If you look at the value for 80 dB, you can see that ampdb returns the
correct result.  If 0 dB corresponds to 1 (10^0), then 80 db corresponds
to 10^(80/20) = 10^4 = 10000.  The manual is incorrect here, although
the difference is insignificant from the point of view of perception,
about 1% (0.2 dB).

Job van Zuijlen

luis jure wrote:
> 
> 
> completely apart from this, it's true that ampdb is _not_ very well
> calibrated; for 90 it returns 31622.8 and not 32000 as the manual says.
> below is a table comparing what i and real values given by amdb:
> 
> 90     32000        31622.8
> 89     28508.76     28183.8
> 88     25398.43     25118.9
> 87     22627.42     22387.2
> 86     20158.75     19952.6
> 85     17959.39     17782.8
> 84     16000        15848.9
> 83     14254.36     14125.4
> 82     12699.2      12589.2
> 81     11313.69     11220.2
> 80     10079.36     10000.0
> 79      8979.71      8912.5
> 78      8000         7943.3
>