Background noise

The best known reason for poor speaking reception is bad signals due to noise conditions, that is to say exceptionally loud background noise.

Even though it is only proven for serious cases of noise existence it is logical that
this has a direct influence on speech reception even in the case of low levels of background noise.

A speaker's normal speech level is approx. 60 dB, measured at a distance of one metre, even though literature in some cases suggests that teachers talk with raised voices at approx. 70 dB.

It is obvious that to achieve reasonable noise conditions, even in small classrooms, background noise must be low.