Placement of subwoofers

IMO, you should try them at different locations and angles.  I have two subs and found the best sound (so far) by having one facing the same direction as the speaker and just to the outside of the speaker.  The other sub is at the outside of the other speaker but angled at about 60 degrees inward (toe in).  This removed the bloat in base that I was getting when them in the corners or facing forward for my listening positions.  Seems very room/furniture/equipment dependent.   It was a very noticeable change.  The big base sound is still there, but in the right amount.  

Place a subwoofer on your seat and walk around the room. This will reveal nodes and optimum placement

Appreciate the suggestions everyone. Very helpful! Below is the course of action that I am in the midst of carrying out based on the suggestions.

As I had removed most of my furniture from my living room to address this issue, I decided to get on my knees and do the subwoofer crawl (thanks @fstein ). I found the locations that I thought the bass sounded mildest (I am rather bass shy), and for now, have placed them on the right of the front wall (behind the speakers) and immediately behind my sitting position, against the back wall (thanks @avanti1960 ​​, @tablejockey , @12many ).  

Over the next couple of weeks, I will make minor adjustments to the location and gain of the subwoofers, in order to see what works best. Also, having done the subwoofer crawl, I now know the locations in my living room where the bass is most boomy and will try using bass traps to see what effect it has on the sound of my system (thanks @rick_n ). If all else fails, I will try the DSPeaker 8033 II as suggested by @kota1 .

Thanks everyone for the helpful suggestions!
 

I may be misunderstanding your response. 

[FYI Some manufactures offer Bluetooth or Wi-Fi connections as well as manufactures of decent quality custom length RCA or XLR cables available to bridge this new positioning.] 

You've placed one of your sub-bass speakers at the listening position and played a low frequency cadence of test tones through that sub and the main speakers while walking about the room? 

The priority is to map those areas where the bass energy is the loudest, ie. bass modes. It's not unusual for the next or lesser bass mode usually asymmetrical to the first. With the furniture out of the way map all the bass modes, everything else in the room is a null where low frequency is more difficult to achieve and control. 

With your sub-bass speakers positioned in the vicinity of these bass modes you'll be reducing the volume to your taste (shyness). You should hear an improvement in room loading and a more detailed low frequency presentation at the listening position using less gain. 

In my experience with your sub-bass speakers I found the addition of third party signal processing such as the DSPeaker to be very useful as have a majority of users making it a very questionable omission by manufactures.  

Despite the advantage of any signal processing, your sub-bass speakers remain a steep -6dB near the 30Hz region which usually limits extra low frequency output. Depending on your musical taste this may be a preferred non issue. 

All the best with your outcome.