How to judge the quality of a sub-woofer?
So basically I want a sub-woofer for Christmas (to go in my bedroom), along with some speakers. I’ve been on quite a few sites to choose the best one (amazon, best buy, eBay, target) , but i’m not really sure how to judge them. Do the 200 watt ones just need more power than the 100 watt ones? Does that make them better?
Are you talking about powered subwoofers? If so then the 100 watts or 200 watts will be the rated power of the built in amplifier in the subwoofer. More power does not automatically mean better performance. There are a number of factors that determine how much power is required.
Rating them isn’t easy without simply trying them. Manufacturers do not provide the necessary information in the spec sheets to make any real assessment of the performance. Frequently the information they do provide isn’t accurate. They have a tendency to exaggerate power capability and frequency response. Ideally you want the sub to play as low frequency as possible but you can not depend on the specifications especially with subs of the caliber that places like Best Buy etc sells. They may claim the subwoofers frequency response extends to 20 Hz but not mention that it is -10 dB or worse at that frequency. The specification should give you the "cutoff" frequency where the output is - 3 dB. If you can find this specification among various subs then you can compare that one aspect based on that spec but it still may not be valid.
There are numerous other aspects of the subwoofer you will never find data on unless you measure it yourself or find independent measurement data posted on line some place. This site http://www.hometheatershack.com/forums/subwoofer-tests-archived/6015-index-subwoofer-tests-manufacturer-model.html provides comprehensive measurement data on a number of subwoofers. I don’t think you will find data on any Best Buy subwoofers here however.
mk
Are you talking about powered subwoofers? If so then the 100 watts or 200 watts will be the rated power of the built in amplifier in the subwoofer. More power does not automatically mean better performance. There are a number of factors that determine how much power is required.
Rating them isn’t easy without simply trying them. Manufacturers do not provide the necessary information in the spec sheets to make any real assessment of the performance. Frequently the information they do provide isn’t accurate. They have a tendency to exaggerate power capability and frequency response. Ideally you want the sub to play as low frequency as possible but you can not depend on the specifications especially with subs of the caliber that places like Best Buy etc sells. They may claim the subwoofers frequency response extends to 20 Hz but not mention that it is -10 dB or worse at that frequency. The specification should give you the "cutoff" frequency where the output is - 3 dB. If you can find this specification among various subs then you can compare that one aspect based on that spec but it still may not be valid.
There are numerous other aspects of the subwoofer you will never find data on unless you measure it yourself or find independent measurement data posted on line some place. This site http://www.hometheatershack.com/forums/subwoofer-tests-archived/6015-index-subwoofer-tests-manufacturer-model.html provides comprehensive measurement data on a number of subwoofers. I don’t think you will find data on any Best Buy subwoofers here however.
mk
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Mk answer is pretty spot on. It is important to choose the right subwoofer so it will blend properly with your main speakers. Subwoofer placement and size of the room also play a factor.
Personally I am not a fan of single subwoofer systems, as bass is stereo, and the belief that bass is not directional is completely false. With the use of single subwoofer you are now taking stereo bass information and making it mono, so now the bass guitar or stand up bass player that was recorded in what ever channel is now in the middle of the soundstage, this will effect all recordings.
Ideally if using sub-woofers is to use two one for the left and one for the right channel. Coming off the main left and right outputs and not the mono subwoofer output. They should be placed just to the outside of the main speakers. If you insist in using a single subwoofer it should be placed directly in the middle.
There is a large variance in the quality of sub-woofers. If music is important then it should be chosen on the merits of being able to blend well with your main speakers, and give you good detail of bass information. Settings and placement are critical to get right and must be done correctly. Corner loading is absolutely the wrong locations for quality of bass, and must be positioned on the same wall as the main speakers. cross-over settings should be set so it blends seamlessly with the main speakers, usually set with test tones and a vu meter but you can get pretty close with your own ears.
Use good bass material and listen to the detail in the bass notes, you should be able to hear each note distinctly. It should not sound like hes playing one note. The amount of power needed is dependent on several factors, but I would not let that determine the purchase of the subwoofer, but more its sound quality. Certainly it is difficult to audition subwoofers, but I certainly would not buy one with out allowing you to listen to it.
Your local independent hi-end audio video stores carry the better brands of equipment, know how to audition equipment and will often allow you to try it at home before final purchase.
Kevin
40 years hi-end audio video specialist
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