I've had the VTF-3 in place for a few days now. I have not yet made any adjustments using REW, though I plan to at some point. I have a difficult room that I'll describe below. I am also quite familiar with it as we've been here since 1995 with more speakers having passed through than I can recall. Unfortunately, I no longer have any test gear to prove or disprove my thoughts and impressions.
My home was built in 1910 and features 10' ceilings, fir floors, and lath & plaster walls. The partially finished basement is about 3/4 the size of the main floor. There is also an attic. They built homes differently in 1910 so there wasn't a whole wall open to using as a front wall for the system. What does serve as the front wall has an open doorway to the kitchen about 1/3 of the way in from the left side. The wide molding used at the time places the outer right edge at the mid point of the wall, which marks the center of the room. The back of the room is open to another room only slightly smaller, the back wall of that room is about 26' from the front wall where the system is. There is a window on the left of the front wall just over 3' away from the front wall with curtains and a doorway to a bedroom in the same place on the right. The doorway in the front wall forces the front speakers toward the outside of the room and close to the side walls. Typical placement is 12 - 18" from the side walls and about 3' from the front wall. Side reflections are managed by the drapes on the left and the open doorway on the right. A 50" TV is mounted on a swinging wall mount that allows the TV to be moved to one side when not in use and moved to a center position for viewing. There is a 9' x 12' oriental wool rug from the 1930s (w/pad) covering the floor. Both my original sub and the VTF-3 sit in the same plane as the front speakers and in the middle position. The listening position is 11' from the plane of the speakers.
Although my sub had 2 12" drivers, those drivers are woofers rather than subwoofers, and it was underpowered at about 240 Watts. Yes, it would reach 20Hz, but not with authority or much texture. It was fine for its time 30 years ago, but just not capable of performing alongside a well-designed modern subwoofer. Its weaknesses became more evident when I purchased a pair of Arendal 1723 S Monitors. My sub simply is unable to keep up with them. Compared to many modern subs my sub is huge. I built it from 1 1/4" MDF including the internal bracing which means it stays where I put it. Large and underperforming, it is time to retire an old friend.
The VTF-3 arrived earlier than originally predicted. That was unexpected given the 4th of July weekend. I had just moved my sub from its position perhaps a minute before FedEx arrived. It wasn't long before I had it unboxed, hooked up, and playing. I followed the initial suggestions regarding Q adjustment, EQ, x-over, and volume. Current settings are Q=.7, x-over=80Hz, 3" port plugged, 4" port open, EQ1, and volume at about 1 o'clock.
I didn't listen critically for the first couple of days, though I did turn the volume up when playing deep bass just to feel it under my seat. Hsu includes a test disc with their subs. The first track is an excerpt from Saint-Saens: Organ Symphony, Second Movement containing a prodigious 16Hz sustained tone. The VTF-3 reproduced that 16Hz louder and more cleanly than anything else that has been in my home has produced any bass tones. So, that was fun!
Later tracks include stereo pink noise, mono pink noise, and L-R pink noise. I mention these because when listening to these tracks and moving my head laterally side-to-side I heard some oddities I hadn't expected from the Arendal speakers. As I moved toward each side there was a distinct in-out-in-out effect that struck me. I have not heard this to this degree from any speaker that has been here previously. I'm not ruling out a room issue, but no speaker I've had here has produced this to such a noticeable degree. More than any other speaker, I have struggled to obtain a stable soundstage. Facing the speakers in various toe-in positions produces changes in timbre as expected, but small head movements produce the same in-out-in-out effect laterally or forward and back. I initially noticed something when particular instruments normally panned toward one side but still well within the image seemed to disconnect from the image and anchor directly at the speaker. This effect was inconsistent and changed with the track, though consistent across sources. Since I am without test gear I am unable to investigate either phenomenon.
I was easily able to obtain an acceptable blend between the VTF-3 and the 1723 S Monitors. My old sub's x-over was 12db while the Hsu is 24db. The midbass is tight and punchy, easily matching the Monitors. Bass extension is the best heard in my room so far. The most pleasing aspect of the VTF-3 for me is the articulation of its bass performance. Bass lines that previously were hinted at are produced cleanly and accurately. When the content is there in the recording the sub reproduces it. Instead of flat tones drooled out, the bass is articulate and textured if it's in the recording. This is a highly important capability to me.
Movies and TV make up about 40-60% of my listening. It varies. Sometimes a majority is music, sometimes a majority is movies. The VTF-3 is substantially more powerful and dynamic than my sub requiring me to be more careful with the volume control. I have good neighbors, but I could easily overpower their TV and rattle their windows and knickknacks with the VTF-3. Uninsulated lath & plaster walls in both homes that are less than 30' apart make that a real possibility. If I were still in my teens I don't know that I could resist the temptation.
Subterranean vibrations through a wood floor and into my chair are a new and welcome addition my sub simply couldn't produce. The VTF-3 can and does when called upon. More important to me is the articulation and texture the VTF-3 can reproduce musically. The smaller footprint is also more pleasing to my wife. I am well pleased with my purchase at this point. Will I add a second VTF-3? Not in the foreseeable future. One is more than sufficient for my application. Moreover, I seriously doubt I could get my wife to allow it.
I don't plan to start feeding my technical obsession again, but I do plan on purchasing a miniDSP UMIK-1 and using REW to get the best I can in my room, which is already pretty good. But of course, better, right?