Why does a sub play louder in warmer weather?

[xplod1236]

I noticed this recently. On a warm day, my rearview mirror was falling down, but on a cooler day, at the same volume, it didn't vibrate as much. Does the heat soften up the surround and spider, making the sub more efficient, or does it have something to do with air density?

[peranders]

How many dB's are we talking about here?

Never thought the affected object may have different properties at different temperatures

[xplod1236]

I haven't measured it, so I can't say for sure, but it was an easily noticeable difference. I'm guessing about 1-2 dB louder. And the temperature difference was about 20 deg. F (about 10 deg. C).

[chainenoble]

could be the mirror.the metal heats up and get more flexable.there could be a rubber gasket between the mirroe and the window that softens and loosens when heated

[xplod1236]

could be the mirror.

Could be, but I don't think it is. I could easily tell that the bass was louder.

[Relax]

Psycho-Acostics. You saw the mirror moving more do to the softer gasket and more pliable glue, and you assumed loudness. Your brain made it then sound louder to you. Maybe?

I don't think subs get louder in different temps, although I do know they get stiffer in cold. Part of the reason it sucks having a system in MN where I live. Blazing Hot in summer freezing cold in winter....

[Tehrasha]

Originally posted by xplod1236
but it was an easily noticeable difference. I'm guessing about 1-2 dB louder.

You need watch the weather forecasts, and wait for a very hot day with high humidity, while a high-pressure mass moves through your area. The air will be at its thickest and system should sound the loudest, yes?

You should easily get an extra .01dB out of the system.
You'll know it when you hear it.

Excuse me while I giggle for a while.

[xplod1236]

Originally posted by Relax
Psycho-Acostics. You saw the mirror moving more do to the softer gasket and more pliable glue, and you assumed loudness. Your brain made it then sound louder to you. Maybe?

Nope. The next day when it was cooler, I could also tell that it wasn't as loud as the day before.

I don't think subs get louder in different temps, although I do know they get stiffer in cold. Part of the reason it sucks having a system in MN where I live. Blazing Hot in summer freezing cold in winter....

Over here in Michigan, it's the same kind of weather. I did notice that a rubber surround gets stiffer in the cold, so that's why I guessed that it softened up in the heat.

Bending a soft piece of rubber is easier than bending a hard piece of rubber. So a soft surround would be easier to bend, resulting in more cone movement from the same VC force (what I said in my first post). Am I correct?

[Cyrus_s]

... Or the warmer weather is making your ear drums more pliable or not as pliable as mine in warm weather so it may sound glaringly different.

Anycase IMO there are way too many factors to list without proper testing.

Come to think of it, I have never seen some sort of test like this. Although one can use equations for the basic different densities of air with changing temps for basic ideas.

[tf1216]

I want to agree with xplod1236 that on hot days bass does seem to increase. This is probably a great question to ask the car audio professionals.

Here in NH the temperature changes considerably from the morning hours to the late afternoon. With my older subwoofers, I really felt like the bass impact/SPL was more after work than it was before.

I also think I remember reading something about this. Those particular subwoofers that I had were some type of aluminum cone. I think it is the effect the temperature has on the cone that changed the difference in sound.