Well.. The verdict is in.. The Hsu VTF-15 will be sold
I got everything hooked up this afternoon. The iNuke software is pretty straightforward and bridging the amp was cake. I am also a fan of Speakon connectors now, I really like them. After getting everything hooked up, I did some A/B comparisons with the VTF-15H, and I measured an easy 6-7db more gain at the LP with the four Ack subs. The Ack subs really have lots more steam under 20hz. I ran the VTF in full output (both ports open) and full extension (one port closed) and there was just no contest. The Ack subs were moving my pant legs at the LP and they sound extremely tight, and with four of the Ack subs in the room, the bass response is just very smooth. It is really hard to describe, but I absolutely see the value in having multiple good performing subwoofers spread out in the room. I did limited testing pre and post Audyssey MultiEQ, and liked what I heard with MultiEQ, but REW will confirm.
I watched the Dark Knight Rises (I have been waiting to watch this since I decided on this project) and I still have a huge smile on my face. I am just so happy with how everything sounds and I have to say that the project met my expectations. I have more output and more extension and I did it for $1K, which is about what I paid for the VTF-15H shipped to my door. Four DIY Ack subs for $1K (that cost includes everything) easily gives me the performance of 2 VTF-15H subs, and it would really take 3 Hsu VTF-15H subs to equal or best the 4 Ack subs, and that would be over $3K shipped.
I still need to dial everything in and once I get my Minidsp mic and fire up REW (I used an SPL meter, and some test tone CD's today, along with some bass heavy scenes) I suspect I will really fine tune everything and find some sweet spots in terms of placement.
Oh, and I won't lie. I am already thinking I can sell the 15H and build a couple more of these same subs
And I will definitely be doing the fan mod on the iNuke3K DSP. Even though I sit pretty far from the amp and don't really notice it during movies/TV, it is still louder than I was expecting. But the workaround seems easy, so I will be pursue the fan mod.
Attached are some shots from today. I will get some better pics soon and hope to get a better camera. You will see some shots of the Ack subs pre driver, an Ack sub next to a PA-150 (15" ported sub), and an Ack sub next to the Hsu VTF-15H. I won't lie, I really like the Hsu sub. It really is a beast, but I am sold on DIY and what you can do with the money.
Thanks again to all that helped and a special shout out to nograveconcern who really assisted with all my noob questions.
More to come!
Holy polyfill batman!
Ack vs PA-150
Ack vs VTF-15H