When Sound Solutions was contracted to replace the existing digital signal processors and speakers in June of 2020, we didn’t have access to the amplifier racks during our site survey, although they appeared to be in working condition. Once we commenced the installation in July, and the missing keys for the racks were found, we noted that several amplifiers were indeed defective. Some were displaying fault lights, and others were completely dead. Since the amplifiers had been powered on 24/7 for 28 years, we calculated that to be approximately 247,000 hours of run time, which obviously meant that the amps were beyond end of life.
We quickly got the approval to replace the amplifiers with new QSC networked amplifiers, which would communicate with the new QSC digital signal processor.
Seven QSC 4K4 amplifiers that put out 1000 watts per channel (each amplifier is a 4 channel model), replaced 34 two channel Peavey amps that put out 400 watts per channel. Given that we had redesigned the speaker system to use fewer speakers, we ended up with one spare amplifier channel, and vast amounts of newly available rack space.
The new QSC CX-Q4K4 forms part of the QSC Q-Sys audio network, so that each amplifier talks to the digital signal processor and touch screen via two redundant networks. Two networks are used in case there’s a glitch in one. In this case, the QSC amplifier automatically and silently switches to the backup network, without any loss in audio. The Q-Sys network provides many features not available in more traditional older analog audio amplifiers:
- digital signal processing within the amplifiers allows for fine tuning of the speaker system
- a digital switching amplifier is close to 90% efficient, compared to approximately 60% efficiency for the 1992 Peavey amplifiers
- significant monitoring of the amplifier parameters can be managed via the touch screen, a laptop computer, or remotely via the internet. Monitoring of amplifier health, current draw, power output, internal temperature and headroom can all be viewed even when not present at the amplifier racks.
- a significant reduction in power consumption when idling. Since the amplifiers are powered on 24/7, we noted the idle current draw of approximately 34 amps (1 amp draw per Peavey amplifier X 34 amps), was now reduced to 8 amps with the eight new four channel QSC amplifiers. The energy savings of the new sound system is substantial, and the heat generated by the new energy efficient amplifiers is noticeably less, especially in the main mixer/AV room.
- ability to expand the sound system to an almost infinite degree, as new amplifiers can simply be added to the network, as can additional inputs and outputs.
- less real estate used by the new amplifiers compared to the analog 1992 amps. The six 6’ amplifier racks used in the original installation were dedicated to the arena sound system. Had we started from scratch, the same system using 2020 QSC amplifiers and the DSP could have been installed into one 6’ rack. Less real estate needed by racks frees up space that can be used for other purposes.
The amplifier installation required 48 hours to complete, including removal all of the old amplifiers and installing the new ones, along with tuning and calibration.
Touch Screen Update with Pre-sets
Since the Sandman arena hosts a variety events, including the annual Watchtower gathering to hockey playoffs. We liaised with the City of Kamloops to ensure that the system was user friendly for everyone, including those people not proficient in running a complex sound system.
To simplify things, we provided a new page on the touch screen to reconfigure the sound system completely, including setting levels and speaker zones with the push of a button. These buttons are called ‘pre-sets’, and we’ve put 4 of them on the touch screen. Each pre-set can be programmed by unlocking the memory location with a password, setting the levels of each speaker zone to a user’s preference, then saving the settings to a pre-set. Pre-sets can then be recalled by the same user group with the push of one button, rather than having to set multiple volume controls and mute buttons. Different groups have their own pre-set buttons, to ensure there is no interference with other user’s settings.