One of the main goals of marine seismic acquisition is to deliver broadband data, rich in both low and high frequencies. The low frequencies are required for deep imaging, for inversion stability and for improved processing such as velocity analyses. The high frequencies are required, in addition to the low-frequencies, for better resolution. The problem of increasing the low-frequency content while maintaining the high-frequency content is caused by the well understood free-surface ghost effect. Towing streamers shallow favors the higher frequencies at the expense of attenuating the low frequencies, while towing streamers deep favors the lower frequencies, at the expense of attenuating frequencies within the seismic bandwidth.