  Despite extensive exploration of acoustic vortices carrying orbital angular
momentum (OAM), the generation of acoustic vortices with OAM orientations
beyond the conventional longitudinal direction remains largely unexplored.
Spatiotemporal (ST) vortices, featuring spiral phase twisting in the ST domain
and carrying transverse OAM, have recently attracted considerable interest in
optics and acoustics. Here, we report the generation of three-dimensional (3D)
ST acoustic vortices with arbitrarily oriented OAM, thereby opening up a new
dimension in acoustic OAM control. By utilizing a two-dimensional (2D) acoustic
phased array, we introduce two approaches to manipulate the orientation of OAM:
through the direct rotation of vortices in 3D space and the intersection of
vortices carrying distinct types of OAM. These methods enable unprecedented
control over the orientation of acoustic OAM, providing a new degree of freedom
in the manipulation of acoustic waves. The arbitrarily oriented OAM holds
promise for enhancing acoustic communication by broadening capacity and
enabling more complex particle manipulation techniques. Our work establishes a
foundation for future explorations into the complex dynamics of novel
structured acoustic fields in the ST domain.
