@T-Rex the biggest concern with porting as low as 10 Hertz would be first Port resonance. I haven’t modeled that, but my assumption is that first Port resonance is going to be within a frequency range that you’re probably going to be playing. You typically want that to be double where you’re crossing over. So if you decide that you want to play the subwoofer at 80 Hertz and below then you want your first Port resonance to be no lower than 160 HZ. Keep in mind as well that when we’re modeling and WinISD we’re getting what we call an anechoic measurement. This basically means it’s not taking the room into account at all. And with 20 Hertz and below those wavelengths are very long and any typical room will get a good amount of gain. Also keep in mind that there’s not a lot below 20 HZ in media. So typically tuning well below that isn’t necessary.
By the way, I completely agree that stereo integrity is typically a very good value subwoofer. Rarely do I say much about it, because in recent years he hasn’t been dedicated to it. It’s good to see that he had decided to make more. That had always been a DIY favorite.