Begun in the mid-1980s and brought online a decade later, the Metro de Medellín is the circulatory system of Medellín, Colombia, the country’s second-largest metropolitan area. Serving a population of over 3 million, the system averages more than 400,000 riders each day across 20 miles of lines—two light rail and three aerial tramways (“cable cars”)—that have a combined 34 stations. The multi-modal system also incorporates a new Metro Plus system of bus lines that feature dedicated roadways and a planned total of 21 elevated-platform stations.
For paging and platform music at all stations, Metro de Medellín has created the world’s largest integrated NetMax networked matrix system, with 57 Electro-Voice N8000 matrix controllers. The system-wide installation also includes more than 250 Electro-Voice EVID series ceiling loudspeakers powered by more that 150 channels of Electro-Voice power amps. The paging system is also equipped with 163 Telex WP-300S dynamic wall plate microphones.
Metro de Medellín’s paging and public address system was designed by Medellín’s own Almacenes La Cita in conjunction with Ambientes Inteligentes of Medellin, Colombia, and installed by Indra Sistemas of Madrid, Spain. “We were looking for a solution that allowed all audio to be transported via IP and that would provide programmable DSP capabilities at each station so that we could make adjustments to tailor the system for each different situation,” says Gonzalo Lizarralde, Technical Solutions Manager for Metro de Medellín. “NetMax gave us exactly what we needed.”
Local and central control
In use from 3 a.m. until midnight each day, the system handles announcements generated locally by station personnel as well as announcements from the system’s central control point, which could be for the entire system, an individual line, or a single station. “The paging control platform for the subway is very well-structured and functional,” says Juan Montoya, Regional Sales Manager for Electro-Voice. “And it’s an easy-to-operate system for all of the line and station operators, who must keep their focus on functions other than the audio system.”
In addition to paging, the system distributes Metro Music programming that is put together by Metro de Medellín personnel. A priority scheme allows centrally generated announcements to override local announcements, which in turn override each station’s ambient music. The system is programmed to automatically boost sound output by up to 6 dB during heavy traffic hours to keep paging and music levels appropriate given increased ambient noise.
Music and those announcements that originate from central control are distributed via CobraNet and decoded locally by a CM-1 interface card in each N8000 300 MIPS digital matrix controller. Each N8000 is also equipped with an AO-1 8-channel analog output card as well as one or more MI-1 8-channel analog mic/line input cards.
For in-station sound reproduction the system includes 194 EVID C4.2 4-inch two-way coaxial ceiling loudspeakers and 58 EVID C8.2HC 8-inch pattern-control two-way coaxial ceiling loudspeakers. The loudspeakers are powered by 34 Electro-Voice PA4150L quad amplifiers that deliver 160 W per channel, as well as two CPS 8.5 8-channel amplifiers and one CPS 4.5 4-channel amplifier. Each CPS amplifier provides 500 W per channel and is equipped with an RCM-810 IRIS-Net remote control module.
The NetMax system is controlled by operators at the central control point via a user interface that allows visualization of the system as a whole and easy selection of the lines, stations, or other locations to which a given announcement is to be delivered. “A big bonus for us is how easy the user interface makes it to program and use the system,” Lizarralde says. “We’re also very happy with the scalability of the NetMax solution, because the Metro is an ongoing project that will continue to expand more and more. Not only are we very pleased with the overall operation of the EV system, if we analyze it from a cost and benefits angle, we’re even more satisfied.”