Subwoofers with room correction built in?

redwood, room control is really speaker control. You are adjusting the speaker to suit room acoustics AT THE LISTENING POSITION. Everywhere else in the room the correction will be wrong. You still have to do your best to improve room acoustics. The Room control in subwoofers is extremely basic. It can only adjust frequency and phase. It can not correct group delays and most subwoofers have low pass filters only and not two way crossovers. These are two serious flaws if you are looking for the ultimate bass. Having said this a sub with room control is better than without and using two of them will be an improvement in most systems
The absolute best way of going about this is to get a DSP preamp like the MiniDSP , Anthem STR or DEQX Premate. Then build a passive sub from a kit. PartsExpress has a lot of them. Then get a commercial sound reinforcement amp with a high damping factor >500 and a lot of watts.
I like QSC products over Crown. With a system like this you have digital control over everything including the crossover. If electronics are so susceptible to vibration why would you want to put them inside a subwoofer?  

@mijostyn…+1,

Most often folks neglect the listening position altogether when going through the time and expense of setting up subs in the corner or alongside walls. It defeats the purpose for the ideal end state. 

I am close to that level of tweaking “get a DSP preamp, MiniDSP, etc.” except not building a passive sub with an external amp like you did. Perhaps, you can sell your DIY kits for the masses:)😀👍

@audioquest4life the elac EQ uses your smartphone mic, but directs you to take a nearfield and then a listening position recording by which to calculate the frequency curve. i’ve seen it demonstrated online and it seems pretty snappy. and yes, velodyne is a little under the radar, but they seem like they mean business with regards to subwoofers. they’ve been doing this built-in EQ for a while it seems.

@mijostyn

The absolute best way of going about this is to get a DSP preamp like the MiniDSP , Anthem STR or DEQX Premate

I have a great dac and preamp and don’t want to do the ADC and DAC through these alternate components for my full signal path. If it was just in the path between my preamp and sub, it would be more appealing. we’ll see how the elac’s EQ does by itself first, but I’m open to tweaks.  This is an interesting option from Underwood hifi by DSpeaker:  8033 SII subwoofer equalizer.  Just for the subwoofer.  

@bigwave thanks for the heads up about this brand, even though they're currently out of commission

Check out Herb R's review of the SVS 3000 MIcro in this month's Stereophile.  He spends a good deal of time on the phone app and the many variables that are constantly adjustable via the app.