Coaxial Speakers

What Is a Coaxial Speaker?

A coaxial speaker system is one in which the individual driver units radiate the sound from the same axis point. There are two main types. One compact design uses two or three speaker drivers and is usually used for in-car audio. The other is a two-way high-power design for professional audio, also known as single-source or dual-concentric loudspeakers.  

Coaxial Speaker Design

Coaxial speakers in cars are two or three-way loudspeakers. They include a tweeter, or the tweeter and mid-range driver. Moreover, their location is in front of the woofer, which, in this case, partially obscures it. The advantage this type of design offers is the ability to use a smaller area and, therefore, highly popular in-car audio. Furthermore, the drives in the path of the low-frequency sound waves from the woofer do not reduce them. Without time-alignment correction, the sound from the tweeter may arrive slightly before the sound from the woofer. This misalignment lacks addressing in automobile sound systems. This design became popular in the 1970s with Electronic Industries, Inc. of South Holland, Illinois. They introduced the general concept in May 1973, and Jensen Loudspeakers introduced a retail model in the next month. Designs from Sparkomatic, Clarion, Infinity, and others followed this.  

Professional Application

When using coaxial loudspeakers in professional audio applications, they enable sound from two drivers to come from one source. This characteristic allows a wider field of listening to a synchronized summation of speaker drivers than loudspeaker enclosures containing physically separated drivers. Also, the response pattern is symmetric around the axis of the loudspeaker.  

Concert Usage

Coaxial loudspeakers have been used in concerts for on-stage foldback duties. The single-source characteristics give the musicians a more even sound field. Additionally, the enclosure is more compact. McCune Sound in San Francisco used Altec 604s in a large proprietary stage wedge in the 1980s. At the same time, Professional Audio Systems (PAS), using Time Alignment technology from Ed Long, sold the popular SW series of compact stage wedges, offered with a 12 or 15-inch woofer and having a projecting high-frequency horn as in the 604. Eastern Acoustic Works, Clair Brothers, L-Acoustics, Radian Audio Engineering, RCF, Beyma, dB Technologies, Fulcrum Acoustic, and Rat Sound make other stage monitors using coaxial designs.