CT Sounds is proud to introduce the hydro shallow mount subwoofer series after completing a rigorous R&D process spanning 2 years! Our goal was to engineer a 300-watt 8” shallow-mount subwoofer with a mounting depth below 3.5” that was suitable for both sealed & ported enclosures. To achieve this, we focused on the EBP (Efficiency Bandwidth Product). As a general rule, EBP < 50, is used only for sealed enclosures, EBP 50 - 100, is used for both, and EBP > 100, is used only for ported enclosures. EBP = FS/QES.

Our 1st prototype utilized a 50.8 mm voice coil & 30 oz magnet resulting in a high QES rating of 1.21 and low EBP of 39.23. The 2nd prototype utilized a 44.7 mm voice coil & 30 oz magnet resulting in a slightly lower QES rating of 0.976 and a slightly higher EBP of 48.64. After the 1st and 2nd prototypes, we determined a larger motor assembly was needed to provide a more controlled electrical system (lower QES). This led us to invest in a custom-tooled basket (used in the final prototype) to keep the mounting depth below 3.5”.

The 3rd and final prototype uses a 44.7 mm voice coil & 40 oz magnet resulting in a reduced QES rating of 0.668 and a balanced EBP of 71.06. In testing, we ran into mechanical noise due to the larger motor assembly and voice coil in a confined space. Therefore, we invested in a custom-tooled cone to maximize the excursion capability by creating an equal distance between the cone, spider, and bottom plate. The result is an 8” shallow-mount subwoofer that is extremely responsive in both sealed & ported enclosures.