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Should I Add a Second Subwoofer to My Surround System?
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December 17, 2009 | by .(JavaScript must be enabled to view this email address)
This reader is adding Blu-ray and upgrading his audio to 7.1, and wants to know if a second subwoofer (to go 7.2) makes a big difference.
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Posted by Crow  on  12/18  at  12:25 PM

instead of adding a second Sub get a Butt-Kicker system!!!  it will rock…it is a powered transducer that is attached to your couch or chair. runs off of the bass output and vibrates/shakes according to the amount of bass in the audio.  Everyone that comes over to my house loves it…a start up kit with amp, transducer and hookups runs about $400

Posted by Chili  on  12/18  at  01:55 PM

If you’re getting two subs because you want to feel the bass, then get the Butt Kicker like Crow said.  That is a cheaper option to feel the bass.

Posted by BASS IN YOUR FACE MASTER  on  12/18  at  02:07 PM

BUTT KICKER GARBAGE !  GET A BETTER SINGLE SUB.  LIKE SUV PB12 ! IT WILL BE YOUR LAST PURCHASE,  MICHAEL

Posted by Crow  on  12/18  at  02:41 PM

he already has one good sub in a small room…Butt Kicker is the way to go as an add on!!!  you won’t be disappointed

Posted by CJ  on  12/25  at  08:58 AM

Keith, One other thing to consider.  When you a get a new receiver, not only do you get the higher definition Dolby/DTS audio via HDMI, but some of the new receivers also have the new Dolby IIZ format which uses (2) additional front speakers placed higher and wider than the main left/right speakers.  Do a search on the IIZ and read the reviews on it… it’s interesting.  You’ll notice that many of the editor’s including the manufacturers of both Dolby and DTS don’t give much weight to going from a 5.1 to 7.1 surrounds.  In my opinion as an installer I only use the 7.1 when I need to and that’s typically for very large rooms.  But in the quest for having the best possible experience, the IIZ might interest you.
Also if you are considering upgrading your ‘entertainment’ system, you could consider some other things like… 1. A new receiver would most likely have a 2nd zone.  What about sending audio to another area or room?  2. Most companies that make receivers have an iPod dock so you could see the metadata on your TV screen &  that you could control through the remote.  What about this as an option?  3. Maybe an AppleTV?  4.  Do you have a digital music library on your PC that you stream to your receiver?  What about a high quality external DAC for the best sound like a HRT’s MusicStreamer?  Just want you to think ‘big picture’.  Best & Happy Holidays!

Posted by Jeff  on  01/08  at  04:07 PM

I agree… having a transducer (I have 2 ibeams) allows you to turn on or off the vibrations in your furniture piece ...working together with a sub the over all experience is nice. I like it. I don’t always crank it but sometimes I do. concerts are great…. it also allows you to not have to over power the room with the sub…

for those that think they are garbage have not tried one tuned properly or installed correct. - in a big system its a small investment that is controllable and not on all the time.

Posted by Michael Moore  on  01/12  at  10:59 AM

Get another sub.  Put against the wall that is 90 degrees from the your current sub you have now.  You have just eliminated most of the wave nodes in the room.  Also try to keep them out of corners(with two subs you will not need the “corner loading”).

Posted by gibroni  on  01/12  at  10:52 PM

Here’s a different approach., a midbass woofer.  You didn’t mention the current sub that you’re using (or I just missed it).  Depending on the low frquency extention of your current subwoofer and the crossover point of your main speakers you may be able to fill a hole in the secnd octave.  HSU research offers a midbass woofer to handle 40 Hz to 80Hz allowing the subwoofer to handle 20 Hz to 40 Hz.  The reviews I’ve read claim that it makes an astonishing difference in the impact of a surround sound system.

Posted by Dave Ladely  on  02/08  at  12:47 PM

I’m afraid he’s wrong about 7.2 not necessarily being better, and the additional subwoofer would not be overwhelming as long as the sound is balanced properly.  For example, if the level was reduced to near zero, would two subwoofers overwhelm?  That demonstrates the error of that claim. The comment about the second subwoofer helping reduce nodes is correct; low frequencies have nodes, which are a real problem that is not fully addressed by placement.  The fact is that the MORE subwoofers, the less the effect of nodes. Of course, the sound needs to be balanced with the rest of the speakers as I noted.  A simplistic analogy would be one sub acting like one pebble tossed in a pond - the waves act like nodes.  Then drop two pebbles: the waves will be a bit more diffuse, a good thing.  Toss 10 pebbles; the waves will be much more diffuse.  Of course, the hit of even a second subwoofer is actually on the pocketbook, otherwise, its all pluses for sound..

Posted by robert archer  on  02/08  at  01:07 PM

To clarify the last post is wrong. Low frequencies don’t have modes, small rooms have nodes and these modes are the result of soundwaves that interact with one another.

Room placement is also very important and there are two ways to compensate for low frequency problems when employing room placement techniques; move the seating area to a position where the seating is in between the peak and null points of the modes (you can determine this in an scientific, but effective method of walking around the room to find spots where the bass is louder) or you can move the sub to different positions within the room until a satisfactory position is found.

If more bass is required the sub can be placed in the corner where it can get boundary reinforcement from the two sidewalls, the ceiling and floor. This type of placement can add as much as 18dB increase in output.

Second subs are added to a room to smooth out standing waves (soundwaves that meet at their 1/4 point). Usually two subs are employed opposite one another or in positions parallel to one another.

The perfect scenario for a room using multiple subs is the use of four (to create identical mirror points).

In a small room there are many cases where one sub is enough to effectively handle the low frequency requirements in a home environment, especially when EQ solutions like the Audyssey technology is used in conjunction with a basic home theater system.

Posted by FarmerBob  on  02/23  at  08:21 PM

The 7.2 spec is for a 2 channel (stereo) subwoofer not double the amount of sub. I have seen that you don’t necessarily “overwhelm” yourself with bass, but it becomes muddy, boxy and/or unpleasant if not throttled or tuned/phased properly. Also the problem that I have every so often is that when the ability to severely augment the standing wave at the subsonic level is present, it can have a canceling effect, where you get less or nothing. So too much bass can go past being unpleasant and just plain cancel itself out. You will need to find that “happy medium” of the room and work with it to get optimum bass which may not be as much as you would like due to the fact that the room many not be able to accommodate your wishes. More speakers is not always the solution. But this day and age technology and the newer ways of baffling sub cabinets can produces killer bass with very little. It just takes the right kind or setting thereof. Not more speakers. But . . . . personally I love bass that can stop your heart and love my Klipsch MCM W Bin with two 18” Horn Loaded Cetec-Gauss drivers. Now that’ll stop your heart . . . break windows . . . crack concrete . . .

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