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Temperature And It's Effect On Db


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Looking at another thread there was a bit of debate on how temperature can change your scores.

For the sake of the argument, let's say that we're comparing a winter's day with temperatures around freezing versus a hot summer day.

Considerations I have thought of:

Air mass - cold air is more dense than hot air. Does this make much difference? Perhaps hot air is easier to 'flow' due to it's lower density.

Electrical efficiency - lower temperatures mean lower resistance in your cables, amps and voice coils, making them more efficient.

Chemical reactions - In particular the battery. Batteries make FAR less current when they're cold. This is probably the biggest and most measurable difference caused by temperatures. A battery with a CCA (CCA is measured at 15 degrees F I believe?) of 700A will probably do more like 1000A when it's warmer.

This leads to a pretty big difference in the power the amp makes.

So, what's everyone's thoughts on this? I'm guessing a lot of people will say it makes very little difference but look at the difference in horsepower from the engine of a top fuel drag car due to temperature changes - When you're pushing the limits of your equipment I bet it can make a reasonable difference.

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it makes a huge difference. a few other db drag people will agree with me. my system is louder on a 70 degree day than on a 90 degree. but, i have noticed that my voltage is alot better after my truck sits over night right now. last night is was 19 degrees where i am. when i started my truck up i let it warm up. my voltage gauge read 14.7 volts. in the summer i am lucky if i see any higher than 14.3 when my truck warms up.

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I've noticed that the cooler it is outside the better mine sounds, but then again I have always heard that heat is the enemy

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Heat plays a crucial role in alot of diffrent aspects of a vehicle or in SPL, to the Alts the subs, the amps and so on. As heat increases score decreases from what I have experienced in SPL Applications, for a Daily Pounder you will probally never hear or tell the diffrence.

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My numbers are always down when its cold and hot. I get my best numbers around 65 to 70. I have heard that cold weather lowers your freq. but going down in freq. has never worked for me.

The air can be too cold/dense and become harder to move with the same power. Atleast that is how a science professor explained it to me.

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it makes a huge difference. a few other db drag people will agree with me. my system is louder on a 70 degree day than on a 90 degree. but, i have noticed that my voltage is alot better after my truck sits over night right now. last night is was 19 degrees where i am. when i started my truck up i let it warm up. my voltage gauge read 14.7 volts. in the summer i am lucky if i see any higher than 14.3 when my truck warms up.

An alternator performs better when cold.

TeamSundown-3.jpgTeamNemesislogo.jpg

If you build it, db's will come...

NSPL World Record Holder Trunk 0-1800 watts---147.9 with 1722 clamped watts @ 40Hz(9-20-09).

Competition Only Record Holder Trunk 0-500 watts---148.1

2006 Nissan Altima 3.5 SE

Currently Rebuilding....

My 150db Plus Trunk Build

I do box designs.

[benH] 6:24 pm: clipping doesn't really hurt subs

[benH] 6:24 pm: being an idiot is what blows subs

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i know team riprock use a thermometer in there trooper because its loudest at a certain temperature

other buddy brought a portable air conditioner to keep the inside of his vehicle cold for a show that was hot as hell

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extreme cars like team Riprock are a whole different animal. The tolerances are so tight that any change in humidity or barometric pressure can effect frequency and score.

But in daily type cars its negligeable. You are more likely to see a decrease in score due to the effect of temperature on electrical system and equipment than any acoustical change, Just have to keep in mind to change your burp frequency to compensate.

my testing chart here says.

80 deg F cabin temp, 73 deg F enclosure temp. = 38hz, 153.4 dB

65 deg F cabin temp. 62 deg F enclosure temp. = 40hz, 153.4 dB

50 deg F cabin temp, 48 deg F enclosure temp. = 42hz. 153.4 dB

40 deg F cabin temp, 40 deg F enclosure temp. - 43hz. 153.4 dB

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