Problem measuring resonant frequency, Please help! (1 Viewer)

[Ryan Leemhuis]

Last night I broke in a pair of Hi-Vi M6a's after having measured the resonance and it was much higher than the spec sheet. I broke them in for about 3 hours each and today the resonant frequency is still too high. I have tried two methods, both doing about the same thing. I measured for a peak in the voltage drop accross the woofer with a volt meter and then measured the frequency this occured at. I also hooked it up to a FFT analyzer and plotted Voltage vs. Freq. Both resulted in the same answer. For reference I am getting the value "58 Hz" when the spec sheet says 46 Hz. Any help is appeciated.

 

[Joe L.]

Do you get the same peak in response when you use an 8 ohm resistor instead of your sub-driver and measure the response across it. If you do, your amplifier might not be flat in its frequency response and as a result, your measurement is inaccurate.

Joe L.

 

[Dan Wesnor]

Getting Fs higher than the spec is not unusual, and happens about 95% of the time.