In 2004 we provided a PA system for Burton’s Biscuits in Edinburgh. Early in December 2021 we were back to bring the system up to date. But it wasn’t all plain sailing.
Back in July 2021, Stanley Security Solutions contacted us to come up with a design for a replacement system. The system had to replace a Whiteley Sigma 8000 mixer; which provided inputs for five microphones, a telephone interface, an AM/FM/DAB radio and time signals. The amplification being provided by a pair of QSC Audio ISA500Ti dual channel amplifiers (500W per channel).
Our proposed design replaced the Whiteley Sigma 8000 mixer with our go to audio router, ASL’s Vipedia-12-net. The two QSC ISA500 amplifiers were to be replaced by a pair of Crown CDi 4|300 amps. However, at the time of the system build they had a lead time of over 4 months. So we opted to use Cloud CA2500 amplifiers instead.
Install started on the 7th of December.
Installation – Day 1
Having first identified the system cables, functions and core colours we disconnected the old equipment rack and began the installation of the new equipment.
With the new system powered and its loudspeaker circuits connected it soon became clear we had an issue. One amplifier channel had shut down. Time to make some checks. Line impedance, ok, well within the amplifiers rated output. Resistance to earth, 5 Ohms! We needed a temporary fix. So, one of the old ISA500’s was pressed back into service. With its transformer isolated outputs it was far more tolerant of the earthy circuit.
With this issue resolved, for the time being, it was time to connect the microphones. The site has five microphones. Two being located in the factory to announce to the production areas. Two ‘All Call’ microphones for the reception and the gatehouse. And then there was the mystery fifth microphone. A mystery because no one onsite knew where was located.
At the end of the first day we had one of the factory microphones and the gatehouse microphone up and running; along with music playing and the shift time signals sounding.
Installation – Day 2
Day two began by connecting up the reception microphone cable. However, when it came to test the microphone it could not be located. This was resolved when we found out that the reception had been done away with many years ago. As a result the microphone cable was then disconnected.
Moving on. After connecting in the telephone interface we hit our second problem. It was faulty. When dialled, it would answer and allow you to record a message, however, when it accessed the PA system it would only broadcast a loud 50Hz mains hum. Not good. A replacement was needed.
The next to connect up was the second of the factory microphones. It too was faulty. However, during the previous day a box of old microphones had been unearthed from the back of a cupboard below the office stairs. Fortunately one of the microphones was found to be in good condition and worked.
The last cable to connect up was for the mysterious fifth microphone. Although no one knew where it was located it did appear to exist. Audio was present on the cable appearing as if the microphones press to talk switch was premenantly on. Due to the high level of signal on the cable it did not seem like line noise. Monitoring the audio seemed to suggest that the microphone was located somewhere within the factory area. Since it did not appear to be in use so, like with the reception microphone the cable was disconnected.
Commissioning – Day 3
Our last day on-site comprised of completing the system commissioning; adjusting the audio output levels and optimising the systems EQ to achive the best intelligibilty. and the audio levels and the system handover meeting.
Despite the issues we had with the installation, Stanleys client was pleased with our approach.
Jeff has been brilliant keeping us up to date on what’s happening…
Find out about our PA Systems here.
