot of operator attention, such as jackfields or signal processing, between the waist and eye level of the operator when he or she is in normal operating position.
3. Group together pieces of equipment which are related; for example, the paging and communications equipment in one rack, the switching and distribution equipment in another, and the effects and signal processing equipment in yet another, and so on.
4. Separate, when possible, signal equipment of different levels and types:
—Microphone level equipment
—RF (wireless microphone) equipment
—Line level equipment
—Control and power supply equipment
—Loudspeaker level equipment
—Video equipment
—Computer equipment
5. Leave space around equipment which is known to run hot—at least 1 rack unit above and below. Consider using a baffled vent panel above these units.
6. Avoid putting anything with controls on the front panels at the very bottom of the rack where they can be hit (with feet or brooms, for example).
7. Some amplifiers create strong electromagnetic fields around themselves, and sensitive equipment can have hum induced into its circuits if located immediately above or below. A spacing of 2 rack units is often sufficient.
8. Power amplifier racks that contain amplifiers which do not move air in or out of the rack, such as convection and side-to-side fan types, should have forced air cooling. (See Section 25.3 on cooling.)
9. Racks which have many items mounted on the rear rails deserve special attention, as this can restrict access to the rear of the front-mounted equipment, making wiring and service difficult. More racks may be required to reduce the density.
In practice one finds that in trying to meet all the above goals, conflicts will arise; for example, should all the signal processing for all the loudspeaker systems be together, or should the individual processing be located near the amplifiers they are driving, where it would form a logical grouping? The creative designer must ponder the advantages of the different approaches and may decide that, because the wiring is so much simpler one way than the other, the answer is clear!