I have basically been told this statement and want to make sure it is close to true?
A 40 hz tune in a 4th order is like tuning a ported box to 25 hz. If I tune my 4th to 45 hz, I should play well at 20-60hz depending on the woofer. My woofers have a low fs or around 28, so they should also play pretty low in a 4th order.
Does that sound about right? I assume this is why I very rarely see a 4th order tuned past 50 hz?