Can I suspend / hang speakers?

The speaker cabinet will indeed move in response to the cone and this movement will be quite small by daily human standards. However, this small movement IS in my view enough to smear the sound. I cite the same reasons as others on this thread for rigidly mounting speakers to stands.

Given that woofer cones are generally made to be as light as possible and that the reverse is true for speaker boxes, the reaction movements of the box are indeed very slight, but not in my view insignificant.

Bottom line is that this system is for "dad" who is not likely an audiophile, else he'd be setting it up himself. With some folks esthetics, convenience, whatever far outweigh imaging, purity of tonal balance and the rest of our arcana.

My advice is to make sure that the system is safe - the hooks have adequate safety margins, the cables don't get tangled with the raising/lowering, etc. - and then let your dad enjoy it.

The positive aspects of suspending speakers are complete mechanical isolation from the floor (so that it doesn't vibrate) and removal of the speaker from all adjacent surfaces. (You would not, for example, put the speaker right next to a side wall).

As to speaker movement...in addition to being a tiny force applied to the massive enclosure, it is at the wrong frequency to induce "swinging". The pendulum frequency of the suspended speakers will be lower than one Hertz, and no loudspeaker goes quite that low. Finally, musicians do not clamp their instruments into rigid mounts as they perform, and neither do audiophiles clamp their heads when listening. The instruments move about at least several inches, so I can't believe that tiny speaker movement is would be a problem.

As always, those who have not tried the idea are on thin ice when commenting. For cosmetic reasons my speakers are not suspended, but I have heard excellent results from suspended setups. In fact, many years ago I heard the original Bose speakers hung about six feet in front of a brick wall in a warehouse with a ceiling of about 20 feet. You would not believe how good they sounded. I have also heard Maggies hung near the middle of a very large room with high ceiling. Also superb.

This thread seems to have just about died - but in hindsight it looks like a Michael Moore film: Lots of itty-bitty factual pieces taken and spun to support the outcomes each of us are after.

For my closing remarks on the physics of this situation - the system will certainly be enjoyable to even the most prudish audio nut provided at least most of the other considerations are taken into account. Just as the poor electrical/vibrational/speaker positioning environment doesn't preclude us from enjoying music in the car, the slight change in rigidity due to suspending speakers do not prevent people from enjoying the stereo system.

I do have to disagree with the statement by Eldartford regarding...
"The positive aspects of suspending speakers are complete mechanical isolation from the floor (so that it doesn't vibrate)"
The speakers are not isolated from the floor - and this is not in reference to an abstract and academic concern regarding the inability to achieve "complete" isolation as cited above. The suspended speakers are simply another coupled element in the system although the speaker supports (chains?) have the unique ability to have no meaningful compressive load resistance, this does not mean the element (speaker) is isolated from the rest of the system.