Shama-il Tirmidhi Chapter 043, Hadith Number 008 (304).

Ibn 'Abbaas Radiyallahu 'Anhu says: "Rasulullah Sallallahu 'Alayhi Wasallam raised his voice only to the extent, that it might have been possible that if he recited in the house, those in the courtyard might be able to listen".

Commentary
The voice did not reach beyond the courtyard. The reciting of the Qur-aan softly and audibly are both better according to the circumstances. On a correct and suitable occasion, or where for a reason it is desirable to recite audibly, there one should recite audibly. If there exists a fear that it will create show etc., there one should recite softly. The object is that according to circumstances it keeps changing, therefore, Sayyidina Rasulullah Sallallahu 'Alayhi Wasallam has said the one that recites the Qur-aan audibly is like the one that openly gives sadaqah, and the one who recites softly is like the one who gives sadaqah secretly. Concerning sadaqah, at times it is better to openly reveal the giving of it and at times it is better to conceal it. Circumstances should be taken into consideration, which change from time to time. This rule applies to the reciting of the Qur-aan also.