Fohhn applies its science in NUS LT6
SINGAPORE: Ranked as Asia's top university in both the QS World University Rankings and the Times Higher Education World University Rankings in 2016, The National University of Singapore (NUS) is both the oldest and the largest university in the Lion State. When the Faculty of Engineering (FOE) was inaugurated in 1968, a demand for professional audio loudspeakers beyond cinema screens had been sparked by the electrification of 60’s rock music. The classrooms and lecture theatres of the day relied on the spoken word being delivered in a booming voice by lecturers. Fast forward half a century and Lecture Theatre 6 (LT6) now boasts a sound reinforcement system that allows the meekest of speakers to deliver perfect tones.
Located within the Faculty of Engineering, the A/V system of LT6 was recently upgraded by Swee Lee Holding. In terms of visuals, the 350-seat fan-shaped auditorium is now equipped with left-right and centre Epson 4K projectors and electric screens. In addition, the portable lecterns are outfitted with gooseneck microphones and document visualisers, together with full VGA, mic and video inputs. Although speech was stipulated as the main criteria for the new audio system, full range capabilities were required in order to cater for live performances, video and music playback that would in turn enhance venue flexibility.
Following a successful loudspeaker demonstration by Control Logic Systems, LT6 is now furnished with L-R Fohhn Linear Focus LFI220 wall-mounted column speakers augmented by L-R ceiling suspended XS30 subwoofers. Unobtrusive to the eye, the 2.20m high LTI220 aluminium extrusions measure 130mm wide x 120mm deep, yet incorporate 16 4-inch neodymium woofers. Each transducer is powered by an individual 100W Class-D amplifier allowing DSP settings including vertical dispersion monitoring, beam angle, acoustic focus, equalisation, internal delay, compression, limiting and presets. Whilst horizontal dispersion is fixed at 110°, the vertical sound inclination angles for all 16 woofers have been configured in 0.1° steps between -40° and +40°.
Fohhn’s Two-Beam Technology allows the speakers to generate two separate beams in their vertical dispersion range, providing simultaneous and focused coverage of different audience areas. Whilst the acoustic centres of both beams can be set anywhere from the top to the bottom of the column, the addition of side lobe free technology ensures that unwanted side lobes are suppressed resulting in a better directivity.
Operating within a frequency range of 60Hz to 17kHz, the two 15.0kg models have been fixed via M6 threads 2.5m above the floor to the left and right of the stage providing even coverage and powerful SPLs without feedback. Together with the electronic control of the speakers’ dispersion, even distribution is assured as the SPLs within the cylindrical wave decrease by 3dB, instead of 6dB, as the distance doubles. Musicality has been provided with the addition of two XS-30 single 15-inch active subwoofers extending the low frequencies down to 35Hz when required. Live audio is mixed on a Yamaha TL5 digital console in the rear control room.
By running Fohhn Audio Soft v4.0 software on a laptop, the NUS technicians can simply recall a saved audio setting depending on the programed event being hosted in LT6. The software allows access to the connected audio device presets and the Linea Focus simulation, whilst parameters such as operating status, time and temperature can also be controlled from the same GUI. Should it be required at any stage in future, Swee Lee Holding has the option to remote control and monitor the LT6 loudspeaker system via Fohhn Net. The green campus credentials are further enhanced by the LTI220’s ability to switch to standby mode when no signal is detected after a period of time. Whilst the FOE advance studies such as Bioengineering and Civil and Environmental Engineering, it wouldn’t be surprising if the German technical engineers from Fohhn were recalled to deliver a lecture of their own to demystify the science they have applied to LT6.