Two subwoofers??

I have an MX-700 sub. I love the speed that the twin 8" drivers deliver, but I could use more "impact". I know that this sub is room sensitive, and it has been placed with care, so I am fairly certain that I am getting all I can from the sub. I have been toying with the idea of adding a second MX-700 (my wife does not know this). I know that you can gain up to 6db from a second sub, but I am worried about sound cancellation. My question is this:

Has anyone tried a second sub, and what were the overall effects?


For anyone that has a second sub, what placement is the best to avoid sound cancellation?

Love to hear from anyone whose wife is more understanding of this fun hobby.......
I've got a pair of Sunfire True Sub Signatures in my main system. I'm using them stacked, along a wall. I have adjusted the phase of one of them by ear to avoid cancellation with my main speakers. I've set the phase of the other one to be identical with the first one, so they will reinforce rather than cancel. It sounds pretty good.
I've been using a pair of Vandersteen 2Wq subs for about 4 months, and wouldn't go back to just a single. It isn't just a matter of additional sound levels -- the quality of the deep bass is better. Also, in many rooms having a pair of subs also reduces problems of room loading, standing waves, and phase cancellation.

The Vandy 2Wq sub was actually intended to be used as a pair, but based on my experience, and others that I know who have 2 subs in their system, the quality of the sound is much improved with the second sub. If you can borrow a second sub to audition, I'll predict that you will like the results.
I'm using a Legacy Pacemaker (2- 15" drivers with seperate enclosed 175 watt amps). One driver is left cannel, the other is right. There is no summing network to screw up the sound. -3dB point is 16 HZ. Works very well for me. Don
I have been running dual B&W ASW800 subs placed about 4 feet rearward of my 801 III's. I love the seamless blend and would not go without them in my larger room. I run them from the RCA out of the pre amp since everything else is balanced.
I've experimented with my pair of Titan IIs quite a bit. I've stuck them in the same corner (got the absolute highest output level this way). I ended up with one almost in the corner behind the main speaker and one about 2/3 of the way along the wall behind the main speakers. It get very smooth room response and very good overall performance. My advice would be to experiment. Every room and system is different.
You should take a look at the Bag End Infra-sub 18 inch subwoofer. Extremely musical and tight. Used usually sell for around $850 and new at $1600.

There is no other sub that I am aware of at this price break that can even begin to approach the musical definition that this 18 inch sub reproduces which is all the way down to 8Hz.

There is no such thing as an 8 inch subwoofer especially at this price range. No matter what they say. An 8 inch sub which bottoms out at 30Hz is not a sub. It is a woofer.
Stehno, out of curiosity, do you know where the 18" driver in the Bag End "bottoms out" at ? For the record, it's something like 70+ Hz. They electronically manipulate the signal from there. While their specific approach is slightly different, this can be done with nearly any design. How effective it is depends on how well the designer does their homework. Sean
Sean, perhaps I'm not understanding your question and subsequent statement. Could you please elaborate?

As for personal experience, A few years ago, I demo'ed the Bag End Infra-sub in my home for several weeks. At that time, anyway, I was quite impressed with it's musicality and taught definition. I really could not hear a thing until it reproduced the appropriate notes. It was extremely tight. There have been a few reviews on the Infra-sub and they say much the same. Supposedly, it is used quite a bit in professional recording studios.

The main reasons I chose not to go with the Bag End was because it lacked a few features and configurabilities I was looking for at that time and because I was not overly impressed with it's construction quality.

But it worked quite well. And if memory serves, I would put it at or near the top of the list of subs to audition in the $2k or less price range.

I was referring to your comment about an 8" that bottoms out at 30 Hz being a woofer rather than a subwoofer. As i mentioned, the 18" driver in the Bag End actually resonates at 70+ Hz. As you might guess, this makes it worse in "stand alone" performance than many "good" 8" woofers.

The designer chose to use a driver that resonated outside of the audio band that it would actually be used in. This is common practice for most drivers, but is quite rare for a sub. By crossing over below the point of resonance and EQ'ing the response accordingly, he is able to achieve more linear output ( due to the pre-determined sloping output level ) without any in-band resonances or amplifier loading / driver control problems. The major drawback to this is that it takes a LOT more power to do this effectively. Given the ease that one can pick up a high wattage amp nowadays, that factor is almost a moot point though. Sean
Sean, design concepts aside, what did you think after listening to the Bag End Infra-sub?

As for my comment about an 8 inch woofer bottoming out around 30Hz? I stand by it. In my experience and reading, it appears that there are very few if any 8 inch drivers or even 10 inch drivers that can adequately reproduce frequencies below 30Hz around the price break of perhaps $1500 or less. Jeepers, it appears that there are too many 18 inch subs that can't go much below 30Hz.

As I've stated elsewhere, the size of driver seems to become less important in subwoofers at more expensive price breaks.

I'm certainly not going to pretend to understand how a subwoofer 'should' or 'shouldn't' be designed because I don't know and don't care. But as with manufacturing most anything, manufacturing a subwoofer to do what it really ought to do is probably more of an art than a science. And the execution and the whole is hopefully greater than the sum of it's parts.

By all means, correct me if I am wrong.

With that said, I will say again, that yes, the Bag End has a few flaws, (which component doesn't?) but in my room two years ago with my configuration, it certainly sounded impressive, just as some reviewers had said it would.

But again, Sean, I'd be really interested to know how you think how the Bag End sounds.
Bottom line ? I like the Bag End. Like anything else though, you have to play with the installation to get best performance from it. Sean
The advantage of using two subs is that you can place them next to each speaker which should allow you to cross them over at a higher frequency then if you use just one. Not using the A+B summing will let them run 3dB lower than one sub alone. Looks like a nice option albeit at twice the cost. Question Sean, you state that the Bag End resonates at 70Hz. Is a user OK as long as he crosses over below this frequency?
I'm assuming that you are looking at 2 subs for a home theater setup. For a home theater setup, you would want to get a larger sub like a 15" or an 18" for more slam/boom in crashes and explosions. These larger cones tend to be more sloppy and slow. (the larger the surface area, the slower it is going to move and stop). If you are looking for a sub for a musical setup, the smaller the driver the better. (most decent speakers do not need a sub for music in the first place. If you have the right room, the right setup, and a decent 2/3/4 way speaker, you will get a more true-to-life sound than emphasizing the bottom end. For example, read reviews of the famous Revel M20 small monitors, the reviewers indicate that they are not missing anything and prefer the sound of the M20's without a sub). If you think you still need a sub, try to audition one that has multiple small drivers which will be faster and more accurate than that of a larger more sloopy driver setup.
Search4tas must be smokin something to think he's not given up a thing with his small 2-way M20 monitors. If that was the case, Revel probably never would have made the Studios or Salons which in my opinion are way better than the M20's. And the stuidos and salons prices which is 5 to 8 X's the cost of the M20's would certainly make us believe that at least Revel thinks the other speakers to be superior to the M20's. Especially in the lower regions.

Search4tas also misinterprets the reviews of the M20's. The reveiw in Stereophile says no such thing. Only that the M20's sound bigger than they are.

S4T's comments about the subs being sloppy, slow, crash, boom, bang are almost as obsurd as his other comments. There are good and bad subwoofers big and small. I've heard as many smaller subwoofers with no musicality as I have heard larger subs.
I have certainly gleaned alot of good information from the follow-up threads to my original question. After reading all of them, I have come up with the following:

1. Everyone seems to agree (except for Search4tas) that I could certainly benefit from two subs. Let me clarify, that I have auditioned the M20's, and they did have a great bottom end for a mini-monitor.

2.The end result from the use of two subs is heavily dependant on room placement and room dimensions / layout.

Let me put another question out there then. My previous question and all of the resulting threads assumed that I would use two subs with 8" drivers (as I stated that speed was a priority). My question then is this: What about two subs; one with 8" drivers that would be x-over to kick in between 80Hz and 40Hz and a 15" sub with a x-over to take over lower than 40Hz. This would require an external x-over in my setup, but would negate most of the sub placement problems. Anyone tried this????

Thanks for all of the great info so far......
I don't see the need to use three subs as you suggest because the Velodyne frequency response is flat from 100 Hz down. Using two subs for the front channels and a third sub for the home theater channel would be sweet if you have the budget plus floor space.
I was not suggesting using three subs. Let me clarify. I have B&W CM2 speakers for the front and surrounds. These are great speakers if only a little light on the bottom end. To fill out the lower end, I now have only the one sub, and am exploring the idea of a second sub. My previous thread was to inquire if anyone had tried a two sub arrangement that used a large driver sub for lower freqs (40Hz and below) and a smaller driver sub for the 80Hz to 40Hz range.
Sorry about the misunderstanding. With the extended frequency range of your better quality subs it is not necessary to split the 80Hz to 20HZ range. So I still think that using an independent sub per channel would be your best option.