What tools do you guys use to measure when a woofer is distorting, and what distortions do you measure.....
Originally Posted by maxmercy /forum/post/19510010
Use REW (new beta edition).
Use the RTA Function, set Mode to Spectrum, FFT Length to 131072, Averages to 4, Window to Hann.
Use the onboard tone generator in REW, fire up a sinewave. Set the THD calculator on (It'll open up a THD tab). Make sure the record button is on.
Increase the volume until you are around 5%-10% THD. Hear what it sounds like at different distortion levels and for different frequencies, set an audibility threshold for yourself (how much THD can you stand?). Make sure you have a voltmeter across the speaker terminals to monitor power going in, to make sure you don't fry the drivers. The difference between feeding a box 250W and 500W is only 3dB....
You'll be surprised what you'll tolerate down below 20Hz, where the harmonics are more easily heard than the main tone. Set for yourself a threshold, and see which box can get louder at a certain freq before reaching that threshold. The winner is the box that can go louder for the same THD down low, IMO.
I am quite interested to see the results....
BTW - I'd do this indoors v outdoors to see how much room gain you get....