MartinLogan Subwoofers- Don't Overlook Them!

@avanti1960 how do you have yours connected? They seem to have really good connection options.

Mijostyn,

Unfortunately you need to adjust each subwoofer independently.

@millercarbon   of course two subwoofers in a room do offer advantages but the design and spec of the subwoofer is critical.   At this point having two subwoofers has negated the issues I had using a single sub and until I find something to complain about two is all there will be!  
@mijostyn   you have to adjust the subwoofers one at a time as far as i can tell.  
@noble100  I agree about the directional cues when at the listener spot but while moving about the room, the sound of a single sub can change dramatically.  I had a single sub previously and the sound was so defined and powerful when standing at a certain spot about 10 feet from the front of the sub and lost those qualities as you moved away from that spot.  With the two subwoofers it is true- the room is equally balanced.  
With respect to stereo sub-bass it can come off as directional when the higher frequencies of a given note can be localized to a certain direction.  Although the corresponding sub bass "hit" is not directional within the room, the fact that the higher frequencies are directional tricks the ear into believing that the sub-bass is also coming from the same spot- e.g  powerful stereo drum work.  

@gochurchgo  I have them connected with high level speaker connections, which has sounded better on my particular amplifier than line out connections.  Having these connections (like my old JL Audio sub)  was one reason that I picked them

avanti1960:"@noble100 I agree about the directional cues when at the listener spot but while moving about the room, the sound of a single sub can change dramatically. I had a single sub previously and the sound was so defined and powerful when standing at a certain spot about 10 feet from the front of the sub and lost those qualities as you moved away from that spot. With the two subwoofers it is true- the room is equally balanced.  
With respect to stereo sub-bass it can come off as directional when the higher frequencies of a given note can be localized to a certain direction. Although the corresponding sub bass "hit" is not directional within the room, the fact that the higher frequencies are directional tricks the ear into believing that the sub-bass is also coming from the same spot- e.g powerful stereo drum work."

Hello avanti1960,
     Yes, a single sub is capable of giving good bass response at a single designated listening seat but this also results in poor bass response at numerous other spots in the room.  The traditional "crawl" method of optimally positioning a single sub in a given room results in it being placed at a specific spot in the room at which it will not cause any bass modes (bass peaks, dips and cancellations) at the designated listening position.  
     This very process, however, literally guarantees that there will be an abundance of bass room modes at numerous other specific spots in the room away from the designated listening position.  The relationship between the exact location of the sub in the room and the exact location of the designated listening position in the room is a very unique and precise one with a small margin of error.  In fact, it's very likely that there are bass modes very near to the designated listening position but not exactly at this position, so the bass response precisely at the listening position is still unaffected. 
     The above explains why you experienced poor bass performance as you moved away from a spot about 10 feet away from the front of the sub.   But I wanted to point out that adding a 2nd sub didn't exactly equally balance out the bass response in your room.  The actual dynamics are more complex and I'll try to explain it in another post when I have more time.
       It seems like you have a very good understanding about the fact that there's no such thing as true stereo sub-bass (below 100 Hz).   And you gave a fairly good explanation of the fact that we can perceive a form of stereo sub-bass with the assistance of sub-bass harmonics or overtones that reach into higher frequencies that we can localize (tell where the sounds are coming from) and our brains are able to associate these higher frequency sub-bass harmonics/overtones  with the much lower frequencies of sub-bass fundamental tones and thereby localize the instruments producing them.  This is one principle of what's termed psychoacoustics.  

Later,
 Tim