Ceiling.. to much absorption

hello.... we´ve managed to get a really good frequency response in our control room. Anyway there is a problem that the complete impression at listening to music seems to be a little dull. We´ve treated all ER-points generously with some bigger porous absorber; especially at the low ceiling (2,5m height). All of them were covered with a thin plastic foil to keep some high reflection. All absorber-surfaces were angled to get a RFZ for the reflection of the highs. The ceiling absorber is 8" thick. At the rear wall is a bass absorber and there is no more longer modal ringing. Could it be a problem that there are some dull reflections (omnidirectional) from the ceiling in the lower frequency range, that will make the soundimage dull. Also my voice under the cloud sounds a little dull although there is a foil. Could that dull reflections be the problem? RT 60 looks really regular and even at 0,2s. Perhaps could also the short reverberation time be the problem? The room dimensions are 5x6m. thx for you help.