Measure VAS and compare to spec, then model the driver in a cabinet and see how the model compared if you used measured values vs spec. Fs is higher in your measurement, but Qts is lower, you may find the cabinet models rather similarly, but VAS is required to determine that.
T/S parameter measurements haven't been standardized at a specific voltage, but are low voltage by definition as they are intended to be parameters of the speaker "at rest". What you will find is that Fs will shift as drive voltage is increased, but so will other parameters so the cabinet model will work out the same. It could be that Faital measures their drivers at 1V or 2V instead of the small signal (350mv?) you get from DATS.
Looking at the Faital datasheet, they spec Fs as 55Hz, but the impedance plot looks more like 58-59Hz, so they're stretching the numbers right from the get-go.
Just measure the VAS/Mms and model the driver before you decide that there's any issue with it. It'll take less than an hour and if you do it right there should be no worry of popping the cone out of the motor or destroying the spider
Temperature makes a big difference alright, it's easy to see a shift in Fs just by changing the ambient room temp by a couple degrees. You can see in your measurement above that you've worked Fs down some and Qms decreased from 16 to 12. What matters is how it affects the cabinet model, you'll need Vas and Mms for that. Had you measured all the parameters, you'd also see Vas increasing as you decrease Fs by breaking in the woofer due to the increased compliance.
Interesting to read Faital's reply regarding their suggested break in procedure. 23Vrms seems really high. I use a variac and a step down transformer to break in all my drivers (60 Hz). I know these are pro drivers but when I'm breaking in even large woofers, 8 - 12 volts is all that is required to drive them in free air to xmax or much more. By 14 volts they are really sounding distressed. 23Vrms into a 4 ohm load is 132 Watts. They must break in their drivers in a closed box instead of free air.
Comments
disappointing!
Measure VAS and compare to spec, then model the driver in a cabinet and see how the model compared if you used measured values vs spec. Fs is higher in your measurement, but Qts is lower, you may find the cabinet models rather similarly, but VAS is required to determine that.
T/S parameter measurements haven't been standardized at a specific voltage, but are low voltage by definition as they are intended to be parameters of the speaker "at rest". What you will find is that Fs will shift as drive voltage is increased, but so will other parameters so the cabinet model will work out the same. It could be that Faital measures their drivers at 1V or 2V instead of the small signal (350mv?) you get from DATS.
Looking at the Faital datasheet, they spec Fs as 55Hz, but the impedance plot looks more like 58-59Hz, so they're stretching the numbers right from the get-go.
Just measure the VAS/Mms and model the driver before you decide that there's any issue with it. It'll take less than an hour and if you do it right there should be no worry of popping the cone out of the motor or destroying the spider
Hmm...makes me wonder if the marketing dept nudged their own measured specs by 15%?
Temperature makes a big difference alright, it's easy to see a shift in Fs just by changing the ambient room temp by a couple degrees. You can see in your measurement above that you've worked Fs down some and Qms decreased from 16 to 12. What matters is how it affects the cabinet model, you'll need Vas and Mms for that. Had you measured all the parameters, you'd also see Vas increasing as you decrease Fs by breaking in the woofer due to the increased compliance.
Interesting to read Faital's reply regarding their suggested break in procedure. 23Vrms seems really high. I use a variac and a step down transformer to break in all my drivers (60 Hz). I know these are pro drivers but when I'm breaking in even large woofers, 8 - 12 volts is all that is required to drive them in free air to xmax or much more. By 14 volts they are really sounding distressed. 23Vrms into a 4 ohm load is 132 Watts. They must break in their drivers in a closed box instead of free air.