For your consideration, Garrett Park Guitars presents these Rotosound RS88LD Black Nylon Bass Guitar Strings

From the Rotosound website:

A string that was specifically designed by James How for Jim Burns’s famous Black Bison in 1962.

This string emulates the upright bass sound and the nearest you will ever get to a double bass that can be played as an electric bass.

The magnetic stainless steel undercovers that sit below the special black nylon tape ensures the best of both worlds by having a bass that is comfortable to handle, that will work with a conventional amplifier and yet offer a sound so reminiscent of its much larger brother.