This month I had the opportunity to check out a product from Altec Lansing, the fullrange DS912-8A speaker cabinet. Over the history of audio, this company has led the way with a number of innovations.
A little bit of history: the engineers who, in 1936, formed Altec (All Technical Services Company), worked for Western Electric and developed the first speakers for cinema. This, as you may be aware, was the birth of amplification and sound systems, which now has developed into the multi-billion dollar business that it is today. Among the innovations were the first multi-cell highfrequency horn and the famous Voice of the Theater systems. Today the company has evolved into a corporation whose products have been used at the Olympics, airports, hotels, meeting venues, performance centers, convention facilities, and houses of worship.
The DS912-8A stands for Duplex Speaker, CD912 speaker component, 8-ohm, A Series.
This product is a five-sided speaker cabinet that houses a 12-inch cone and a 1.5-inch phenolic tweeter assembly in the Altec Lansing Duplex design. This Duplex (occasionally noted as coaxial) design is a mainstay of the philosophy behind the point source speakers from Altec Lansing. The speaker cabinet is based on their popular CD912-8B ceiling speaker, used in many meeting spaces and convention centers around the world.
The Duplex moniker was coined by Altec Lansing in 1941, when the company invented the first horn/speaker design. The theory behind the design was to provide a point source for sonic energy, thereby minimizing the associated problems with adjacent sound source cancellation and nulls in the audience area. The CD912 component was designed with houses of worship in mind: the coverage pattern is tightened to 75 degrees by 75 degrees at 2,000 Hz, the optimum speech intelligibility frequency. The coverage pattern at this frequency helps to project speech from a lectern or altar to the rear of the seating area.
I was pleasantly surprised to find this feature in the cabinet, as intelligibility did not diminish as I moved away from the speaker cabinet. I chose to listen to the cabinet in three mediums that are common in houses of worship: music, lavalier mics, and podium microphones. Using the system without EQ, I listened to a variety of classical and contemporary music. The musical quality of the cabinet lent itself to strings and vocal reproduction, while the same characteristics made the lavalier project nicely into the room.
When moving off axis from the front of the cabinet, the high frequencies spread smoothly to the corner of the highfrequency pattern, and I could hear a noticeable difference between the sound of the Duplex speaker and a constant directivity horn pattern common in many other loudspeakers. They have different characteristics in the reproduction of sound, depending on the application.
The DS912-8A is not meant to be arrayed in a tight pack together with other cabinets. The wide 90-degree-by-90-degree overall coverage pattern makes this cabinet right for a two or three box “exploded” installation to cover a fan-shaped audience area, common in many houses of worship today.
The Duplex design enables the speaker to be installed in a vertical or horizontal position. The horizontal position can save you space if you tuck the slanted side of the cabinet into a corner or soffit. A vertical installation is made possible via 12 different suspension points and using 3/8”-16 forged shoulder eyebolts. The sturdy steel cup on the bottom of the cabinet fits into a speaker stand when you want to use this as a portable speaker for gatherings, outdoor services, or youth activities.
The Altec Lansing difference was demonstrated when I opened the shipping box. On top was a Styrofoam piece holding the speaker into the box with all of the necessary pieces and parts for installation arranged in separate slots. Included in each box was the 3/8”-16 eyebolts ready for installation, a neutral color grill cloth for custom color matching, product literature, and an extra Altec name plate. This extra step makes it a little easier for the installer, which I appreciate because it is more a turnkey packaging solution.
The extra grill cloth was also a surprise to me, but one that made sense, especially if you were to choose a custom color for your speaker cabinet. Because many cabinets are painted during the installation process, you can dye the cloth to match the color of the cabinet instead of being stuck with a black grill cloth.
Removing the grill cloth was a lengthy process. Instead of just attaching the speaker grill with quick release tabs or Velcro, Altec designed the speaker grill as a more permanent part of the cabinet. You have to undo the screws on the side around the cabinet to release the frame, making it a secure covering for the grill.
In a typical installation of the product, the DS912-8A is combined with the LF115-8A subwoofer. I did not have a chance to listen to the cabinet with the subwoofer, however it will extend the frequency range below the 80 Hz of the full range cabinet. The full range cabinet hangs underneath the flown subwoofer using the forged eyebolts in a convenient configuration.
The reason I mention it here is that the sub has an internal passive crossover. You can run one speaker cable to the subwoofer and loop through the Neutrik connectors to connect the full-range cabinet. This only puts an 8-ohm load on one side of the amplifier, leaving the other side of the amp for fold-back monitors, front fill/choir fill, or the other side of a stereo PA.
These features mean that the cabinets in this series are a cost-effective solution for your house of worship. This is a strong selling point when working within a budget for an installation that does not need a speaker cluster. I would not recommend the speaker for loud environment or contemporary service where you had drums and bass pumping through the system; Altec makes larger loudspeakers that may be more appropriate for that application. But if your installation requires accurate, clear vocal or instrument reproduction, this is a speaker that you should listen to.
This speaker is also suitable for auditoriums or gymnasiums, where announcements and speeches take place. Altec Lansing also makes use of the EASE (Enhanced Acoustic Simulation for Engineers) platform of acoustical analysis, and will work with your designer on the proper array for your application, using EASE data as a guide for the system design.
In the right design and configuration, this cabinet is a good choice for your house of worship or auditorium. The wide dispersion and point source/Duplex design make this a smooth-sounding cabinet both onaxis and off. Finding the right speaker for your church can be difficult, but not if you consider using the correct cabinet for your installation. I would take the time to consider this cabinet, especially if you have spoken word and an acoustical music program to amplify in your house of worship.
Pete Tidemann is principal of Linear Velocity, an audio consulting
firm based in Minneapolis, MN. He can be reached at hans@linearvelocity.com.
