Sample Photos—Paging System, Before and After
Here is a prime example of the technical challenges faced in a small community. The paging system for this rural factory was installed by the only technical resource in the area: the local independent telephone company (telco). Talk about winging it in a field they clearly were not properly trained in—this turned out to be a shopping list of all the things NOT to do with a paging system. Luckily for the our client, they had come to appreciate our technical expertise in all things related to communications and asked us to look into their paging issues.
FACILITY
The required paging levels varied tremendously throughout the complex of connected buildings. The photo below shows the most challenging of the areas, the primary factory floor with its vast size and high ambient noise near the plastic molding presses. At the opposite extreme were quiet warehouse storage areas that experienced only occasional temporary noise from fork lifts.
BEFORE
The client had multiple problems with the system as installed by their local telco:
- The paging volume was extremely uneven—too loud in some spots and inaudible in others due to poor speaker placement and distribution.
- Employees were frequently turning up the radio into the paging amplifier so that sports games or music drowned out important company voice pages.
- Some office areas experienced feedback squeal so that annoyed workers disconnected the paging system in their area.
- The client had recently experienced a severe tornado and so was especially concerned that emergency announcements be heard.
- The paging amplifier was so overloaded that it was literally too hot to touch. In fact, the amp had already failed at least twice, necessitating an expensive spare on perpetual standby.
TESTING
The situation called for a thorough scientific analysis. We made extensive technical measurements of sound pressure levels, system impedance, and various input and output voltage and power levels to determine loading and loss. We also measured distances from the amp to various speakers and checked against the heat capacity of the connecting wires.
AFTER
Analysis of our data enabled us to design and implement the following changes:
- We added loudspeakers throughout the facility, scientifically selected, installed, and adjusted to draw less power while providing more even distribution of sound.
- To further improve efficiency and eliminate overheating, we selected new wiring size and redesigned the connection topology.
- We established zones according to ambient noise levels, each with separate loudness controls and tap settings.
- We configured each zone with independent control of the entertainment source (radio) and paging announcements, including an automatic override which we custom engineered by coupling to the PBX in the computer/communications room to ensure audibility of announcements.
- We re-configured the radio antenna to minimize static noise caused by factory EMI, so that the radio signal was clearer to begin with and a lower sound level was acceptable.
- We even applied our experience with concert-type sound reinforcement systems to substitute that type of technology in the reverberant areas that had experienced feedback.
- As a final subjective test, we were pleased to note that—thanks to our engineered design, components, and installation—the paging amplifier was actually cool to the touch, despite driving twice as many loudspeakers!
directed per acoustic measurements
amp running cool despite more speakers