| AudioREVIEW's Forum Archives - All About Speakers |
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|   Just bought a new front-firing sub, couple of questions.... | Worf101
Dec 10, 2002 8:05 AM | | My current sub is a downfiring JBL PB-12. I musta got a good one cause it's given me no trouble in over 2 years (knockwood). However I saw a deal on used Hsu VT3 on ebay that I couldn't pass up so I bought it. It'll get here tomorrow. I've never owned a front firing sub. What are the placement issues. Any tips for a front versus down fire? Do I need to place it in front of the room and point it at me? My current subs an end table near my leather chair. No problems there so far but would that work with a front fire.
I'm kinda lost here.
Da Worfster |
| re: Just bought a new front-firing sub, couple of questions.... | Wireworm5
Dec 10, 2002 10:23 AM | | My sub is adjacent to my listening position facing the front wall in a long narrow room. Seems to work good, but my preference would be to have it facing me in the middle between the front speakers if I had the space.:) |
| Bass below 80Hz. is mainly omnidirectional | Richard Greene
Dec 10, 2002 4:31 PM | | If a subwoofer driver is aimed at a room surface such as a plasterboard wall or a wood floor, it will tend to rattle that surface. Concrete slab floors, however, won't rattle.
In general, bass sounds best if the bass driver it is aimed at your ears. But once again, bouncing the bass off a solid concrete surface or a very sturdy hardwood floor will make little difference.
In general, the loudest bass is obtained from placing one or more subwoofers in the one room corner nearest your ears.
In general, the best integration of the subwoofer with the main speakers would be when the subwoofer(s) is located within a few feet of the main speakers.
Placing a subwoofer in a single room corner near either the left or right front speakers provides high output and fair integration
with the front speakers.
Using two subs, with one located in each front corner near the front speakers, provides good integration but at the penalty of perhaps 3dB less output than using two subwoofers stacked in a single room corner (due to destructive interference between the subwoofers (they will be out of phase at a frequency related to the width of the room -- 565 / width of room in feet = frequency in Hz. where subs have destructive cancellations).
Placing one subwoofer half way between two front speakers or using two subwoofers as front speaker stands provides the best integration with the front speakers ... but usually a much more uneven bass frequency response (asssuming the front speakers are placed well away from the front and side walls).
These rules of thumbs apply to most rectangulars rooms.
Irregularly-shaped rooms require measurements rather than rules of thumb. |
| Bass doesnt become omnidirectional until 40hz... | cone
Dec 13, 2002 10:39 AM | | which is why most sub/satellite systems are hard to intergrate...very few monitors can do 40hz...floorstanders have the edge in this category...albeit...at a loss of precise imaging... |
| You are technically correct but your post is misleading | Richard Greene
Dec 15, 2002 5:58 AM | | When playing sine wave test tones, many people can identify the location of a single subwoofer under blind conditions when playing test tones of 40Hz. or higher.
When listening to real music where there is bass above 80Hz. coming from the left and right speakers, and the crossover uses a 24dB/octave slope, few people can identify the location of a single subwoofer under blind conditions.
Even a 100Hz. 24dB/octave slope is invisible for some people.
Subwoofers are hard to integrate mainly because of too much output above 80Hz. often from the use of 12dB/octave slope filters ... and many are placed too far from the main speakers.
I personally prefer 60 to 70Hz. 24dB/octave crossovers for my subwoofers and use additional low pass filtering above 100Hz. using a parametric equalizer. Even then, if there is significant output at 25Hz. or lower, I can often "feel" my single subwoofer is located on the left side of the room through the sound pressure that's stronger on the left side of my body.
Subwoofers are rarely 100% invisible but the bass frequency response below 80Hz. will usually be significantly better, and the bass harmonic distortion significantly lower, when using a parametrically equalized subwoofer in a room corner near the main speakers, rather than using a pair of full-range main speakers with no subwoofer.
If money is no object, full-range floorstanding main speakers using dedicated mid-range drivers, plus an equalized corner subwoofer for frequencies below 50-60Hz. makes a potent combination, especially if you like loud music (where small two-way speakers produce too much distortion). |
| 40hz is 40hz regardless of x-over....that is the optimum... | cone
Dec 16, 2002 1:51 AM | | and if your speakers are substantially below full range...say closer to 30 cycles...or lower...I wouldnt even bother with a sub...there is simply not alot of information down there to warrant the cost of a decent sub...Vandersteen model 2s are a prime example...they do need a good sized room...but so would a sub.. |
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