temperature speaker for measuring T/S parameters

[Ground Zero]

Hello

I have a question please, about the method to measure Thiele/Small parameters for my subwoofer..

It's seems the temperature is an important thing to consider.

To Mesure the parameters of my subwoofer i use the Dayton audio WT3

Dayton Audio - WT3 Woofer Tester

This seems very accurate because i have test it on a subwoofer ZEUZ DC12825IPMS "not hifonics sub" and the parameters are similar at 0.1 and this sub have a polypropylene cone.

but when i test my other subwoofer GZuw12x from ground zero audio i have for the FS parameters 37.8Hz with a temperature of 18°C but the problem is that this sub has a alu cone so it's cold otherwise other parameters are similar than the manual of the sub.

so can you tell me if it's normal ? or the constructor lie about this parameters, because on the manual it's a 28.9Hz and not 37.8

Can you tell me what temp must have the cone of the sub to have a good and accurate measurements please?

Thanks in advance

[Perry Babin]

Speakers are very complex (though they might not seem so). It's difficult to make speakers that consistently have the same parameters. Car woofers are probably the worst.

When using the T/S parameters, you're generally trying to predict the frequency response in an enclosure. The problem in a car is that the vehicle makes a bigger difference in the frequency response than the enclosure.

Often, the best option is to choose the manufacturer's recommended enclosure for the type of bass response you want and then use the bass controls (level, frequency...) and equalization to fine tune the response.

[Ground Zero]

Thanks Perry

I understand but i try with a hairdryer to heat the alu cone and fs down and is now similar to the thiele small manufacturer

so i can conclude that my sub is ok for a 50liters box and a vent 10cm diameter witch is 30cm of long

I do measurement because the manufacturer have 2 manuals for this sub and box are not the same it's why i prefer to do this before build the box to be sure it's the good box, in this case the largest cabinet against the smallest box of 32 liters