Sound Engineer's Pocket Book, 2nd Edition

30 Public Address Data

100 Volt Line Loudspeaker Systems

(Data reproduced by courtesy of Klark Teknik.)

Load impedance versus power dissipation
ohms	watts
10	1000
20	500
25	400
33.3	300
40	250
50	200
83	120
100	100
111	90
125	80
200	50
250	40
333	30
500	20

Load impedance versus power dissipation
ohms	watts
1.0 k	10
1.11 k	9
1.25 k	8
1.43	7
1.67	6
2.00 k	5
2.50 k	4
3.33 k	3
5.00 k	2
10.0 k	1
20.0 k	0.5
40.0 k	0.25
80.0 k	0.125

Absorption of Sound in Air for Different Relative Humidities (dB/30 m)

Note that peak absorption for all frequencies occurs between 10 and 20 per cent RH. The peak at 2 kHz occurs when RH is about 10 per cent; at 10 kHz when RH is about 20 per cent. ...