B&W CDM-1NT vs 7NT vs 705

[Rhino]

The 7NT is nice but a sub may be cheaper to integrate and may offer more depth...however one sub does not create a proper stereo image and can sometimes be difficult to integrate into the room.

Doesn't this depend on the cutoff you use? I thought for low frequencies the human ear couldn't distiguish placement (directionality). If you've got your cutoff set high, then perhaps imaging could be a problem but I've got a single sub on my sytem and yet get terrific stereo imaging.

[RGA]

No because you have one woofer producing what two is meant to be producing. There was a small write-up on this in UHF mag a few issues ago and was discussed not too to long ago on Audio Asylum as to why 2 subs would be more desirable than one for music playback. Presumably if the sub is used as it was MEANT to be used which is to be SUB, or below the audible bass frequencies ONLY then one sub would probably be ok as it is then being something used to be FELT not heard.

However, most subwoofers are actually just woofers and they basiclaly create sound sometimes up to 100Hz or basically replace the job of a woofer.

Indeed, if you take a full range speaker system and the disconnect the the woofer(s) in the left speaker and feed the signal in the right only you would have a directional problem.

Using Wilson Watt/Puppy as an example. The Watt is the standmount section that can be purchased separtely and the bottom section is the subwoofer section called the Puppy. There are two, not one however. Reference3a, Gershman Acoustics among others have these kind of set-ups...

Now how anal you want to get about is another matter and the good thing is you can always add the second sub later on which was the case many single sub owners made. And of course some subs are better than others(as well as room acoustics and set-ups).

[Rhino]

"A true subwoofer can be set up in mono, since the wavelengths associated with these frequencies are so long that not only is the ear insensitive to their directionality, but a single wave would not even fit inside a typical room without reflecting several times to do it."

"The Dolby surround signal is a mono signal usually fed to two speakers located towards the back of the room. This signal is unique in audio because it is rolled off at 100 Hz. This doesn't mean that there should be no deep bass in the ambience effect. It does mean that the deep bass is generally understood to have no directionality. Our head is too small, our ears too close together, and our hearing too insensitive to be able to tell which direction low frequency sounds are coming from. Remember how no one worries where the subwoofer is placed, except for visual or room mode control? That's because we can't tell where the bass is really coming from." --Home Theater Magazine

You can buy two subs if you want, but I think spending your money on one really good one makes a lot more sense. Like I said, I use one sub and have a system with terrific stereo separation and imaging. If you've got speakers that roll off above 100 Hz maybe two subs would be a good idea, but mine start to roll off at 60Hz and that's where my cutoff is set. Like the article says, there's no way you can anyone can tell where those low frequencies are coming from.

[bodiniusz]

So, any thoughts after 10 years?

Now I am thinking of upgrading my CDM1SE and have the choice of 705 or CDM7NT. Please help with decision