Rhythm of Bones: the Seventh Echo

There is an extremely rare professional "tuner" in the world. They implant artificial bones to withstand the "reverberation" and complete the unfinished business for the deceased, thereby dissipating the sound skeleton. But the protagonist discovers that all the vocal remains that have been "transcended" by the tuner have not disappeared, but have been collected by some huge existence, and are being pieced together into an "ultimate symphony" that can shake the real world.