Philosphies on subwoofers: as I see it.


From what I have read and heard, there are a couple of philosophies on the use of subwoofers.

1. The subwoofer is used to add the low frequencies that the mains leave out. For example, if the mains don't go any lower than 50hz, then the subwoofer is used to cover frequencies belowe 50hz. From modest, personal experience, I have found that this is tough to do as you can never tell where the mains actually leave out and where the sub actually kicks in. There is a chance of sever overlap or worse, some frequencies will get left out.

2. The other way I have seen subwoofers used is to augment the mains. I have seen this done where the mains will go down really low, 35hz or below, but the amplifier used does not do very well in the lower register and the sound tends to roll off and disappear. A subwoofer is used to augment the very low frequencies and boost the bass. This can also be tricky, but not as hard as the previous method, in my opinion. With this method, I have found that the subwoofer does not do as much work ,depending on the crossover used, and can sometimes go unnoticed until it comes across a low frequency and a pleasant surpise comes around.

I have also seen and heard about people using subwoofers in stereo. Low frequencies are supposed to be un-directional, but some subwoofers, like the Vandersteen, are capable of reaching and crossing over at very high frequencies, producing clean sound, and thus, I think, directional waves.

I have a question for Vandersteen subwoofer users; is it possible to have one Vandersteen subwoofer in a system that crosses over so high that it could change the focus of a system. I would see this as a good reason to have two Vandersteen subwoofers instead of one.

Comments?
matchstikman
Sdcampbell and Bigtee are both guys who are strong advocates of stereo 2wq's and use them to great advantage. Vandersteen himself, as Scott mentioned advocates this as well. Eventually I want to add a second sub myself.

Your question about crossing over too high indicates that you need to study a bit more about how the thing works. I use one sub and it sounds great providing you choose the correct filter value and placement. Two 2Wq's may be significantly better as Scott indicates, but one is SIGNIFICANTLY better than none in many room situations. Your #2 confuses me as to what you are trying to say? The response is quite predictable using Vandersteens method and providing again as Scott mentioned the main speakers have predictable response low enough. No you can't mate a Vandersteen sub well with say, Spica TC 50's(tied that, nuf said) or other small speakers that will give you a suck out or gap before the woofer takes over. I can't say that I have tried all the current woofers out their, I can say that the Vandersteen is an excellent choice based on my experience and mates well with even Maggies or Martin Logan CLS and with a great number of dynamic speakers as long as they can go low enough below 80Hz to allow the 6db per octave x-over to do it's thing.

Bottom line is if you have the cash and the space buy two, if you don't(like me),buy one and decide for yourself.By the way, my system has no focus problem using one, although I would love to try two of them here. You can always add a second 2Wq anytime you can afford it.
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Good luck and enjoy !
The Vandersteen 2Wq sub has a crossover system that is designed to make the transition from main speakers to sub at 80 Hz. The crossover that is inserted between the preamp and power amp rolls off the frequencies below 80 Hz that are going to the power amp, while the subwoofer's interal amp has a boost curve that is the inverse of the crossover rolloff. The result is flat frequency response. Because Vandersteen designs the 2Wq this way (but NOT the V2W, which gets it signal from the LFE output on a surround processor), it is necessary to have main speakers that are fairly flat into the upper part of the first octave (20-40 Hz). If the main speakers are not fairly flat down to the upper 30-Hz range, then there will be a dip in frequency response in the range where the 2Wq and main speakers overlap.

Richard Vandersteen is quite direct about the desirability of having a stereo pair of 2Wq subs (less necessary with a V2W, which was designed mainly for home theater LFE). Not only does having a stereo pair of 2Wq's enhance the listening qualities of the system, but it also provides an additional 3-6 db of gain when compared to a single sub (thereby giving the pair of 2Wq's roughly the same output as a single V2W). I know from my own experience with the 2Wq that having a stereo pair makes a SIGNIFICANT improvement over a solo sub.