Theoretical study on multi-level sources

This paper presents theoretical design principles for marine multi-level sources. The work is based on a modified Johnson model. Compared to a horizontal source, a multilevel source can be designed to improve low frequencies and reduce the ghost notch effect. Optimum depth and volume combinations exist in the design. However, there is also some flexibility which makes it possible to optimize in terms of the residual bubble oscillation. By considering both operational aspects and performance, we propose three or four levels in a multi-level source to be reasonable.