Want to know the physics side of this?
K here is how this works the colder the molecules are, the slower energy is transfered through them.
In effect when you see a wave going through water, even though it looks like it, you are not seeing one solid wave but millions of chains in a pattern.
A sound wave's energy has to go through matter (air molecules.) Every time the wave hits a molecule the molecule attempts to absorb the energy from the wave, but it can't so basically, a new wave is formed on the other side.
This process slows down the rate of the wave of energy and makes it dissipate faster the more air molecules there are.
This is absolutely 100% backed by science.
Currently,
even light has been slowed from 186,000 miles a second, down to 38 MPH!!!
guess how they did it?
They did it by shooting it through a cloud of molecules cooled to very close to absolute zero. Cold air is denser and slows down the transfer of energy.
HOWEVER, SPL is not perceived from the speed of energy, but the pressure of an environment a given distance from the source of energy... The dense environment then acts to create a higher pressure level within a certain proximity.
So here are some graphical charts to explain the difference between the effects of cold air and warm air systems, keep in mind these are exaggerated and highly estimated.
Notice That the cold air is initially louder than the hot air.
This is because the densely packed cold air provides more molecules to absorb the energy, which you perceive as "loudness."
However the densely packed molecules also absorb and diffuse the energy in the wave more quickly, making it slow down and weaken faster.
Edit this(^^^) does not take into account the effects of the temperature on the mechanics of a subwoofer, but i've never seen a sub turn into a block of ice so, did you spray them with water the night before?