Lunetta visualizer, old tv

Kabzoer · Joined: Feb 07, 2011 Posts: 82 Location: Belgium

The general idea is to get yourself an old tv, put the lunetta output to the audio input.
Great, now the amplifier in the tv will play the sound, but now you put the lunetta output not only to the audio, but to the VIDEO input!
Some video footage:

http://www.youtube.com/watch?v=ymzA0rB-6BY

Now, the only thing I'm getting from this setup are some stripes, but if you try ultrasonic oscillators, you can get some interesting patterns.
Any idea to make i a bit more interesting?

stolenfat · Posted: Wed Oct 26, 2011 6:27 pm Post subject:

i wish you could do this with newer tvs. any ideas on how to get newer stuff to take audio outputs into there video ports?

Cynosure · Posted: Wed Oct 26, 2011 7:13 pm Post subject:

I have no clue what is involved, but I know that some people have converted old crt screens into an oscilliscope.

kaputtpanzer · Posted: Thu Oct 27, 2011 1:09 am Post subject:

kaputtpanzer · Posted: Thu Oct 27, 2011 1:13 am Post subject:

ooops I forgot there is no scart or euroav in canada and the us? Isn't it?

tjookum · Posted: Thu Oct 27, 2011 3:20 am Post subject:

I really liked the video, well done.

There has been a previous discussion on adding visuals to lunetta's on EM:
http://electro-music.com/forum/post-303930.html#303930

I've tried several times to add a sync or even a colour signal but the nature of the needed signal makes it really impractical for lunetta. High freq. and high accuracy are very difficult to achieve but you can get some interesting results none the less.

Kabzoer · Joined: Feb 07, 2011 Posts: 82 Location: Belgium

I connected them to an rca input, it looks like this:
http://wintal.com.au/info/guides/images/02_RCA_TV.jpg

A fun thing is that my tv syncs to the signal automatically, so if you have a stable clock source, it locks it and the lines on the screen will stand still.
If you want to make an oscilloscope from it you'll propably need to open the tv and disconnect the coils from their original source. I tried it and my old CRT monitor imploded...

kaputtpanzer · Posted: Thu Oct 27, 2011 2:43 pm Post subject:

look ma' it's sound controlled http://www.youtube.com/watch?feature=player_embedded&v=u8tQKznRV7Y#!

kaputtpanzer · Posted: Fri Oct 28, 2011 7:34 am Post subject:

RingMad · Posted: Fri Oct 28, 2011 4:34 pm Post subject:

Just a few things I've observed in my experiments involving visualizing audio....

1. Audio signal into the Composite video in jack (RCA) of the TV. You will get white horizontal lines, related to frequency. e.g. higher pitches are finer lines, lower pitches are wider lines. Things get more complicated the more frequencies there are in the input signal. Super low (e.g. < 1 Hz) can do some interesting stuff, although you might think your TV will explode. Sometimes you can sortof hear something straining inside. Maybe you want to avoid using your new TV for such things. Note that I've only done this on my old CRT TV, and I'm not sure if it works on an LCD or LED.
There was a CD on raster-noton that was designed to be played on a TV in this way. I never heard/saw it, but it's this: http://www.discogs.com/Noto-Telefunken/release/45661 .

2. Turn an old CRT TV into an "oscilloscope". Well, a bad oscilloscope. Sine waves are ok, but I could never get a proper square wave with. But it's fun to look at anyway. You can usurp just one steering coil and get a more classic scope-type image, although vertically instead of horizontally, or you can feed the audio to both coils and get Lissajous-type things. Be sure to read about the dangers of opening up TVs and how to discharge the CRT. This page tells you how to convert the TV: http://www.zyra.org.uk/oscope.htm , and there are some youtube videos around too.
Usually you need to amplify the signal a lot. I did two Lunetta improvs showing the signal feeding a DIY "oscilloscope"... here's one : http://www.youtube.com/watch?v=9JzhqojiARU . I fed the Lunetta output into a mixer, the main outs going to my speakers, and the alt outs going to an amplifier which drove the scope.

3. A general problem in working with video, like say, you think it might be cool to run a video signal through your delay pedal. Well, it doesn't work like that, because you lose the sync signal, or it gets filtered out or too mangled for the TV to respond anything but the classic wavy lines when the vertical hold is off.
You can modulate audio in video by mixing them, i.e. mix the audio signal with some video signal, so that you have sync, but it's basically lines modulating the video, an IMHO, not too interesting. It's been many years since I tried that stuff, but try sound < 10 Hz and well over 20KHz. A friend had lent me a function generator that could go up to about 150 KHz, and I got some crazy patterns mixing that with other audio. I never got my hands on one that could go up to 5 or 10MHz... I always wanted to try that, although maybe that would blow up the TV. I figure the color sync signal is 3.57 MHz (NTSC), so it should at least be able to take that.