To meet the current needs of events staging, a popular UK music venue opted for a full audio refurb. Paul Milligan reports.
Like many towns and cities across the UK, Cambridge is home to grassroots music venues which have always played a huge part in helping the big rock and pop stars of today hone their craft in front of a live audience when they were small and unknown. Cambridge Junction is the most famous music venue in the city, and in its history has played host to gigs from Coldplay, Radiohead, Green Day, Amy Winehouse, and Ed Sheeran.
Like many grassroots venues Cambridge Junction serves its local community by putting ona vast array of events, ranging from music to comedy to theatrical plays to art projects. It is also a social enterprise, earning over 50% of its income through events and activities which is reinvested back into the business and its social mission. Cambridge Junction’s first performance space was opened in 1990 on the site of the city’s former Cattle Market, with two further spaces added in 2005. J1 is the original and largest space with a capacity of 850 and features live music predominantly, J2 is a 220-capacity seated theatre and J3 is a smaller multipurpose space, suitable for rehearsals and presentations.
Because The Junction is home to a diverse array of entertainment this places a big demand on the technical infrastructure required to deliver them to audiences. It also has to compete with other entertainment venues in the local vicinity, so it’s essential that it can keep pace with the quality of delivery modern audiences expect and so the Junction, in partnership with Autograph Sound, has recently undergone a full revamp of the audio systems in its two main spaces.
Autograph has a long-standing relationship with the venue and the initial conversations it held were originally about replacing the mixing consoles. This conversation organically grew to one of a venue-wide upgrade project in which Autograph created an integrated system including consoles, loudspeaker systems, a venue-wide Dante network, stage racks and monitors.
Investment
What were the reasons driving the client to make an investment at that precise moment? “They needed to offer that rider friendliness they were lacking over recent years, with it being on a circuit for a certain size and capacity of gigs and events,” says Mark Noble, technical AV design engineer, Autograph Sound. “They were sold on the brand they already had (d&b audiotechnik) but the length of its lifespan meant it has served its purpose, and they had begun to substitute kit for hire kit to make visiting clients happy, and they weren’t necessarily meeting the demands of riders. In terms of a long-term sustainability plan, the client was continuously maintaining and repairing underperforming equipment, as it was failing because it was being driven too hard or had been overused for the purposes of today’s requirements.”
Two new DiGiCo Quantum 225 digital mixing consoles were supplied and installed by Autograph in J1. All associated hardware was designed into custom-made wheeled racks to allow equipment to be easily relocated throughout the venue as needed. “The Quantum 225’s were chosen because it was brand new, using some enhanced features familiar to visiting engineers, the client also wanted to ensure they were offering the latest technology to ensure it was making the best the long-term investment,” says Noble.
The 72-input channel capacity of the consoles is perfect for the venue’s requirements as engineers can convert or load their existing show files on to these consoles and be up and running quickly. “By installing DMI-Dante cards we integrated the consoles via the Dante network with direct control of the DQ Racks, so managing gain sharing between consoles and multi-track recordings is very simple. The matrix outputs from the FoH console feed the main PA system via Dante and d&b’s DS10 network bridge, so visiting engineers can bring their own DiGiCo show file complete with Waves plug-ins and be ready to work quickly with minimal changes,” adds Noble.
The choice of loudspeaker system for J1 was driven by several factors, one being the venue’s existing d&b inventory which had served them well for years (some of which has actually been repurposed). The size and shape of the room had provided some historical challenges, notably that the proximity of the main FoH loudspeakers to the stage had meant excessive on-stage bleed and thus the need for stage monitors to be excessively loud to compensate, which is a common problem in mid-sized venues.
Temperature rising
Getting the right audio for J1 was a tricky process, says Noble. “It’s a difficult shape acoustically because there’s lots of hexagonal walls and reflections and it has a shallow roof. You can pack about 700-800 people in there, but the energy has nowhere to go and the air starts to become very compressed and dense.” Noble goes on to explain how that effects the sound, “As temperature rises and humidity increases in the room it requires a PA system to cut through that with more filters to control the listening experience. Every waveform will travel at a different length from the loudspeaker, and that relies on how thin or how thick the air may be. In a room with 800 people, it can get 5C hotter, so the PA system is not going to be as clear or sharp as it was when we did a sound check where the room was empty and the humidity was lower.”
To do this Noble used d&b’s Array Processing tools. “Now they’ve got a small temperature and humidity sensor near the mixing console and they have features available within the software to adapt, so if the high frequency needs to push a bit further because of the humidity, it will just add a little boost to that part of the system,” Noble says.
The design created by Autograph for J1 includes eight d&b XSLi12 cabinets as main L&R, two V7P and one V10P for outfills and centre downfill and six KSL-GSUB subwoofers. The whole system is powered from eight d&b 40D amplifiers and uses a DS10 Audio Network Bridge to interface between the d&b amplifiers and the new Dante network. The existing loudspeaker infrastructure was retained and repurposed.
The KSL-GSUB subwoofers are configured as a sub array, allowing for a smoother low frequency response across the room than the previous arrangement. In addition, the low-frequency extension of the XSL means that the system can be driven either with KSL-GSUBS in two modes (standard or infra), which gives the venue more flexibility when it comes to hosting different genres of event, especially club nights.
What were the most difficult parts of the install for Autograph? “The short depth of the space but that has some width was a challenge. We were able to do a lot with software in 3D modelling before we even rigged the system but what the simulation doesn’t really give us an example of what happens with reflections from walls and absorptions from ventilation spaces above. That was really tricky to be able to predict. Which is why in the early phase of the tender process the decision was made for a line array system for J1, which was described as broadband directivity pattern. It means every frequency from that line array cabinet is now controllable down to a fixed coverage, rather than before where it was just the high frequencies up to a certain point. Now they’ve made this line array completely controllable which can reduce the noise behind the system.
We wanted to reduce the amount of energy on stage by having a cardioid line array as well as a cardioid sub-array system. That’s tricky when you are stood on stage and the PA is only two metres to your right and left. Having that broadband pattern control line array means we throw that energy in the right place, and we can reduce it in all the wrong places as much as possible,” explains Noble.
Another issue in J1 was that the layout has two bars at each side, “There were always complaints because the PA just went everywhere. You had people asking for drinks and the bar staff had to rely on hearing protection, which causes fatigue over long periods,” says Noble. “We looked at how we could improve the listening experience in those areas by controlling it so we could protect the staff. Now it’s significantly better, whilst the energy is very much in the room, it tapers off at the sides naturally, where you’d need it to, rather than someone having to blast the sound towards the back of the room because the main PA doesn’t cover properly.”
Again, this was achieved by using d&b’s Array Processing. “When you enable array processing over a calculation model, you can set parameters of how much your level drops, how much you would expect your level drop to be between the front listening point and the rear listening point, and when you apply the array processing its internal algorithm calculates that rigging fundamentals based on the layout of the room you’ve drawn - The height of the PA, the angles, the relationship between the quantity of cabinets. It smooths out the high frequency coverage, so each box is given its own filter set properties to coexist as more or less as a single source rather than multiple elements sort of firing down the room, and then you happen to do that manually.”
Over in J2
J2’s varied programme required a slightly different approach than J1 and the provision of a flexible auditorium audio system which can be reconfigured depending on the style of show. The room format can change from seated theatre to fully standing, for theatre, comedy and spoken word events through to live music and club nights. Autograph’s design here consists of a mixture of permanently-installed loudspeakers (d&b E8s driven by a single 30D amplifier) which cover the balconies and a portable stock which is used according to that specific event’s needs. This includes two V7P loudspeakers, four V-GSUBs and two more KSL-GSUBS, all driven by a pair of D40 amplifiers. All linked to the in-house Dante network via a DS10 Audio Network Bridge.
The final part of the upgrade was the provision of a portable stage monitor system that is used wherever required, which consists of 16 d&b MAX2 wedge monitors and D20 amplifiers, racked as one eight-channel and two four-channel systems for flexibility. The overall delivery, installation and commissioning was phased as the Junction had to continue as a busy working venue throughout, and was completed in summer 2023.
KIT LIST
d&b audiotechnik XSli12, Vi10p, Vi7p, V7p, E8 loudspeakers, KSL-GSUB, V-GSUB, B6 subwoofers, 40D, 30D, D40 amplifiers, DS10 network bridge, MAX2, M6 monitors
DiGoCo Quantum 225 mixing consoles, DQ-Rack, Dante DMI card, Waves DMI Card, Waves SoundGrid Extreme C Server
Klark Teknik DN32 Dante card for Midas M32
Netgear M4250 network proAV switches