Thank you Pierre for your response!
I got confused seeing exp instead of log..but now I got it! Thanks!

Another question that I have, is why pure data assumes the useful range is 100db..I mean, if I have let's say an audio interface with a dynamic range of 94 db, should this number matter the RMS formula?

Hi all!
I am into a project that I think I have to understand what is inside [dbtorms]. Extended shows that the formulae is:

RMS = (exp((2.302585092994 * 0.05) * (db_value - 100))

but i cannnot figure out how this formulae is derived..

any ideas?

thanks!

Hi! i have this pd procedure that uses two arrays.
The first array, the fre_array, is a array that stores 35 frequency values (from 200Hz to 10KHz) and the second array, the amp_array, stores 35 amplitude values. My goal is to plot a frequency vs amplitude graph.

To do that i use tabwrite in a new plot_array.

The right inlet is fed from the fre_array while the left inlet is fed with the correnponding amplitude values.
Since the indexes of the plot_array are actually frequency values that span between 200 to 10000, it make sense to resize the plot_array to have a size of 10000.
Although I think the graph is theoretically ok, i am unable to see it. This is because plot_array has only 35 non zero values in a total of a 10000 indexes array.
Can you share your thought on this? am i doing something completely wrong?