Hello Alexandre,
There is an instructive figure on the Wikipedia page for "Equal-loudness contours." https://en.wikipedia.org/wiki/Equal-loudness_contour#/media/File:Lindos1.svg
This shows dB SPL (re: 0 uPa) by frequency for a pure tone / sinewave input. If you want to convert a given dB SPL to its phon level you should take care to ensure that your filter weighting matches with your norm reference for phon level (i.e. A-weighting etc etc however the phons were obtained). See also ISO 226.
Interpolation between phon levels is likely not linear as well. Note that phon levels are a perceptual based scale of "loudness," which itself is the perceptual correlate of sound intensity (a physical measurable quantity in air, typically dB SPL.)
Because this unit is perceptually based, and is predicated using pure tone presentations at 1 kHz, you will get different results: 1) when using third octave or smaller bands (due to critical bands in hearing and nerve signal summation at the brainsteam and cortex), and 2) with time varying or modulated signals (such as the ISTS).
./d5
On Tue, May 28, 2019 at 12:22 PM Alexandre Torres Porres porres@gmail.com wrote:
just to be clear, I meant convert from dB to phon by also having a pure tone frequency as the input
Em ter, 28 de mai de 2019 às 14:02, Alexandre Torres Porres < porres@gmail.com> escreveu:
Hi people, I'm looking for an online resource or some piece of software that would allow me to convert intensity levels in db to perceived loudness in phons... anyone? cheers
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