Forums > MaxMSP

scale of the meter object

November 22, 2011 | 5:38 pm

Hello all,

I’m stuck on a problem that has been driving me crazy all afternoon. Hopefully someone will have come across this before, as it seems to be a rather simple issue, but I just can’t figure it out!

Here is the thing: the response of the meter object doesn’t align to a linear scale. That’s hardly a surprise, because of the logarithmic conversion required by the dB scale. Problem is, I can’t find a way to reproduce that same conversion anywhere else in Max. I want to be able to feed a slider with values in a way that corresponds to the display of the meter. Say the meter is right at the middle (6 LEDs out of 12). I want to know how to convert a linear scale (1-100 or whatever) into values that, fed into a slider exactly the same size of the meter, will drive it to exactly the same position.

That’s probably a very complicated way to phrase something way simpler, but I couldn’t come up with anything better. Hopefully the patcher attached will make it obvious enough!

What I’ve tried so far: atodb/dbtoa, scale using the 5th argument for exponential base, and more recently linedrive. This last one seemed very promising, but I couldn’t find a 3rd argument value that corresponded to the way the meter behaves.

Any replies will be extremely welcome!

Best,
Felipe

– Pasted Max Patch, click to expand. –

November 22, 2011 | 10:01 pm

If you look into the inspector of meter~, you can see how its translated. A bit voodoo with atodb should make it work. But I would skip meter~ for live.meter~…

– Pasted Max Patch, click to expand. –

November 23, 2011 | 12:02 pm

Hello Stefan,

Thank you loads for that, how did you come up with /3 +20 ?? Pardon my rookieness…
Also, any particular advantages of live.meter~ over meter~ ?


November 27, 2011 | 6:09 pm

Well, the inspector tells me its 3 db per step…
The advantage of live.meter~? Look at it…
And it will also show low audio levels, and its even eats less CPU cycles.
I’d turn the question around: do you know an advantage of meter~? I guess the only one is the possible bigger size…

Stefan


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