Part 2: A Spotlight on Martin Audio’s MLA technology
The first part of our audio spotlight discussed how line array loudspeaker systems function in auditoriums in order to provide audiences with clear, high quality audio. We established how line arrays achieve directionality in concept, and then went a little deeper into how LF, MF and HF components of audio are treated by the individual drive units of each speaker in an array so as to ensure that all the frequency components of the emitted signal characteristically similar, finally moving on to ensuring that SPL is consistent from the front to the back of the audience.
All of this theory is great, but if it all worked perfectly in practise, why would speaker manufacturers and top audio professionals be working on ways to advance the technology? Martin Audio appears to be leading the way with their Multi-Cellular Line Array technology.
The first thing to note is that every venue has its own unique acoustic characteristics due to shape and size, meaning that set up is different for every room that a system is installed in, and ensuring that reverberance is minimised, clarity is maximised and a consistent SPL is maintained comes down to trial and error optimisation – using software to look at the results of one trial array after another – with speaker positioning, splay angles and rigging height. Optimising the system like this has been adequate for a long time, however the extensive preset libraries that are often used for different array configurations and venues are at best, near-fit approximations that cannot cater for all eventualities.
Martin Audio’s MLA technology has been designed with these issues in mind and attempts to tackle them with both array design and optimisation software, which may have started off solely for touring huge venues but has seen a serge into more corporate and smaller environments. The MLA Compact shares the sonic attributes of the larger model but is more likely to be used in a corporate environment due to several features.
As we know, traditional line array technology attempted to produce the same signal from all loudspeaker enclosures. More recent designs tend to be driven by 3 or 4 ‘stepped’ zones that treat the produced signal slightly differently. This treatment is essentially increased level and HF equalisation applied to the top of an array to compensate for air absorption losses with distance. An MLA is made up of up to 144 individually driven acoustics cells controlled and optimised by DSP software. Of the 144 cells in an array, 72 are HF cells and each of these is automatically optimised by the software in terms of level, phase and EQ, giving far greater control over HF frequency resolution. The loudspeaker enclosures are a 3-way all-horn loaded design, which ensures that low and mid frequencies keep up with the high efficiency HF section and the frequency response of the overall signal is smooth and void of acoustic discontinuities. In fact, having so many individually driven and optimised cells available increases the resolution of the entire array for the desired improvement in frequency response and SPL.
Unlike the array configuration software accompanying most line array systems, MLA’s Display 2.1 works in a reverse process. Rather than starting with speaker configurations and testing results, the software uses information on room design and audience positioning and numbers to calculate the acoustic source required to deliver a consistent frequency response and SPL. This process uses complex algorithms to give accurate predictions of the direct sound produced and generate accurate positional frequency responses and the best options for rigging the system, whilst taking into account any hard-avoid areas such as balconies. Display 2.1 interacts with the MLA’s on-board DSPs to deliver sound consistency and calculates the filter parameters for each speaker enclosure. Due to everything being under a computer’s control, the vertical coverage can be adjusted electronically to adapt to any environmental changes without needing to re-rig. Display 2.1 can be remotely controlled on tablets and PCs via VU-NET control software in a similar vein to other current control systems and the Power Factor Correction feature creates a greener audio source. Due to the whole system being networked, long, heavy gauge cables aren’t necessary, creating a neater environment and again, taking aesthetics and size of the venue into account.
Obviously there are a number of other solutions out there, but Martin Audio is certainly taking a lead in terms of bettering both the configuration process and the final output of systems. If you would like any further information on this product, or you are having any other audio problems, please contact us for a free site survey.