My speakers don't "dissapear"

Assuming you have not placed them on a table or bookshelf or against a wall or next to a TV (any of which can collapse the sound to the speaker), then you have a problem. Do you have an incorrect setting in your DVD player/amp (is it converting CD's to pseudo surround or something - adding a "stadium reverb effect" for example - also many players with DSPs have many options for sound processing like "all speakers" or "pseudo surround" and "two-channel stereo straight through - no proceesing"). If you have fully exhausted the DVD and amp DSP menus you should take the speakers back or investigate if you have a problem elsewhere.

Are your speakers wired out of phase?

Good one! Translation = "Is one speaker wire reversed from the amp to one speaker. I.E. Black amp post to Red speaker post on one speaker while the other speaker is properly wired with black to black and red to red."

Leave your door unlocked. It may take awhile but they will disappear forever.

Indeed - like the thread about the economy. It was erased and I can't find Macrojack's wise comments. Just like the $300 billion of taxpayer money that may get erased with the Freddie and Fannie mother of all private enterprise bail outs. It seems capitalism has become a ponzi scheme - when things go well and state assets are sold off (privatized) it helps make money for bankers but when things go badly wrong the taxpayer steps in once again to clean up (and banks are saved). Man this ponzi system of capitalism is great (if you happen to be on the right side of the gravy train that is....)

You might try stuffing something absorptive into that slot, like a thin slice of foam, or otherwise smoothing it over (maybe just a piece of masking tape would help - or better yet duct tape, for that macho look)

I wondered about that - it is an extremely odd design - like an acoustic "notch" filter at a specific frequency - I wondered if it is deliberately designed to reduce ringing from the metal tweeter....perhaps tuned at a specific frequency based on the depth - just like a tube trap or resonator only very small....

The living room is rather "live" so I should probably look into room treatments as well.

Tile floor - BAD
Coffee table in front of speakers BAD

I assume your home is brick block/concrete with reflective walls - BAD (these do not breathe and they will reflect all the energy back into the room - a claustrophobic cluttered sound)

=> you need acoustic treatments in a bad way unless you can accept that it simply won't sound like it did at the dealer even if it has the potential to do so.

Based on your last post you need acoustic treatment bigtime - if you can't aesthetically treat a highly reflective space then don't throw good money after bad with expensive cables, IMHO. You simply won't be able to re-create that great sound in the dealership. Look on the bright side... you live in Greece and while you are still enjoying the sun I'll be shoveling snow and freezing my %^$&'s off!!