NOTE 1 For items with test frequencies over than 2 Hz the r.m.s. levels shall be lower than those quoted above. NOTE 2 For items with test frequencies less than 150 Hz the r.m.s. levels shall be lower than those quoted above. NOTE 3 If frequencies above f2 are known to exist they may be included, the amplitude being established by extending the 6 dB/octave decay line until it intersects the maximum frequency required. In such cases the r.m.s. levels shall be increased.