Convert CC value to dB

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richdrich
Posts: 14
Joined: Tue Jan 08, 2008 2:14 am

Convert CC value to dB

Post by richdrich » Tue Nov 24, 2009 4:40 am

I need to know how Ableton converts a CC value (0-127) to a dB value (-infinity => 6dB).

I've looked at a few test points by feeding values from Max into the volume control, but can't work out what the function is.
I want to make the volume (along with bass, treble) for a track dependent on some inputs, and to do this I need to process these numbers.

LOFA
Posts: 3365
Joined: Mon Jan 10, 2005 7:10 pm

Re: Convert CC value to dB

Post by LOFA » Tue Nov 24, 2009 5:02 am

How about something like this?


<pre><code>
----------begin_max5_patcher----------
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yfF4bPqI.D1dMEvPMrqep0+wExfTCNsfSvk79SUZbNGbiPtC3W6mv.TH00M.
NWJ4ibAq1dt3zQ8Bof+tPZnSST1FheDhrTmlPVzDvd6CSz+EOKUkKx3k+47Q
tJVWuxGNp6tW83aWTVl079Q1L5z9sMaIxhunWTpsXVxLtRfbYVnmh4NzMBLZ
hQauJuqOaAM6JUEyrjFWZW6YfnyUNSv+ckyHjyHotMThqsI76P4zWtT5CdRS
XBL1kJVgXiZ9huKvZEy3OGUUpikosqVSU8fS1IiWoExXsn9iFN8Ll7tcdn6E
YYbY22h0v8fpVaMZXf2aiURlhi.32PSau9RZTXBe0zTzXjj+zvDAwLks5xeR
nAsctT7gFgVillTwXq5nMe4Jqsy0Ppzo8htQp0IlYtp2Z5bgRkMlC.noQUlU
oXlsZbLhzSOWPPmkvnKG3ivEroYBpukvglVmgL+9EwMW8zpeCv2.suF
-----------end_max5_patcher-----------
</code></pre>


MInd you, I am drunk, and merely taking a break from trying to organize all of this new api lingo

richdrich
Posts: 14
Joined: Tue Jan 08, 2008 2:14 am

Re: Convert CC value to dB

Post by richdrich » Tue Nov 24, 2009 5:42 am

Yeah, but I think that assumes that the dB is a linear function of the CC, which it isn't.

LOFA
Posts: 3365
Joined: Mon Jan 10, 2005 7:10 pm

Re: Convert CC value to dB

Post by LOFA » Tue Nov 24, 2009 5:51 am

I think there may be a variation with the live.knob or live.slider, but I haven't gotten there yet.
Perhaps a scaling preference.

This will control a master fader:

<pre><code>
----------begin_max5_patcher----------
775.3oc4W90aaBCD.+YxmBKdlFgAL+Yuso8Rk19DLUU4.NotCri.mtrU08Ye
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LIu5dMcI94dhwbT9AVX6.r2fY6rA2nF1SqVoZbFIJXjeHM2F8JHG0tpsbgyJ
HUU.IEtCjSefbaEQ.JvUBR4shRb52AEzixmyHOPSIfG34GjtSWH0aHjFDogI
zW056AU+441CSQSjociSXe3bYInjYqUza1LIvSGlgFDIgKBR76EIN0+VbzTR
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.Gh.nD8tEnI.IxHjzMAhZq6TdNuzrFtq8cTMApVYCr0zmRFKv0BbNMsGj0L2
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NXfOz8ewSjLXUmsk7hYV2Qik.cLP7P0bB+uqlCkM8RNdlC1gZkksmDJvkqfS
uQZTY7xITQaHxipwd4Uqzthp+SQUE+PYZyp0bCHvy9SFoRPYXAkyZOHuSFzc
zrLBq8mQIc2ykFWsQ3IqSib.IF1kDclfY+pebRiPOepGqWDOFmHYZNwEZRpj
NupMEOMSRcvGIv7CMY6PMBWnohFgk9B24UMUj1RgH8UEgtdcH41bVtZg2BfK
q5CfSF3xRpJaLHoQ3RM0QXonowa+.sso2cYXu54KzN8GSjg5xsug6qzpCNlD
VvYZSRgmV8G.+rJRyA
-----------end_max5_patcher-----------
</code></pre>

LOFA
Posts: 3365
Joined: Mon Jan 10, 2005 7:10 pm

Re: Convert CC value to dB

Post by LOFA » Tue Nov 24, 2009 5:52 am

Right. THe operative word being cc. Hmmm.

richdrich
Posts: 14
Joined: Tue Jan 08, 2008 2:14 am

Re: Convert CC value to dB

Post by richdrich » Tue Nov 24, 2009 6:12 am

Also, the raw values from a control in the range 0-1 (which *are* linear to CC (1/256th in fact).

jayemell
Posts: 95
Joined: Wed Nov 18, 2009 6:05 pm

Re: Convert CC value to dB

Post by jayemell » Tue Nov 24, 2009 7:37 am

Would this work for your purposes?
Goes beyond 0dbFS.

jml

<pre><code>
----------begin_max5_patcher----------
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aAuojd5omy22OJkC1VvHwdZID7H3Efk0AaKKcHU.KybKXV393zvRcZv2RE7p
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exYAMznn4pdVo1kIQm3nxHHDQLWtFbQ2Q2d.6gYe.KXFmu5CQcufoL9u+CmV
up38IaonpHtsTsut.+H4DZojw0.qaR3dIsikjP0q2B5LVRtfwkFQLx64IqI7
Tzj6xpoIwIukUStSPSAKpjBlBkHWfjpmbz9akG6P2A
-----------end_max5_patcher-----------
</code></pre>

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