Coherent perfect absorption can only be realized at specific resonant frequencies or in narrow bands, which greatly limits its usefulness in practical applications. In recent years, the introduction of non-Hermitian modulation and acoustic metamaterials has provided new research ideas for complex acoustic wave manipulation, and resulted in many novel wave-matter interactions that are difficult to realize in natural structures. In this paper, we propose a non-Hermitian acoustic subwavelength cavity-tube coupling model to theoretically derive and demonstrate the evolution of coherent perfect absorption. Coalescence of two coherent perfect absorptions with a bandwidth averaging factor of 12. 825 is realized by tuning the non-Hermitian parameters of the system, and the corresponding broadband perfect absorbing characteristics are observed on the output spectra. This work provides a new way to realize broadband coherent perfect absorption based on non-Hermitian acoustic metamaterials, and also lays a theoretical foundation for the development of new functional devices for broadband acoustic absorption, acoustic detection and other engineering applications.