I'll bite and say the sig 805's, and for several reasons. First, the CDM9NT's do not go much lower than the 805's. Second, the 805 sigs. sound better. Third, they will be easier to place in the room. Fourth, they are easier to drive. Fifth, the CDM9NT has been replaced by the 704. And finally, you'll own one of the best loudspeakers made by one of the largest and most revered loudspeakers companies in the world.
On the upside for the 9NT's I'd have to say they go a little lower in frequency, have that very cool surroundless piston midrange driver, will play louder, and you might find them significantly discounted by some dealers.
What shape is your room? What kind of music do you listen to? I just awoke so I can't tell you the formula for finding the resonance of your room but look at it like this. Let's say that your room resonates at 47 Hz like ours does , then the 805's without eq will begin to roll off around 80hz and be 4 or 5 dB down at our rooms resonance. With the typical room gain around 28 Hz our the 805 signature would measure and sound more linear than the 9NT's in the bass because some of the peak resonance is removed compared to a speaker that goes flat down to that frequency. Now if you were to put the 9NT's in the same spot, that same 47 Hz resonance would ring like the dickens since the 9NT's bass response is flat to about that point. It might sound like better bass response, and it is in some ways, but measuring it and trying to fix it will make your hair fall out unless you add sometype of parametric EQ. I hope all this makes sence or it is one of those hear-me-now-understand-me-later things. Just remember to relax and have fun.
Keith
On the upside for the 9NT's I'd have to say they go a little lower in frequency, have that very cool surroundless piston midrange driver, will play louder, and you might find them significantly discounted by some dealers.
What shape is your room? What kind of music do you listen to? I just awoke so I can't tell you the formula for finding the resonance of your room but look at it like this. Let's say that your room resonates at 47 Hz like ours does , then the 805's without eq will begin to roll off around 80hz and be 4 or 5 dB down at our rooms resonance. With the typical room gain around 28 Hz our the 805 signature would measure and sound more linear than the 9NT's in the bass because some of the peak resonance is removed compared to a speaker that goes flat down to that frequency. Now if you were to put the 9NT's in the same spot, that same 47 Hz resonance would ring like the dickens since the 9NT's bass response is flat to about that point. It might sound like better bass response, and it is in some ways, but measuring it and trying to fix it will make your hair fall out unless you add sometype of parametric EQ. I hope all this makes sence or it is one of those hear-me-now-understand-me-later things. Just remember to relax and have fun.
Keith