Subwoofer insight.


This is new territory to me. Current speakers are 2 way with frequency response of 60Hz-20KHz with +/- 2dB.  Sensitivity rated as 86dB. Chance to purchase a pair of REL 7 tis. I feel like I am missing something but will have to buy the subs to try out. My basic question is this. Does this purchase sound wise? I know what I am willing to spend but do you think I will notice an appreciable improvement.  I know that no one can listen through my ears but this is my first time doing this. Source is 75 watt integrated tube amp, McIntosh MA-2275. Thoughts appreciated. I am leaning towards going forward with the deal but would appreciate some feedback. Room is large and open, 28X38 feet with 9 foot ceilings. Thanks for any feedback.
ricmci
Make sure your room acoustics are dealt with first. They can make speakers sound larger than they did before, by tightening up the bass and controlling the mid/treble.  Talk to GIK acoustics.

That's first, next, subwoofers are great, but be prepared to take some effort to integrate them well.
With that large of room, Audio Kinesis Swarm is worth checking out.  Mcarbon used the same Audio Kinesis Dayton amp and built his own swarm from 4 unassembled box speakers from Dayton.  I used car audio sealed sub boxes and Kicker drivers.  Now trying find space for a 4th sub box, my room is much smaller than yours.  As gochurchgo mentioned 6 are even better for a large space.  I have a very good friend that sells car audio, hence my choice, and he insisted on letting me pay cost only.  2 years ago we built a Howe truss bridge across a creek on property he owns ten miles out of town in the woods.  
@ghosthouse
It sounds like you are using powered subs, but feeding them with a "speaker level signal from the amp" -- doesn't that cause overpowering of the sub?  I would think it also halves the impedance of each channel, which can be a challenge for the power amp.  Do the cables from each sub go directly to a pair (R or L) of power amp outputs, or to a pair of (R or L) speaker terminals? I wouldn't think it makes a difference, but I've learned not to trust my assumptions in this hobby.  

There are separate right and left 8 ohm taps on the integrated so seems okay for connection purposes.  Main speakers hooked to the 4 ohm taps. Super nice guy I dealt with today.  He gave me a couple of weeks to see if they work for me.  Now I just need to figure out how to get these jokers dialed in properly.  Thank you Eric for the room treatment advice. I recognize that the room size is somewhat of a problem.  I think the best I am going to be able to accomplish is maybe some local treatments around the equipment.  My wife is never going to allow anything hanging on wall.  I don't blame her.  It is as much as her house as mine.  I also appreciate Millercarbon advice on more subs but no way she is going to let cables run across her main living area.  Anyways, I got them hooked up without dialing in or proper positioning.  First impression is good.  Somewhat of guttural feeling or sensation.  Never listened through subs before so it is different indeed.  Need a little more time to get it as right as situation allows, watch some videos, read some discussions, etc on how to do it properly recognizing that there are limitations without professional room treatments and the like.  Any pointers (either personal or recommended videos or articles) from those who have similar experience as I am going though on how to properly dial them in would be appreciated.
Hi @cheeg -
The SB1000s offer good flexibility input wise. See the photo at the link here. They can accommodate speaker or line level input. I’m running 2 sets of speaker cable...one pair to the Forests, a second pair to the subs, both from the outputs of the integrated amp. Don’t know why speaker level input doesn’t overload the subs but it doesn’t.

When running a low power amp (e.g., First Watt F7) I can use output from the pre to line level input on the subs and then line level out from the subs into the power amp; only 1 pair of speaker cables from power amp to the Forests in this case. The fixed 80 Hz high pass filter in the subs will limit the low frequency signal the amp has to handle and lessen the load on it. Not an option with the integrated amp as I don’t have a separate pre-out on it.

I’m thinking because speaker level input impedance of the SB1000s is 2000 ohms the amp isn’t stressed.

https://www.svsound.com/products/sb-1000