Rumbler & Howler type systems into a smaller package? Bicycles

[Straypuft]

I have been thinking about how bicycles are getting more used, both pedal and electric type and sharing park/bike trails with walkers is a big thing, Issue is many people walking or running are wearing headphones which makes bells and electronic horns useless when a bike is coming up behind them.

Is it possible to see a low frequency device be made into a smaller rechargeable package to be used with a built in horn sound? It wouldnt need the penetrating power or range a Rumbler installed in a cruiser would need, just maybe around 150ft.

I can also see something in a small package being useful on EMS and police golf carts at large crowd events.

 

[shues]

If any of the two-inch subwoofers that have been brought to market recently are worth their salt, and given the energy density of lithium-ion battery technology, I imagine this is something that could be produced with relative ease.