Is this situation detrimental to my child's learning? Also, can the sporadic (start/stop) band music somehow affect her behavior or her mood?
It's clear that very loud noise levels in classrooms can impair children's speech perception, reading and spelling ability, behavior, attention, and academic performance. Most studies that examine the relationship between noise and learning focus on the impact of very loud noises (like those made by jet planes passing overhead or trains passing outside the school).
These noises have a devastating effect on reading, speech, and auditory comprehension; they cause irritability in students, teachers, and parents who live and work in those environments. Some studies show that lower-achieving students are more affected by such noises than better students, but that few students (or their teachers) are totally immune to the effects of noise. Other studies show that loud noises increase the production of stress hormones that have the effect of making kids less efficient learners. Memory, in particular, is affected by persistent loud noises.
However, even interruptions caused by noises that are not as loud as passing planes or trains can certainly have an impact on how well children process auditory information, and on their attention and ability to focus on the important sounds in the classroom, such as the teacher's voice. In general, the teachers of little kids need to talk louder so that the children can hear them effectively, since children need speech to be about 10 decibels louder than adults do to hear the sounds correctly. This is because young children have not learned enough language to "fill in the blanks" they experience when a teacher or classmate communicates to them in a noisy environment. Researchers say that it is only when children reach their teens that their ability to listen in a noisy environment is as good as adults'.
Children with hearing loss, or whose first language is not the language of the teacher, those with language-based learning disabilities, or those who have recurrent ear infections are particularly at risk for distortions in hearing caused by background noise. Children with Central Auditory Processing Disorders (CAPD) are especially vulnerable to the effect of non-instructional noise.
School administrators and teachers need to be aware of the negative effects of environmental noise on learning. Attention should be paid to class schedules that minimize noisy interruptions. School architects need to consider acoustical design features, such as sound-absorbing wall and ceiling tiles, draperies, and carpeting that dampen non-instructional noise.