Develop song to develop tissue, not other way around. When you concentrate on the psychology of breath anatomical structures will take care of the physical activity needed to do the job. Most actions we perform are too complicated to think about. Chicago Symphony - plays as loud as theY do because the acoustics at podium. Brass does not sound as loud at podium.
Acoustics can effect sound, tuning and matching of sound.
Finest quality of tone in the midrange leads to better quality at loud and soft dynamics. Motivation of player influences sound, tuning matching most. Continue long tone. Positive approach to playing music. Imitation and Creative Thinking are two most important tools.