The relationship between tr/pr and lth

[XingdaChen1996]

If the prominence ratio is less than the lower hearing threshold(lth), does it mean that it is inaudible? But when I called the pr_ecma_st function, I found that the output pr was smaller than the lower hearing threshold(lth)

[XingdaChen1996]

I think it would be better to use tnr value less than LHT as a filter condition.

[wantysal]

Hello,

Thank you for this interesting question !
The prominence ratio (or tone-to-noise ratio) quantifies the ratio between a tone and the surrounding noise. Consequently, the value delta-t shouldn't be seen as an absolute dB value of the tone, but as a relative value between the tone and the noise. That is why its value can sometimes be lower than the hearing threshold. This comparison makes no sense, but if you want an idea about how much the tone is proeminent or not, you can use the prominence option to return only the significant tones.

I hope this is clearer for you ?

Salomé

[XingdaChen1996]

Thanks for the answer.
But I still have the following questions
i)
I saw this chapter in ECMA TR/108 (page 6), which is about calculating Total TNR and Total PR.

The TNR and PR inside are compared with lower hearing threshold(lth)

ii)
As a filtering condition, delta_t >0 I found that it is different from the results of matlab's built-in function. matlab's delta_t has a tone-to-noise ratio that outputs less than 0. Why can tone-to-noise ratio only output values greater than 0?