Sebastian Herrlinger

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since Oct 08, 2008
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Recent posts by Sebastian Herrlinger

Hey there,

I have a M-Audio X-Session Pro USB Midi Controller and now I want to use it to control some parameters in my App. So my question is: How can I do that? Is there a "simple" way to communicate with a Midi Controller?

Thanks for any help!
16 years ago
I would use natives if there is also one for mac, because that's the target system which I will be using. For now I have to figure out how to get my DFT to a FFT... I am on it... Thanks for all your help!
16 years ago
Thanks again very much for your superior help!
I managed to get what I want... in a way. But the CPU is very busy for just having a visual EQ. Is there anything I can do to speed things up with the FFT or make it use less CPU? You wrote something about using log instead of sin() and cos(). How do I do that? Haven't read anything about that in the Articles I have here right now. Sorry again for my bad Math
I did a little Video and uploaded it (Big day, first youtube video =))

http://www.youtube.com/watch?v=MCJNoDE2vsM

There you go... you can see what I have so far. I also know now how I could make it 32 or 64 bands to display. I just let the "FFT Loop" call the custom paint()-Method of my EQ-AWT-Canvas-Object every cycle. Without the recording Tool I get about 60 fps on my 2Ghz/1GB (Single Core, about 7 years).

Another Question that came up was: How do I measure the volume of each frequency spectrum I have? Decibell? All I did for now, was to multiply my doubles with 100 and (int) them to have usable numbers for animation. Is there any kind of normalization I could do?

Sorry to bother you with another bunch of questions...

Thanks very much!!!
16 years ago
Ok, I did it. So what I get now is a curve.


Mhhh... looks nicer, if all the curves are drawn, but the screenshot didn't work. What I did was:



So thats the Waveform of the Signal? A single Signal?
How can I link it to a Form like:


Thank you really much to help me through this. I think I am on the way of understanding, though it is hard. Also I'm german and the english vocabulary confuses me sometimes
[ October 13, 2008: Message edited by: Sebastian Herrlinger ]
16 years ago
I see... I cannot get a running Equalizer Visualisation without getting really into this. So back to learning...
16 years ago
Ok, got it running. With W = 1024 I have a double[] with 512 values. Now what are they expressing? If I want do show them in a graph and take them as y values, what are my y values?
My brain smokes as I am trying to understand the formulas on wikipedia...
16 years ago
Woaa... that is knowledge. Thanks for your help. I will try to get this to work. What still bugs me, is the fact that I don't really know what to do with the set of complex numbers... Are those the frequencies? How do I draw a Graph with them? damn... I sound stupid...
16 years ago
Phew... hard stuff. I can't help myself.

I have those two functions for the Input:


So, what exactly do I have to do with the byte[] I have to link it to an EQ Visualisation that visualizes the Volume of 8 frequency specs?

Sorry, I looked into tutorials and I ordered two books on the subject to really get into it, but I need to get this done somehow.
16 years ago
The Three-Thread-Stack sounds good. But how do I process the byte[]?
Here is what I got:


How can I compute bytes?
Sorry if this sounds stupid...
16 years ago
Sorry, missed that. Corrected.
16 years ago
Hey there,

I unfortunatelly have never done DSP before, but read a lot of Articles on it by now. But I cannot get to the point of really understanding what I can do to solve my Problem, so here is what I got:

I used the Java Sound API to open a TargetDataLine through a Mixer, which is the line-in or mic port of my soundcard. What I get from that is a byte[].

And here is what I want to achieve:

I want an equalizer like App. which shows me the Volume of the single bands like an 8 band EQ. Visualizing the Data later on is not the Problem. But how can I get to the data that gives me for example the volume of the frequencies 30-80hz? I know I have to apply an Fast Fourier Transition to the Input Stream somehow, but how?
I found implementations of FFTs but they all just show itself by a generated Signal, not an input Stream, like I have. So how can I do a FFT on the byte[] Stream I get off my AudioSystem and how can I get the volume like for the example I named above?

Please Help me.

Greetings,

Sebastian
16 years ago