My friend owns an SVS PB10 subwoofer and he was kind enough to let me borrow it over this weekend. My system consists: NAD T743 reciever Sony DVD-player Wharfedale Emerald 97 mains (2x6.5" bass each) Wharfedale surrounds (no center) Phoenix Gold 215i 2/3oct. EQ/active crossover RS dB-meter (custom calibration file) 2GHz computer with lots of nice programs to play with My room is quite small, only about 1500 cubic foot. It has one 0.8m x 2m opening to a bigger room. No door between. It's on second floor, concrete floor and ceiling, one wall is also concrete, other walls are softer materials. Sub was placed between main speakers, about 1m from back wall and about 1.8m from listening point. All speakers were calibrated at 85dB with AVIA, sub was calibrated at 79dB (4dB cold) with music and at 84-85dB (1-2dB hot) with movies. Reference level was calibrated at 0.0dB master volume. Phoenix Gold EQ was connected between NAD's pre out's and main in's. It has 24dB/octave active 2-way crossover, xo frequency selectable between 30-600Hz. I used ~50-60Hz crossover setting. Small adjustments were made with EQ, -3dB at 63Hz and -2dB at 100Hz. Here is the first FR: (music and movies) (not absolute SPL's) It is quite smooth with good extension to 15Hz. I listened some music, but I was having this strange feeling that there was too much bass at the lower end. Some songs that go deep enough were some way boomy and not as musical as I have heard them before with my mains and other subs (my mains go all the way to 20Hz, F6). I tried to EQ that bump away, but my EQ wasn't good enough. BFD would have done the trick, but I didn't had it. Then I had a crazy idea. If you have some excessive boom in your speakers, what can you do? You shut the vent and make it a closed version. Why wouldn't this work with subs also. PB10 has a rather large box so Qtc would be quite low (<0.6). I stuffed some high density foam into the vent and I had one closed PB10 in my hands. Quess what happened to that bump? Yep, it was gone. So was the boomy and excessive low end when I fired up my first song. It would have been interesting to explore if that enhancement would have been made with EQ'ing only. Maybe I need to buy that BFD and find out. Maybe a high pass filter (not very steep) at 25-30Hz would have done the same trick. I listened the same tracks again and I must say I prefer the sealed version. If the song's bass was only at 40-50Hz range and upper, there wasn't a big difference. But if song had some very deep sub 30Hz bass, the difference was very noticeable. Sealed version had the same extension but it was more "musical". Tight and not boomy at all. With movies this is a one crazy subwoofer! I demoed most movies at -5-10dB from reference ("hot" tracks) and I was seeing 100-105dB peaks on my RS-meter. I have heard a bigger SVS (PC+ 20-39) in a bigger room, but in this smaller room it gave nothing away to it's bigger brother. I have also heard Velodyne DD-18 and I must say that at these "resonable" levels it is a tight match. Of course bigger Velo pulls some distance if pushed further. Yet 105dB was not the limit in this room. This a graph from Finding Nemo, chapter 10, sub sliding. -10dB reference, DTS track which is very hot. Total power means the level you'd see in your SPL-meter (compensated). I was standing 2 meters away and my pants were waffling bigtime! Again, this was not it's limit and there was still some juice in the trunk left. How much? I must do it again tomorrow at -5dB. Finding Nemo Graph1 I also did some max SPL tests to find out where the compression limit was (xo was at 60Hz). I used TrueRTA's QS option with 8kHz sampling freq. Each time level was boosted 5dB until compression occured. At 20Hz it happened at 106dB! Quite impressive for a $429 subwoofer. All SPL's are absolute numbers, they were carefully calibrated. I also did some THD tests to find out it's capabilities to produce CLEAN bass. And I was about to find out that there were almost no limits... Selected graphs shown below. None of these are limited SPL. (that 50Hz fundamental shown in every graph is just minor ground loop/50Hz electrical hum) 30Hz - 101dB 22Hz - 101dB 22Hz - 104dB 20Hz - 98dB 20Hz - 100dB 15Hz - 91dB 14Hz - 73dB Finally at 14Hz it gave out! I was literally blown away with it's capability to produce clean bass. 100dB at 20Hz and my whole apartment was shaking! Here is a small review from Velodyne DD-15 (only measurements), of course it is measured in anechoic chamber, but if you look at the THD level at 20Hz and 100dB level, it is the same as with PB10. How much the room gain helps SVS, we can only guess. But that is atleast something to think about. I did also measure THD levels with closed SVS. I found out some interesting numbers. 16Hz - Vented 16Hz - Closed 20Hz - Vented 20Hz - Closed At 16Hz the closed version was even better! And even at 20Hz, it doesn't have much more THD than the vented version. 25Hz and higher they were almost the same. And remember that I did prefer the closed one with music. Actually I didn't test it with movies at all, maybe tomorrow. I must say that SVS PB10 is an awesome sub. Even if it would cost double it would be quite a bargain. My hat is of to SVS! Feel free to comment and post your thoughts!