You're absolutely right about needing proper measurements to confirm, shadyJ. As usual, I really only go by my own experience with what I've heard and had the opportunity to compare. I definitely love to compare my experiences with the professional measurements and reviews. I haven't found myself to be too far off so far. But I have occassionally had audible experiences that don't line up perfectly with the measurements.
In any case, the unfortunate bit about the specs that are found on the various manufacturer's websites are that they don't say at what volume their quoted -3dB points are being measured. I mean, we typically assume that it's a 1Watt/1 meter type of claim, but we never really know for sure.
I've found, both with listening and with the measurements that pro reviews have done, that HSU's claims seem to be a little exaggerated. Basically, I just look at what they claim for their "max output" modes - with both ports open. Those seem to line up with what I've personally heard as well as the measurements. It seems that with one port blocked and in "max extension mode", they do provide linear response to a lower frequency, but only at reduced output levels, and the frequency response does not remain linear as the volume is increased. The 20Hz and lower output basically gets "stuck" at that lower output volume and never really gets any louder, even as the higher bass frequencies do get louder. Since I listen at reference output levels, this becomes an issue for me. For someone who only ever listens at lower output levels, I imagine it's perfectly fine and does deliver the claimed specs.
I've simply found - at least listening to it - that the FV12 plays nice and linear to just below 25Hz - but more important to me, it remains fairly linear with the same sort of relative frequency response as the volume increases. That's one of the reasons why I personally prefer it - especially at the $500 price point.
With the Legend, it didn't sound the way I would expect a sealed sub to sound. It didn't have the traditional gradual 12db/octave roll off that starts up around 40-50Hz. Instead, it played linearly down lower and then dropped off rather quickly in the low 20Hz region. It basically mimicked the sort of slope I would expect from a ported design to a large degree.
There are measurements of the Empire, and it looks to have a similar sort of design. It seems that Epik is going for a more linear shape and more output down low than a traditional sealed sub would produce without any EQ or filters. Perfectly fine design choice! It just isn't quite what you'd expect when you see "sealed" is all
I like the VTF-2 a lot, don't get me wrong about that! Personally, I like it a bit better than the Legend, but that's just individual taste. But I like the FV12 just a little bit more than the VTF-2. It's by NO means any sort of large difference between those two. They are WAY more similar than different. But given that the FV12 costs a little bit less and because I happened to like its sound just a hair more, I tend to favor the FV12 is all.
The LFM-1 Plus - being so similar to the old VTF-3 MK2, is also very similar to the VTF-2 MK4. But even though they're so similar, the Outlaw subs are a little bit different from their HSU siblings. You can see that somewhat in the LFM-1 EX measurements vs. the VTF-3 MK3 as well. Again, very similar designs, but the LFM-1 EX - whether due to its different port orientation or perhaps due to some small differences in the amp or tuning of the filters - isn't quite as linear as the VTF-3 MK3, but it's got a bit more 20Hz output. The LFM-1 Plus is similar when compared to the VTF-2 MK4. They're much more similar than different, but the LFM-1 Plus does seem to hit a little lower. And even though it's not even twice the amplifier power, it does have a touch more headroom than the VTF-2 or the FV12 for that matter.
Honestly, they're all pretty darn close. It really is SMALL differences. But a lot of people can't really order all of them and compare for themselves, so I try to mention even small differences in the hopes that it might help. To me, the Legend has enough of a different sound that I think it's worth it for people to hear it for themselves. I can't predict a person's taste, so they might prefer the Legend over the FV12 or VTF-2. Between the FV12 and VTF-2 though, that's really splitting hairs, IMO. I'm listening to individual test tones in 1 Hz increments during an audition. When I say that the FV12 plays a little lower than the VTF-2, I mean A LITTLE. Like literally 1 or 2 Hz! lol
To me, that's certainly a small enough difference that I could chalk it up to a difference in filters in the amp, or just a difference in the driver itself. A larger cabinet would typically indicate lower tuning, but if it so happens that the FV12's driver has a tiny bit more excursion, or the filter on the VTF-2 is just slightly more aggressive or something, in a case like this, that's certainly enough to explain what I heard. It could also simply be that I DO hear these subs in an actual room. Certainly the small variances in placement could be enough to explain what I heard as well! But the point is, in so far as listening to the sub, the FV12, at the very least, doesn't give up any extension to the VTF-2, despite it having a slightly smaller cabinet. There's also the fact that the FV12 only has a single port while the VTF-2 has two ports. With one of the VTF-2's ports blocked for "max extension mode", I believe it has a smaller port area than the FV12, but with both ports open, it has more port area. So that could explain why the FV12 plays, like, 1-2 Hz lower as well, since it's basically "splitting the difference" in port area of the VTF-2's two modes.
