Nasty slap echo


When i clap my hands it sounds like the ricochet sound from a WW2 documentary. I have panels on 1st reflection points but doesn't help. My room is 15x8x22, which are "supposed" to be good dimensions. I did have them drop the crown molding down 4 inches to put rope lighting up there. Was wondering if that is causing the problem. How harmful is this slap echo to the sound? Any suggestions?
streetdaddy
I have always the room was on the borderline of being overdamped. That is why i am scratching my head to this echo. Sounds like a "ping" that last for 1/2 second. Mainly at the front of the room. Will try to post some pics later tonight.
Streetdaddy, walk around the room clapping and you can pinpoint exactly the spot(s) where echo is concentrated. Treat this spot with something like the Room Tune pillows. You can make your own from fiberglass insulation and heavy duty aluminum foil as a temporary experiment. Adding treatment all over the place may be misguided and overdamp the room. Pinpoint the specific area and only treat there. Your "ping" is probably half way between corners at the wall/ceiling junction.
Agree with above posters that it needs to be addressed and can be mostly with furniture and etc. I am using bookshelves, thick carpet, rugs on the wall, fake plants, stuffed animals, basically anything to absorb slap echo. I too have walked around clapping or yelling profanities to reveal problem areas. Eliminating the reverb is especially important with rock and pop IMO due congested and compressed nature of such. Because that's mainly the crap I listen to, I have found new life in mediocre mainstream music.
Post removed 
here are some pics of the room....[IMG]http://i972.photobucket.com/albums/ae206/streetdaddy/DSC_2500.jpg[/IMG]