SVS SB-2000 or PB-2000

After owning the PB-2000 now for over a month I can confidently say that I never had owned a proper subwoofer in the past. Getting the SVS dialed-in and through the break-in period took some time but I am now continually blown away by the tightness and overall focused rumble of this subwoofer. Incredible! There have even been times while watching a 5.1/7.1 blu-ray when there is literally no low frequency "sound" (that I can hear with the limitations of my human ears) but the subwoofer produces an amazingly "invisible" vibration that I can feel in my gut. Spectacular! I am now an SVS convert and wished I would have gotten one sooner. Who knew?!

 

After dialing everything in that I can I am still curious about the phase dial that ranges from 0° to 180°. All of my "subwoofers" in the past only had a switch of either 0° to 180°. This dial confuses me a bit because I'm not sure where to set it. In the case of dialing in this SVS PB-2000 I ended up choosing all the way to 180° because that seemed to produce the biggest "oomph!" but I have to admit I'm not really sure where I'm supposed to set this or how I setup some sort of frequency analyzer to literally tell me where to set it.

Regardless, I'm still more than pleased with the performance of the SVS in comparison to my past JBL wannabes. Just curious if there's something I'm missing on the frequency spectrum with this phase dial.

 

You would need a real time analyzer to properly set up your phase dial. At your seating position, you will see some dips in the frequency response and you adjust the dial slowly to see if they disappear.

But if your receiver has an auto calibration option and your sub has a distance value, then that does exactly the same thing. Once your system is calibrated, don't touch the sub's phase knob.

 

Short of being a professional sound engineer with access to a real-time analyzer what do the makers of high-end subwoofers with variable phase dials expect normal consumers to do?

And I suppose this is the answer. However, I've never had any luck with getting the YPAO on my Yamaha receivers to work properly. I've traditionally set all of the volumes for all eight speakers with a sound meter but never had to worry about more than two settings (a 0° or 180° switch) for the phase on a subwoofer until this SVS. As I mentioned above, I have it set right now at 180° because that sounded better than at 0° and really don't have any complaints. Still, I am infinitely curious whether it should be set at anywhere between 1° and 179°! Perhaps I should start saving for a real-time analyzer that I will only use once?!

 

The phase isn't part of the level matching, it's part of the distance setting. Or better yet, delay. If your right speaker is closer to the mic than the left speaker, the auto calibration will add the proper delay. On an old Kenwood, I had to convert feet to milliseconds. Of the 5 speakers in the system, the farthest one away had zero delay. Everything else had some type of delay value because they were closer.

If your sub is 180 degrees out of phase with your mains, then the small overlap in frequencies will be cancelled out. So the best bet is to just turn the phase knob and stop where it is loudest. Let's say your crossover is set at 80hz. You would play an 80hz tone and watch a free SPL meter app on your phone. As you adjust the phase, your meter will show it getting louder or quieter.

Why 80hz? That's the most common crossover frequency. But doesn't my crossover in the receiver keep my mains from playing anything below 80hz? It's not a brick wall. If your crossover is 12db per octave then at 40hz, your tone will be down 12db. Same way with your sub. At 160hz, you will still hear material but it will be 12db lower.....I'm a fan of steeper crossover points. My receiver has a 12db crossover and so do my amps that power my mains. I've also set those at 80hz so I have the equivalent of a 24db/octave crossover.

For some people it's not worth the time and effort to buy an RTA and a dedicated subwoofer EQ. It was for me. The difference was night and day. But you can at least set your phase with a free app. Although I use a smart phone mic from Parts Express for my quick and dirty SPL measurements. I think it was about $15.