[Magialisk]

So I used to run "only" one SVS CS-Ultra but because of the size of my room (see attached Room Layout) and my craving for bass you can *feel* I'd always wanted to try adding a second one. A couple of weeks ago I found a guy locally selling his for a great price and snapped it up. This morning I finally had the opportunity to take a few hours and calibrate everything just right and I couldn't wait to share the results.

First, I should note that I set the tuning point on both subs to 12 Hz by plugging 2 ports. I used to run my single sub in the 16 Hz mode but now I have more output than I know what to do with and since I don't have a subsonic filter this seemed like the best thing to do. I also set the target level to 69dB when measuring an individual sub and 75dB when measuring the 2 together. I was able to realize most of the expected 6dB gain between the two measurements.

I've attached 4 images of my results with REW:
The first is a comparison of the response of both subs measured independently. The corner loaded sub is in green and *really* excites the 43 Hz room mode. It's 20dB above my target which should be ~4 times as loud!! It also seems to totally break down between 65 and 80 Hz..? The other sub in red had a very nice response IMO, just a few peaks to tame.

The second image is the measured response of the two subs together along with REW's prediction of the "corrected" response after I manually entered some filters. I subscribe to the fewer filters with larger bandwidths "minimal EQ" school of thought, so I used only 3 filters to take care of all the peaks. I also broke *the law* and added a 4dB boost to 20Hz to help pad that shortcoming. I may go back and take that out because psychologically it bothers me having a boost in there, but so far no bottoming or clipping during testing. The exact filters that I set can be seen in the 3rd image.

Finally the last image shows the measured response when it was all finished. Don't ask what happened around 13 Hz... All afternoon this would happen where a null would come and go in between measurements even though nothing else was changing. I'm inclined to blame it on the RS meter, as even with the .cal file loaded I suspect it's not very accurate below 15 Hz.

In the end, I'm thrilled with this result as it's flatter than I've been able to get before with just the one sub, with the added bonus of lower frequency extension. The amount of air being moved is incredible compared to just the one sub before, and so far no signs of bottoming. Everything I can think to test says that adding the 2nd sub was a hugely positive move.

Hopefully I didn't completely bore everyone, I just really wanted to share my results and maybe even get some feedback. Thanks for listening.