[SwanSong]

Any thoughts or experience with a dual sub setup?  I know the first recommendation will be A8" but I want to control bass levels and keep a tight clean blended bass line.  I will keep bass db as low as possible to achieve a LF extension, not a sub bass sound.  The monitors will be in high pass mode to reduce monitor LF workload.

 

[plantsman]

In terms of compensating for the room the more subwoofers the better (see Duke LeJeune's/AudioKinesis swarm subwoofers) provided that they are carefully placed.  As far as the localization issue goes that should not be a problem if the subwoofers are crossed over low enough.  The x-over slope(s), the characteristics of the room and the bass performance of the main speakers all come into play here but if pressed to generalize I would argue that the hinge point of the low pass filter should never be higher than 60Hz and preferably is significantly lower than that.  With small monitors you can often get a situation where you have relatively smooth and continuous bass response (room effects make really smooth bass response a largely unattainable goal) but a lack of bass energy in the midbass, the system lacks punch.  Trying to fix that by raising the low pass point generally creates more problems than it solves.  I think this could be a problem with the Adam 5X/Sub7 combination.
 
Short answer: stereo subwoofers are better than a single subwoofer but they aren't a magic bullet.
 
The Adam Sub7 appears to be more of a woofer than a true subwoofer and it seems to permit what I regard as unacceptably high crossover points.   I have not, however, used this particular combination although I do have experience with subwoofers from REL, Vandersteen, Entec, RH Labs, Janis, Wilson, Gradient (more of a dipole woofer actually),  Sunfire and Velodyne.

 

[SwanSong]

Thanks for the feedback! Yeah I think the a5x starts falling off at about 70hz realistically. Also I think your right the sub7 is more a bass woofer than sub so I was thinking of using the high pass at 85hz and blend from there. I think that would enable the sub7 to have assume more of the stereo signal vs just the mono sub LF. Is it true that most LF are mono for the most part?

 

[plantsman]

With vinyl sources low bass has to be mono or it could throw the stylus out of the groove.  Digital sources offer the potential to go lower without summed bass but the decision to have mono low bass may be made for other reasons.  I don't entirely agree with the conclusions of this paper based on my own experience but you might find this interesting http://www.acoustics.hut.fi/research/cat/psychoac/papers/kelloniemiaes118.pdf  In addition to the crossover frequencies the spatial relationship between the monitors and the subwoofers, the listening position, the room, source material and the size of the woofer enclosure all influence how localizable the subwoofers are and to what extent they sound like separate discrete sources.
 

 

[Lolito]

So, 8 years later, what sub you bought? sub 8?

I also like the idea of dual sub 7 rather than a sub 8; the sub7 has bypass pedal switch option possible, sub 8 doesn't... Also sub7 is cheaper, so you can do a dual sub setup cheaply...

What about the down firing adam t10s? what do you think about that option from adam? it has foot switch option, no remote or front controls though... 10" 140W