Measuring conditions: Air temperature: 10-15 C
Atmospheric pressure: ~1020 hPa
Wind speed: 1-3 m/s
Weather: Sunny, partly cloudy
Once again it’s that time of the year. No, not super bowl or spring break but time for the Finnish subwoofer tests instead! Since the last measurement session, many interesting commercial subwoofers were announced, not to mention even more interesting DIY subwoofers. So naturally a new measurement session must be held in order to find out how these new subs fare against the older rivals and also between each other. The first weekend of May looked promising when it comes to weather, so there was it. Again we had so many pre-registered participants that we had to arrange a two-day event. It’s pretty much impossible to measure more than 12-14 units in a day unless one wants to be there all day round.
This time we took total of 23 measurement sets (some units multiple times due variable tuning), quite commendable amount, even if I say so myself. The weather was quite nice, though much chillier than last spring. We had a small shower at the very end of the second day that eventually made us to abort the session. Luckily there was only two subwoofers to be measured, so we measured them on the next weekend. Since the ambient temperature was on the chilly side, maximum output measured with the long sine sweep method on the control/reference unit (BK Monolith-DF) was little bit higher (1-2 dB depending of the frequency) than last spring. To make that difference even smaller in the future sessions, I adopted a new method for measuring maximum output – the CEA 2010 standard. You can read more about it on the Subwoofer Tests Explained thread. Also notice that the maximum output plot shows the maximum output before severe compression, meaning it may not be the absolute maximum output (especially in upper bass range). The CEA 2010 test shows better the absolute maximum SPL in upper bass range. So remember to check these results:
http://www.hometheatershack.com/foru...mpilation.html 
SVS SB12-Plus was used as a reference subwoofer to ensure that the frequency response of the system nor the absolute SPL didn’t change between test days. Here is the relative difference between the frequency responses measured each day. +/- 0.2 dB can be considered identical when noticing normal variations in background noise etc.
I also measured the difference in THD between each day. Here’s a small gif animation which shows that the difference is very small, almost nonexistent.
Again many requests and inquiries were sent to both subwoofer manufacturers and Finnish importers, but sadly not many were answered. I guess most of them are thinking that they would lose potential customers if the true performance of their subwoofers was revealed. Therefore I must congratulate and thank
Kymen Laatulaite and
Marek Sound for bringing their subwoofers in. Also thank you to
HSU Research and
L-Sound/
SVS for assistance in getting their subwoofers here. Naturally I’m also grateful to all the private persons, especially DIY guys, who were kind enough to bring their subwoofers. The measured data was sent to all the big players prior to publication so that they could check it against their own data.
Thank you to Maukka, pictures were again superb! Also thank you to Goodguy, geecb and jhautajoki for helping me out with the arrangements regarding the test. The next measurement session is already being planned. Subwoofer manufacturers and DIY’ers – start your engines!
Links to subwoofers tested on this round: B&W PV1 BK Monolith-DF BK XLS200-DF MK2 Chorus Vertigo XLS 07 DIY Adire Audio Tumult 15" MK1 sealed 100L DIY Peerless XLS 12" ported 85L DIY Peerless XXLS 10" sealed 50L DIY Rythmik Audio Direct Servo 12" sealed 56L DIY TC Sounds 2xTC-2000 15" sealed 140L DIY TC Sounds TC-2000 15" ported 270L DIY TC Sounds TC-2000 15" sealed 90L HSU MBM-12 HSU VTF-3 MK3 (maximum output) HSU VTF-3 MK3 (maximum extension) HSU VTF-3 MK3 with Turbocharger Monitor Audio BRW10 SVS 20-39PC+ 20 Hz tune (Plus 12.3) SVS 20-39PC+ 16 Hz tune (Plus 12.3) SVS 20-39PC+ 12 Hz tune (Plus 12.3) SVS PB12-NSD SVS SB12-Plus XTZ 99 W12 (maximum output) XTZ 99 W12 (maximum extension) No material may be reproduced in part or in altered form without permission. Copyright © 2007 Ilkka Rissanen and Mauri Eronen (pictures)