| Abstrakt: |
An intermediate frequency tweeter placed high above the rostrum and fed with frequencies 1000 to 10 000 having correct vertical and horizontal angular distribution beamed on the audience and not on walls and ceiling will crisp up consonants without adding to reverberation. Kuhl recently found (by tape recordings to eliminate prejudice) that optimum reverberation of concert halls for symphony music is 1.6 to 2.1 sec independent of size, contrary to the usual idea that it is proportional to the cube root of volume. Two seconds also is probably optimum for churches when full and adds much to inspirational effect of both the music and the sermon. For plays it is desirable to have a reverberation of under 1 sec to avoid overlapping of syllables, but in a sermon the speech is much slower so that 2-sec reverberation usually does not blur the words. However, for the occasional fast-speaking minister, the above P.A. system will make the speech quite audible despite long reverberation. Even plays can be put on if several microphones are distributed along the front of the platform. A 10-μf condenser should be put in series with the speaker to protect it from accidental frequencies below 1000. [ABSTRACT FROM AUTHOR] |
