Thread: Musician needs help on getting a formula based on Ableton VolumeMeter.

1. Musician needs help on getting a formula based on Ableton VolumeMeter.

Hi,

Since I'm a musician and dont know that much about mathematic things I need your help!
I'm looking to find a way to get a formula (third degree equation?) based on the following data.
I need a formula because I want to use it in a max/msp environment because the input X needs to change to a Y but its not linear.
The VolumeSlider can only get 0.0 - 1.0 in but needs to move the slider to the corresponding dB place (-70 till +6dB).

(image of Ableton VolumeSlider)

I have some 'snapshots' of corresponding data and plotted them in a graphic thing. (see screenshots)

(table 1)
 VolumeSlider (0.0 - 1.0) VolumeMeter (-70 - +6 dB) 0.000 -70 0.035 -60 0.104 -48 0.187 -36 0.238 -30 0.302 -24 0.400 -18 0.550 -12 0.700 -6 0.850 0 1.000 6

But because of the conversion IN the VolumeSlider I also need an OUT conversion. Which is a flip of the above data. (I subtracted -6 dB of all the VolumeMeter because of some sort of offset in maxmsp function window. Couldn't specify a range between minus and some plus above thing. Random).

(table 2)
 VolumeMeter (70 - 0 dB) VolumeSlider (0.0 - 1.0) 0 1.000 6 0.850 12 0.700 18 0.550 24 0.400 30 0.302 36 0.238 42 0.187 54 0.104 66 0.035 76 0.000

But I want some sort of formula based on these two tables so I can use it fluently. I need some sort of "best curve fitting" thing of "trendline" based on these two tables.
Hopefully you guys can help me out!

2. Re: Musician needs help on getting a formula based on Ableton VolumeMeter.

This

interpolate &#40;0,0&#41; &#40;1,1&#41; &#40;2,5&#41; - Wolfram|Alpha

shows an example which might be useful.

You will probably get good results using 4 or 5 of your points. Just experiment and see how well it works in practice.

3. Re: Musician needs help on getting a formula based on Ableton VolumeMeter.

thanks for giving me a great website for using this stuff. nonetheless it gives me an idea of a good representation of a formula.
here are some results.

but how can i use this thing. it gives me a 'bumb' between the 0.8 and 1.0?

(click here for original data from wolfram)

4. Re: Musician needs help on getting a formula based on Ableton VolumeMeter.

Glad to see my post was sufficient to get you started.

The point about using fewer points is that will get a simpler polynomial and the results will I suspect be indistinguishable to our ears.

Edit: I missed your comment the 'bump'.

You could add a suitable point at 0.9.

Just play around with it. Add points, leave points out. Find out how few points you can have and still get a good
result.