Nexo unveiled its new GEO T touring sound system at the MusikMesse in Frankfurt last week. The system will also be on show at the NSCA Expo (National Systems Contractors Association) in Dallas, TX, later this week (March 13-15).
The new GEO T Tangent Array System was developed in conjunction with leading touring sound rental companies, and it has been successfully field tested by UK’s SSE Hire, on tour throughout Europe with Tori Amos; and by the Show Company in Singapore.
GEO T is designed for large venues and outdoor applications, engineered as a scalable system that can handle audiences from 1000 up to 100,000 or more. The series builds on Nexo’s experience gained from the development, testing and successful operation of the company’s first tangent array design, the GEO S.
“The larger-scale T Series was in mind from the outset,” explains Eric Vincenot, Nexo’s Technical Director. “The GEO T specification grew from the success of GEO S, which demonstrated that incredible results were achievable, providing that the physical rules were strictly obeyed. Software modelling showed that the penalties for even small compromises in design would be enormous; however, the no-compromise solution demanded extreme accuracy in construction of the cabinet and particularly the rigging system.”
The three key components of the GEO T line are the T4805 and T2820 full-range high-output loudspeakers, and the CD18 Controlled Directivity Subbass. The driver modules are complemented by newly-engineered flying hardware and GEOSoft Array Design Software for system configuration.
The GEO T4805 Vertical Tangent Array Module
Featuring a 2″ exit compression driver (HF), two front-firing 8″ long excursion neodymium cone drivers (MF/LF), and an additional pair of rear-firing 8″ long excursion neodymium cone drivers (LF only), the T4805 extends Nexo’s unique Controlled Directivity LF to the midbass region. The T4805 has a 5° HRW which allows variable curvature in a vertical coupling plane, adjustable in logarithmic steps from 0.125° to 5° with 0.01° precision. The system makes highly efficient use of amplifier power, with minimal cabling losses due to 32 Ohm impedance.
User Benefit: the GEO T4805 is a 3-way device which provides cardioid midbass using four long excursion high output neodymium 8″ cone drivers. Cardioid midbass improves control of long wavelengths in both the horizontal and vertical planes and allows shorter arrays to project low frequency energy as effectively as the higher frequencies. With Nexo’s NX241 digital controller generating a 90° x 90° cardioid pattern from 70 to 250 Hz, the T Series can control low frequencies with shorter lines than array modules based on horizontally spaced pairs of large-diaphragm cones.
The GEO T2820 Vertical/Horizontal Tangent Array Module
Featuring a 2” exit compression driver (HF) and two 8” long excursion neodymium cone drivers (MF). The T2820 has a HRW with a 20° curvature in a vertical or horizontal coupling plane, adjustable from 8° to 20°. The GEO T2820’s CDD™ (Configurable Directivity Device™) provides 120° dispersion in the non-coupling plane, enhancing its effectiveness as a downfill element in curved vertical tangent arrays.
User Benefit: The GEO HRW is the only dispersion control device that allows the array designer to vary the curvature of vertical arrays in inverse proportion to distance without compromising coherent coupling. This allows the imaging and definition to be as clear in the front rows as at the rear of the audience area.
The CD18 Subbass
The CD12 developed for the GEO S Series introduced Nexo’s unique Controlled Directivity Subbass. The new CD18 extends cardioid directional control to 31.5 Hz, thanks to its dual 18 inch woofers and the DSP algorithms of the Nexo NX241 digital controller. CD18s can be flown or stacked.
GEO T Flying Hardware
The GEO T system is very compact and lightweight compared to other high output line arrays. Designed from the start to be safe and easy to fly, the system incorporates Vertical Tangent Array top and bottom bumpers, which allow adjustment of the tilt angle and curvature of vertical tangent arrays using a two-motor chain hoist system. All GEO T hardware is designed and tested to maintain high load safety factors in curved vertical arrays, which introduce very high stress factors due to the change in angle from the vertical.
Innovative Design & Engineering
Innovative features of GEO technology, proven in the GEO S Series, are found in the new GEO T system, including:
- The Hyperboloid Reflective Wavesource (HRW™) uses an acoustical reflector derived through rigorous mathematical transformations. It has a real source (the compression driver) and a virtual source which can be located outside the enclosure. The virtual source can be made coincident with or tangent to another HRW, producing coherent coupling between multiple speakers, even when they have different dispersion angles. The coupling plane can be either horizontal or vertical, making GEO array modules suitable for both curved vertical arrays that deliver equal power to equal areas, or for horizontal arrays that deliver equal power to equal angles. Patent pending.
- The Directivity/Phase Device™ optimizes line source coupling between cone woofers in vertical tangent arrays. Long-throw 8 inch cones can handle low and mid frequencies with ease, but their acoustic centers are too far apart to couple as a line source at the crossover to the compression driver. The DPD™ divides the cone in two. This creates the equivalent of a closely spaced line of smaller drivers that couple as a line source at crossover, without compromising the low frequency output of the 8 inch driver. Patent pending.
- The CDD™ Configurable Directivity Device lets the user select the dispersion. GEO wavesources use a diffraction slot and exponential flare to control dispersion in the non-coupling plane. Patent pending.
On Tour With Tori Amos
SSE Audio Group has been field testing GEO T full-range and sub-bass units since the summer of 2002, with the complete system fulfilling its potential most recently at the larger venues on Tori Amos’ European tour. At Le Zenith in Paris, before a crowd of 7,000, the SSE team flew single arrays of seventeen T4805s on each side of the stage, with four CD18 sub-bass units. The system was entirely powered by Camco Vortex 6 digital amplifiers, with Nexo 241 digital processing.
“In use, GEO T opens up new ways to address complex acoustic problems,” says Chris Beale of SSE. “Reverberant rooms can be tamed, environmental issues solved and new microphone techniques explored with results that were hitherto unobtainable.”
“In R&D terms, Nexo has really pushed the boat out, and they’ve been brave both in the use of materials and the overall design. The result cannot be compared directly with other line array loudspeaker systems because it is not a line array in many physical respects. It is rather a truly tangent array-able composite device, designed and built with extreme precision to propagate the most accurate sound field you will have ever experienced. Of all the systems I’ve worked with, this is by far the most capable.”
