hello csounders,
i thought i didn't have much to-do with my time this night so i decide to read stuff about sound and then i discovered phon & sones
someone can explain like i'm 5 why this metric isn't added to csound? or decibels are just the same thing? like miles vs. kilometers?
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Hi Lucas,
maybe there’s a bit of confusion between all of these concepts. Let’s see:
1. The decibel scale is a linear scale for amplitude ratios. 6dB change is nearly doubling/halving amplitude.
2. Using the dB scale, we can set up some absolute amplitude scales, but these are created with a given
reference, e.g.
- 0dbfs scale: the reference is the max amplitude before clipping
- SPL scale: the reference amplitude is the threshold of hearing at 1 KHz.
3. Phons is a measurement of perceived equal loudness for sine tones, which is equivalent to SPL at 1KHz
and follows the equal loudness contours as defined by an ISO standard. Sones is a similar measurement but
not equivalent. These can are not normally used directly in measurement of loudness, but they form a framework
for it.
4. There are well-defined loudness measurement schemes (such as dB(a) etc amplitude), which apply a filtering
of the signal to improve the perceptual dimension of the measurement. A common measurement standard is LUFS,
which seems to be used widely now (e.g. streaming services use it to control content loudness). We have this,
https://csound.com/manual/lufs.html
Hope that helps
Of course I meant
" These are not normally used directly in measurement of loudness, but they form a framework
for it.”
on item 3
.. and there is the sone gen
Like ampdb( ), it would be nice to have an amplufs( ) value converter in Csound7 and other amp converters being discussed here by victor - essentially, a comand-line option or a way of setting an output or bounce to “normalize” to these various amplitude scaling systems (for mastering and distribution and live performance). Maybe we have this already?