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Reverse an exponential scale

March 12, 2010 | 9:21 am

I know that I can replicate the exponential scaling of [gain~] with [scale 0 157 0. 7.942307 1.071519]. My question is, what exponential value would I use to reverse that process? In other words [scale 0. 7.942307 0 157 ???]. Thanks.


March 12, 2010 | 10:22 am

dbtoa / atodb [?]


March 12, 2010 | 7:54 pm

I thought about that, but it’s not dB and amplitude. It’s that strange relationship between amplitude and 158 that is present in the [gain~] object.


March 12, 2010 | 8:42 pm

This should explain the [gain~] equation and you can see how to do the reverse to get you back to where you started.

lh

– Pasted Max Patch, click to expand. –

March 12, 2010 | 9:19 pm

Thank you Luke! That’s exactly what I was looking for.


March 13, 2010 | 1:29 am

i usually scale the range down to 0-1, reverse that, and scale it up again.


March 13, 2010 | 8:03 am

With the default parameter, there’s 6 dB for 10 increments. So it’s easy to find the value in db. It’s more or less the same patch as Luke, but you might get easier the 6db per 10 ints by not including the dbtoa conversion in the expr.

– Pasted Max Patch, click to expand. –

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