This depends upon your subject and the style of Parabolic Umbrella that you are using. A single speedlite paired with a 7' Silver Parabolic Umbrella will typically provide more output than a 7’ Diffusion or White Parabolic Umbrella. However, regardless of the umbrella style, a single speedlite is unlikely to provide the amount or spread of light you might want to light a large group or subject (i.e. car, motorcycle). We currently offer the Triple Threat Bracket, which is a simple solution for mounting multiple speedlites in an umbrella. We recommend this option for all photographers using large Parabolic Umbrellas.