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EAW Issues White Paper on Concentric Summation Apertures

FOH Staff • News • June 24, 2020

WHITINSVILLE, MA – EAW announced a white paper on Concentric Summation Apertures (CSA), a simple yet sophisticated way to acoustically sum multiple transducers and bandpasses into a single apparent source. This reduces the overall size of the loudspeaker while simultaneously providing high SPL output, remarkably even coverage, and excellent intelligibility throughout the listening area.

More details from EAW (

CSA was patented by EAW in 2006 for use in the AX series. Since then it has been used in many EAW loudspeakers including KF720, KF740, Anya, Anna, and the new KF810P.


The KF810P is a three-way design utilizing four 5” mid frequency drivers and two 3” voice coil high frequency drivers. A key challenge for the designers was seamlessly combining these two frequency bands into a singular acoustic source. Arrival time differences between these 6 transducers would directly result in uneven coverage, harshness, and poor vocal intelligibility. CSA provided a perfect means to achieve the design goals and create a highly phase linear system.


CSA relies on the physics of how sound waves behave when passing through or across an 80% solid / 20% perforated surface. Sufficiently randomized apertures are ignored by high frequencies and the sound waves pass smoothly over them. Conversely, low frequency energy can pass through the apertures without disruption.

As seen above, the HF wave shown in green never “sees” more than 20% of its length perforated by the CSA apertures shown in yellow. The energy from the MF drivers below are able to emerge from the apertures and combine with the HF waves a to achieve near perfect transient response across the two bands.


Highly controlled and consistent coverage across the audible spectrum is a hallmark of all EAW designs. Coupled with EAW’s remaining 6 core technologies such as Adaptive performance CSA enables exceptional performance on the scale of high-performance concert level sound reinforcement. You can find a detailed white paper describing CSA technology at





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