# What is the rating on a curve

## Planning and construction of a soundproof rehearsal room

### Evaluation curves

Based on the curves from Figure 3.1 Simplified frequency weighting curves were developed (Müller / Möser 2004, p.113).

The calculation formulas for the A and C evaluation depending on the frequency can be found in DIN EN 60651.

You can see that our ear perceives more “linearly” with increasing volume. As a result, for example, the hearing and pain thresholds are closer together at very low frequencies than in the kHz range.

As shown in Figure 3.1.1 can easily be seen, curves A, B and C differ mainly in this low frequency range and should be used depending on the level of the signal to be evaluated. The A-weighting is similar to the curves of equal volume at 40 phones, the B-weighting to that at 80 phones and the C-weighting corresponds to the 100-phone curve. However, the B-evaluation no longer has any real significance (Müller / Möser 2004, p.113f). The others in Figure 3.1.1 The curves shown are not relevant for the construction of such a space as I am describing it here. The D-evaluation was introduced for aircraft noise and the U-evaluation for the measurement of auditory sound with simultaneous occurrence of ultrasound (ibid).

The phon curves can therefore be used to determine whether two sounds are equally loud. With the help of the loudness, which is specified in sone, the perceived difference between two sound signals can also be assessed. It was determined that 1 sone = 40 phon. Every (subjective) doubling / halving of the volume corresponds to a doubling / halving of the sone value. The relationship between the volume in Phon and the loudness in Sone is not entirely linear (Müller / Möser 2004, p.84f).

For the sake of completeness, it should also be mentioned that in practice methods are used that can calculate the loudness to a good approximation from measured spectra (Müller / Möser 2004, p.110f).

The assessment of the noise effect is not fully developed.

"For example, with the same sound pressure level, the effects of sound with a clearly protruding single tone are quieter than broadband sound, but experience has shown that they are perceived as more annoying."Müller / Möser 2004, p.111

In general, it should not be forgotten that acoustics are always about perception. Different people perceive stimuli differently. Not only because they may hear differently, but also because they perceive the same sound differently due to different experiences and tastes. Of course, there are also sound events that are so loud that they are simply harmful to health (Müller / Möser 2004, p.91). But noise starts earlier in terms of level technology. Those who are hard of hearing speak louder than other people might like, visitors to a party will think differently about the loudness of the music than their neighbors who have gone to bed, and when a quiet instrument is being recorded, ventilation noises that are barely audible can easily be described as annoying noise become.

"Your own dog doesn't make any noise, it just barks."Kurt Tucholsky