dutchbastard

Midi VU Meter

6 posts in this topic

Hey,

this is my first post here (although i have been lurking for some time) and hopefully i placed it in the right section.

So this is my problem:

I'm planning to make a midibox64 and so far i understand how all the modules work and what they do.

However in my design i want to make a VU Meter. (If you don't know what VU meter is, Click)

So a VU meter basically measures the power (in Ampére?) coming in and lighting the leds up corresponding to the power coming in.

However i want to make one that works on Midi inputs, because Traktor (software i'll be using) sends out a midi output with a certain velocity.

Now i want to make a VU meter that works on those Midi outputs of traktor.

So far i have thought of this:

PC > Core > AOUX module > Leds

#1: Would this work?

#2: Would i need to create a VU Meter of the AOUX module or would i need to add the VU meter as a sort of module for the AOUX module (PC > Core > AOUX module > VU meter > Leds)

#3: How would this limit me in making a midibox 64. According to this schematic i can have DOUX modules. A AOUX module would just replace a DOUX module?

#4: Would i need to write my own code for this?

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You could watch MIDI messages and guess at the level of the resulting audio output.

Including CC#7 and velocity information could make it more accurate, but in the end, you'll have a guess. You cannot predict the ADSR envelope of the audio by watching the MIDI stream, so you won't really be watching the audio level, just an estimation based on the MIDI events that triggered it.

There are easy, single-chip VU meter drivers that have audio inputs, and a group of LEDs driven directly from the chip. These require actually connecting to the audio signal.

Another method that I considered (but never built, yet), is a simple sample/hold circuit connected to an AIN, which would allow you to read the audio level directly into a core. Then you could output a MIDI stream to a remote meter or display. As I mentioned in another thread, this would also allow a software-driven AGC if you also have a MIDI controlled mixer. Software filtering of the meter stream would also allow user-configurable VU damping control.(fast, medium or "peak" response meters)

In any case, if you want to see the actual sound level, you'll need to monitor the actual audio signal.. Unless someone knows a better way..??

Have Fun,

LyleHaze

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Traktor (software i'll be using) sends out a midi output with a certain velocity

if you are sure of that it is rather easy to code :

l

evel  = velocity


if level > 64 

then Led0 on

 Led1 On 

 Led2 On


if level >80

then Led0 on

 Led1 On 

 Led2 On

 Led3 On

etc ..

search in BLM with RGB Led there is a sort of this code

if the velocity is under 64, there is only one led

if 64<velocity<80 there is 2 leds

is >80 there is 3 led

i've coded in 8 colors (so 8 leds) velocity scale (0-127)

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Thanks for the response guys.

I think i got it now. I've been thinking of a way to convert a midi signal to a Volt output to make the VU.

But i guess you can just simply use the LEDS on your DOUX and code them to go on on Midi Note X with velocity X?

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you can just simply use the LEDS on your DOUX and code them to go on on Midi Note X with velocity X?
YES

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