We're going to need a distinct look / theme
I am referring to logo (and possibly the same can be applied for the theme) which is derived by initials and that pattern is very common for many groups who are still in beta.
Suggesting some ideas for logo that signifies "signal processing at large" which is an example of most commonly used function called sinc function. Some samples i have added are as here: source: wiki. Alternatively, we can have a bit fancy version like (source) or (source). I have chosen sample images which are published under creative commons license. But we can construct something similar images as well.