Small beautiful sound

Meanwhile, I have heard the CD several times. Because of the great arrangements, it is interesting. I'd the idea to publish such a CD, call succeeded. Try the performers but play great works from the operatic repertoire in chamber music ensemble. Just as brass one is not spoiled here, because there is simply too little original literature.
However, a point of criticism is the sound quality. So no sounds Brass Ensemble! The piccolo trumpet sounding very hard and uncultivated. Actually, this should provide some luster. That's here but did not succeed. The horn, the trumpets and drums sound too opaque, intrusive and therefore not properly heard. In addition, the tuba is often too loud.
I am not quite clear why. Perhaps the area in which the recording was made, not suitable or the sound engineers have no experience with the inclusion of brass or percussion. That should be "German Gramophone" but already the case with the label. Too Bad.