calculation question...

[3dot...]

if say..
I want to add 4 dB to the current tracks' volume position...
how do I scale the dB value >> to the linear (0.- 1.) scale that the 'mixer volume value' accepts/observes ?

[r_v]

multiply by 1.58489319.

10^(4 / 20) = 1.58489319


to convert log value x to linear: 10^(x/20)

to convert linear value x to log: 20*log10(x)

[3dot...]

hmmm. thanks..and sorry I'm a bit thick..
but..this doesn't work for me..

the slider value observed is 0.85 (at 0 dB)..
multiplying by that number goes over the 1. limit of the range (it's supposed to be 4 dB no ?)
0. - 1. is supposed to scale -70.dB to 6dB..
please help

[pid]

you might want to check out the [dbtoa] and [atodb] objects which do this for you.

however, there is confusion here. scaling linear amplitude (0. - 1. - +++) is easy. however, you i think are talking about 'normalised value' which live will spit out. if dealing with the right hand outlet of a live.* object this is easy of course, but if you are dealing with a queried value then it is more complicated. sometimes impossible, depending on if that queried value is scaled linearly itself or some other scaling factor. it seems like it is not scaled linearly, as you say 0.dB is 0.85, whereas as in that scenario my maths brings it out (linear scale) at about 0.92...ish. also, remember, -70.db does not equal 0. amplitude!

sorry not to help more. case by case. probably more info needed to work out.

[3dot...]

pid... once again your are right (about everything)

(sorry I've missed the whole high-school "experience")

how can I deduct the scaling value where :
----------------------------------------------------------------
1. = +6dB

0.85 = 0dB

0.55 = -12dB

0.001154 = -69.5 (the last value displayed in the live gui..anything below displays as -inf)

0.000112 = -69.95
(shown in live as "-inf" although you can enter the value in the box..
and as m4l api shows.. the value is accepted)

strangely enough -69.99 value shows '2.24296527449e-005' ..that's friggin weird !I'm guessing a bug ?

0. = -inf (is what I meant to represent with -70.0..)
-------------------------------------------------------------------------

I want to "watch" the volume slider.. (0.-1.)
get the REAL dB value of the volume..
and add/subtract from it in dB
(then convert the number back to 0. -1. range..back to the slider)

I'm stuck at getting the real dB value of the volume slider..

thanks again for all your help guys ... hope to find an answer to this..


<pre><code>
----------begin_max5_patcher----------
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xeskYgPX3f6NBivHKbfI5ALzvHxGJiDrmTt3aQTaNsjAfQ.TDXVpZjn+63Li
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LQt0nsJ51gd+2oTN6lqHSXgiYBoNsMM+1pk6P87rAi.60dwz7EH2vaWVv1yy
YfbpnVvUserbKsQAPPE+.qoW695xcUCulRtfkWuSHOgVWtiNniaStcj66e1T
1vh2ejvB+r+rlI+WczLJcQtVrh.8YwJ6piSlf1rOKdgQX7UbLvTcSj4XaKmX
xjcSjyeaMbj5bkzjrwy5icmdS0cRRf172L3.8hS8R2FTYcwJ2O+hjFNo4fcA
Xyyt4ifrOfIj30ejDyxpU7Jv0VuqIu2L6urJ3nktf0J4BSQqimkJ4CfFl0Fd
QASbx2CohWrslKjcVB3wyue5rwouenCF2qbgOUFW5mYxoC48.4zsf3.4V3ms
0Tmh4f9gbHmHWleHGwIxg7iws3z7vyPNh+HGxosUOTJIyoXNrWHGworUc2O+
mjSKPM7WiTsdzA
-----------end_max5_patcher-----------
</code></pre>

[broc]

Here is a related thread with "solution".

http://forum.ableton.com/viewtopic.php? ... ogarithmic

[3dot...]

Here is a related thread with "solution".

http://forum.ableton.com/viewtopic.php? ... ogarithmic

hmm....
I'm guessing this is the only current "solution" ... ?

stephan 'sampled' the values... it's not ideal...
thought about doing it.. but decided not to..I want to be as precise as possible

but how to get to the real scaling function ?

Ableton programmers maybe able to chime in with the actual function ?

this is one of those things again...
why do I hit walls for seemingly trying to achieve simple tasks in m4l?
(rhetorical I think..)