What is a Coaxial speaker?
A coaxial speaker system is a system in which the individual driver units radiate the sound from the same point of axis. There are two main types. One is a compact design using two or three speaker drivers, usually 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 2- or 3-way loudspeakers. They include 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 which this type of design offers is the ability to use a smaller area, therefore are highly popularity in-car audio. Furthermore, the drives in the path of the low-frequency sound waves coming from the woofer do not reduce them.
Without time-alignment correction, the sound coming 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 were introducing a retail model next month. This was followed by designs from Sparkomatic, Clarion, Infinity, and others.
Professional application
When it comes to using coaxial loudspeakers in professional audio applications, coaxial loudspeakers 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 pattern of response is symmetric around the axis of the loudspeaker.
Concert usage
Coaxial loudspeakers have been used in concerts for on-stage foldback duties. This gives the musicians a more even sound field because of the single-source characteristic. 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. Clair Brothers, L-Acoustics, Radian Audio Engineering, RCF, Beyma, dB Technologies, Fulcrum Acoustic, and Rat Sound in partnership with Eastern Acoustic Works make other stage monitors using coaxial designs.
Source texts
https://books.google.rs/books?id=HgkEAAAAMBAJ&pg=PA37&redir_esc=y&fbclid=IwAR1Da7LSzs6aI-_nqWvzMrhibgoaXjxTshjCa3C6l9lnT3szwyWlT7oK11g#v=onepage&q&f=false
https://books.google.rs/books?id=K1t0GxyvVbMC&pg=PA92&redir_esc=y&fbclid=IwAR3z2q7gwVIrnebKIhZBf7truclbvpfGhE7xMAaYQc6_lZt8qtwjUf4sKvk#v=onepage&q&f=false
