[Wayne A. Pflughaupt]

I ended up moving the subwoofer to the center of the back wall where according to my folks, they were unable to localize the sound anymore and it did not sound "boomy" to them there.

I tried the right side of the room and also the left side like shown bellow after installing bass traps - the new 244 traps and prior to doing any new testing with REW more recently. It sounded excellent on the right side of the room but I was still able to localize it.

The closer I put it to a wall, the more I am able to localize bass there with the exception of placing it between my left tower and center channel as seen bellow. It sounded good there but I was able to localize higher frequency sounds there around the crossover.

Hopefully you’ve realized by now that you don’t have to rely on your ear to find the best location for your sub? REW can do that for you much more accurately. You don’t even really have to move the sub all around the room. You can plant it at the listening position and take the mic to prospective subwoofer locations. The REW reading will be the same as if you had the sub there and measured from the listening position.

Don’t worry about getting a REW reading that tracks the Target as close as possible. You’re looking for a location that will give the best extension with the fewest peaks and valleys, or one with peaks and valleys that can be easily equalized. As John noted, this will usually be at or near a corner. The Target in REW can easily be re-adjusted, as can your sub level, when it comes time to equalize with the BFD.

I would mostly like a second subwoofer to extend the low frequency which I understand is possible.

I do however want to have the 15Hz to 20Hz be a flat response also which would require a second subwoofer.

Adding a second subwoofer is no guarantee that you’ll get improved extension. Adding a second identical sub gets you the same extension as the first, only at a higher SPL level. Adding a second sub that’s either better or worse than the first will get you no improvement over what you had with the one (you’d want to go with the better new sub and ditch the older one). If you’re looking for sub-20 Hz extension and you aren’t getting it now, a change in subs is in order.

I think it makes more since to buy new speakers for the HT to match the sub, and move these to the new media room.

Any sub can be “matched” to any set of speakers. That is not an issue as it is say, with center-channel speakers vs. main L/R.

The problem I have is that boosting the subwoofer now causes problems because it becomes louder than my other speakers.

Well, yeah...

Regards,
Wayne