Snbeall - I’m not very expert, but I have some experience with the SmartSub which I’m happy to share. I was involved with the early development efforts with Berger, the lead engineer at Vifa. We co-developed the Class D amp at its core in the early 90s with lots of trouble and headaches. We persisted to produce our first powered subwoofer in 1997. As time went on, Jim added his patented room boundary compensation circuitry and voice coil thermistor compensation to counteract thermal compression. I was not in the equation after 1996, but I tried to register my opinion to Jim to allow user control of volume. But, as always, Jim’s MO was to make it "right" period, which in his book is flat anechoic with no user interference allowed. I’m not conversant regarding the SS technicalities, but it is theoretically possible to increase gain in the SS amp, (which I would love to do.) In the absence of schematics, I have tried, but found no one to reverse engineer the unit for either repair or such a volume adjustment mod. But, developments with the Thiel Audio IP rights may change that landscape. Stay tuned.
Regarding your LFE solution. It gets you volume adjustment, but bypasses all of the room boundary compensation circuitry. I haven’t tried it, but am told that LFE is far less musical and more room interaction interdependent. My own room suffers from needing more bass than the SS delivers, which is a common complaint. I recommend trying your hand at tricking it to thinking it is farther out in the room than it is, which will increase its output relative to its real location closer to the reinforcing boundaries. In my particular case, the SS is at a side wall about 5’ from the front wall, but I set the controls at 1’ from the side wall and 3’ from the front (some iterations are in metric equivalents.) When my installation got way better is when I set the SS2 through the wall with the baffle flush, while leaving the controls set as before. I use FuzzMeasure in my work, and FM shows this installation to be flat in this room to about 15Hz. It sounds very good. Maximum reinforcement would be from the floor/corner position, which in many rooms would stimulate maximum eigenmodes, but is not possible for my particular room (see previous descriptions) even though it is quite free from those modal problems. The point is that you can play with actual vs dialed position to get more bass from the SS.
Feel free with any questions, and let us know how your experimentation progresses.
Tom
