# [SOLVED]Slope in db/octave

#### dwsmith

##### Well-known member
On a log plot in the x axis, if I have a slope of -6 db/octave from 100db, what would be the location of the new coordinate?

So the y axis is db and the x axis is in log.

First coordinate is $$(10^2, 100)$$ then a slope of -6. The second coordinate is $$(10^3, ?)$$?

How does one determine the y location?

#### chisigma

##### Well-known member
On a log plot in the x axis, if I have a slope of -6 db/octave from 100db, what would be the location of the new coordinate?

So the y axis is db and the x axis is in log.

First coordinate is $$(10^2, 100)$$ then a slope of -6. The second coordinate is $$(10^3, ?)$$?

How does one determine the y location?
A slope of - 6 dB/octave is equivalent to a slope of -20 dB/decade...

Kind regards

$\chi$ $\sigma$

#### dwsmith

##### Well-known member
A slope of - 6 dB/octave is equivalent to a slope of -20 dB/decade...

Kind regards

$\chi$ $\sigma$
Then $$(10^3, 80)$$, and if I had a slope of -12 following, it would be $$(10^4, 40)$$, correct?

#### chisigma

##### Well-known member
Then $$(10^3, 80)$$, and if I had a slope of -12 following, it would be $$(10^4, 40)$$, correct?...
Not exactly... $\displaystyle (10^{3}, 80\ \text{dB})$ is correct and -20 dB\decade means $\displaystyle (10^{4}, 60\ \text{dB})$, $\displaystyle (10^{5}, 40\ \text{dB})$, etc...

Kind regards

$\chi$ $\sigma$

#### dwsmith

##### Well-known member
Not exactly... $\displaystyle (10^{3}, 80\ \text{dB})$ is correct and -20 dB\decade means $\displaystyle (10^{4}, 60\ \text{dB})$, $\displaystyle (10^{5}, 40\ \text{dB})$, etc...

Kind regards

$\chi$ $\sigma$
You said -6 is -20 so wouldn't -12 be -40?