Noise Shaping Baffles for Motorcyles
<![CDATA[Face it, loud motorcycle pipes are so 90's.
Ideally we would shape the acoustic spectrum of the exhaust
noise so that most of the energy is in the lower frequencies.
This would allow other drivers to "sense" your presence and
just enough higher frequency energy so they can determine
your position.
I created a baffle that adds a rotational compentent to the
tradtional reflection and reduction techniques. It uses a
small section of 2" diameter copper pipe. I am trying to
determine if by adjusting the blades I can tune the noise
frequency. Also by having the exhaust gasses rotate, it may
create a more uniformly distributed pressure on the pipes
with less localized pressure spikes.
Problem encountered is I currently put the baffles too close to
the exit of the pipes. It did quiet the bike but it may be that
any shape would have done this. Also it is challenging to shape
a turbine by hand and the noise spectrum is a function of too
many parameters that are not in my control. I suspect to do
this properly you have to customize the pipes
(and their resonant frequency) in addition to the baffles. ]]>
See also
