What sub under a grand?

It depends were you use it for, but these sub's are not that fast. I demo and compare subwoofers for timing and integration. On the other hand I want to use them till at least 120 hz. With Audyssey you can easily get a very good level of integration with a subwoofer. Above 80hz low freq. become physical. Beside this you get a more deep stage as well. In the pastI sold many rel subwoofers. We never went further than 70hz. These days some subwoofers use material and magnets so you can use them easily till 120hz or even higher. In all my tests this makes a big positive difference.

Well all I can say my rel t1 is a pooch! I have it set so low in order to avoid an extreme rattle a may as well not have it on, in fact i just turn it off while playing call of duty, watching movies and even with tv. so what good is this fast sub? with music it's ok, and that's all it is. i think the psa will be fine, if not i have a 30 day in home trial shipping free both way's. so what's to lose? do I think there are better subs? of course! am I going to pay 1500 +? nope! and this this t1 would fall apart at 120hz.

Claiming a "big positive difference" from using a sub for higher frequencies than around 50 to 60hz requires further explanation, and I hope there isn't anything of the sort forthcoming from the strange paragon of self parody that is Bo.

Yeah i'm not sure what you mean bo? But imo I think music should not only be heard but it should be felt. The best live concert I ever saw was in cedar rapids Iowa and the band was Tool 10,000 days tour,I was setting in the upper bowl straight back of the stage the bass response in this auditorium is unreal thumps your chest and rattles your seat, don't worry I could hear the pings and tings as well.my point is without this thunderous bass the concert would have been blah! this auditorium didn't use subs and amps that were just enough! they have more power and bigger drivers than what they need,just like most of our home setups.my main amp is way more than what I need my main speakers are more than what I need so why should my sub be less?

The idea's to use it higher than 80hz came from Audyssey. To be honest I never went higher than 80hz. So it was complete new for me. I thought it would not make a big difference. But I was wrong. The overall sound became more involving, stage depth became even bigger. Sharper individual focus of instruments and voices. I started at 120 hz, at the end I stopped at 140hz. The thing what is important that you need subwoofers with a fast response. This depends about the material use of a manufacturer. And also the magnet is important for the control as the amp which is used.

These days I set most subwoofers till 120hz of my clients. Audio always will be about quality and comparing. When I would have followed all rules in audio I would never be were I am now.Looking for a higher endresult in sound time and testing is needed.

Low freq. are very easy to be explained why they have such a big influence. When the freq. goes deeper, there will be more emotion. It is that simple. Ofcourse a concert without a deep low freq. is useless!