Sensthethesia

Here is a demonstration of what square waves look like.

This is a stereo square wave(phase difference 90 degrees). It should be a square on the X-Y plotter.

Here is a chord of square waves. Notice the “constructive interference” as more notes are brought in. One note plots 1^2=1 squares, Two notes plots 2^2=4 squares, Three notes plots 3^2=9 squares, and so on. So it’s N(#notes) squared! Playing certain chords will trace only certain parts of the squares depending on their harmony.

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Here is the song I was talking about in the previous entry.

It’s pretty simple. It’s just chords with 3 sine waves and a 4th quiet wave.

It’s best viewed with default settings with scale set to 3 on the channel one and two of the X-Y plotter.

I’ll load an example of square waves and the “N^2.”

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Here are some sites for reference.:How to tune musical notes.

• Frequency/Wavelengths–>Musical Notes” http://www.phy.mtu.edu/~suits/notefreqs.html

• This explains the ratios of

Chords:http://www.phy.mtu.edu/~suits/chords.html

Scales:http://www.phy.mtu.edu/~suits/scales.html

• This one has some of the math involved: http://www.techlib.com/reference/musical_note_frequencies.htm

• This one you enter frequency and gives you the Note+cents: http://www.phys.unsw.edu.au/music/note/

• Can’t go wrong with Wikipedia: http://en.wikipedia.org/wiki/Note

I thought I would post this stuff for future reference. Could come in handy when tuning electrical components in Hz when you want musical alphanumeric tones and chords.

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Ok, I have been playing with this thing all day (The Oscilloscope). I hear that this application might only work on XP. Sorry about that. That happens to be what I am using. If you find one thats cross-OS or even just for other OS’s tell me and I’ll post it. Anyway, let me tell you how to set this up.

Once you get this installed. Click the scope icon in the Start/All Programs/Scope/Scope. A screen will come up with 5 tabs.

The first tab is the “Oscilloscope.” This graphs the input signals (channel 1 & 2 –>which we will make left and right speaker) Amplitude (or loudness , voltage) up and down versus time left to right. This will make the familiar pictures like window media player make in many different styles (wrapped in circles etc). You can analyze wave shapes and phase. Wave forms are the shape of a signal for example a sine wave is the smooth wave like waves in water or a square wave which look like boxes (you can see some when you start using tab 4 signal generator). Phase is the relationship between the left(green) and the red(right) signal. When you have two signals that are exactly the same and are one on top of the other, they are said to be “in phase.” This is how monaural(mono) sound works. This sound will sound like it’s in front of you and because both signals are doing the same thing at the same time, you would only need one signal to make the same sound . Now, imagine shifting one signal to the left or the right. The farther they shift to the left and the right is measured and this is called going “out of phase.” When the sound is 90 degrees (trigonometry is involved, sines and cosines etc), this is how stereo sound works and this is how they make music sound closer or in your head.

Ok, the next tab is a little less intuitive but is how some laser shows work. The “X-Y” tab. This is where the magic happens. Lets skip it for now.

The the next tab is the “Frequency Analysis” tab. This has a a graph of what frequencies are present in a signals. Relative amplitude versus the frequencies. Say you have a middle A playing (440hz). There would would be a upward spike on the graph at 440. You can check this later when you master the next tab. What you will want from this tab is the filter. There is a gray box in the middle of this tab labeled “Frequency Filter in Separate Window.” You might want to check that and put the little window to the side for later or leave it alone and goto this tab to when you want to use it.

Then next tab is the “Signalgenerator” tab. This allows you to make controlled signals. One is labeled Channel 1(left) and one Channel 2(right). This also allows you to change the wave form, frequency (pitch), amplitude(loudness), and phase (as explained earlier. Use this screen to make signals to test your other tabs and familiarize with the application and the lingo.

The Next tab the “Extras” tab. There is a recorder on the bottom. I haven’t used it yet. The top half is the options for your input and output. Make sure that you click on “input” box and that the “Stereo Mix” channel is selected as the input( If you don’t see stereo mix, goto the options/properties in little “recording control” window and put a check next to stereo mix and click “ok” (Note: You are now “recording everything you hear.” by putting a check in “select under the stereo mix volume bar). Also, you may not want the volume on that turned up very high or it will peak out. That is where a signal is so large there is no more energy to express it. It’s like a sine wave thats so big that it bumps the top of your screen. Now the tops and bottom are fattened and it’s more like a square wave (this is a distortion). Information is lost because it doesn’t fit. You might experience this audibly when you crank your stereo too loud and the music sounds fuzzed and different. So don’t do it. Make sure your graphs don’t have flattened edges on the graph when they shouldn’t or sound over driven. It takes a little experience to know when it’s happening some times.

Ok, so everything is set up. Lets go back to the X-Y tab. This graphs each channel on a different axis. When the left channel goes up and down on the first tab, the point on the X-Y graph will go left and right. Channel 2 will make the point go up and down. Thats how it works.

Ok, so here are some scenarios.

Mono sound: You have 2 waves exactly the same on top of each other. This will make the point go up and right at the same time and the down and left and the same time. This will make a diagonal line on the X-Y graph. Try this on the signal generator (I would start with sine waves 440hz(middle A)). Turn one channel on. Go look at the vertical or horizontal line. Turn on just the other and the other axis be traced. Then turn on both with the same amplitude and make sure both are on 0 phase. This will make the diagonal line.

Stereo sound:Use the diagonal line example above. Start moving the phase of one channel. The first tab you should see one graph slow shift away from the other. The X-Y should slowly form into a circle (Circle should be a 90). If your circle has a weird line in it or it’s square (when you are on sine waves) then you are overdriving something. For the weird line try turning down the amplitude of the signal generators (but make sure they are the same!! or you’ll get an oval). For the square you might need to turn down the stereo mix in the extras tab->input.

Cool, you are are making Lissajous Curves.

I have made some songs just for the X-Y graph. When I figure out how to post them, then you can download them. Try making your own music if you know how or listen to your favorite songs. Make sure they are in stereo. Mono songs will just make diagonals (unless you know how to make stereo out of them). Not sure if it’s stereo? Play it and look at the diagonal. You are now analyzing signals!

**I’ll add pictures of what I am talking about later.**

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Well well well,

It’s about time for another BLOG entry. Otherwise, I’ll never get in the habit of using it.

Lots of cool ideas this week. WOW! it’s going to be hard to catalog all this. I’ll just add them as they come up, get used, someone asks for it, etc.

Heres something interactive for the reader. I discovered a nifty sound-card oscilloscope. Allows you to graph signals. Probably more interesting : MUSIC! What ever sounds your computer makes, you can graph it in a number of ways. Us electrical engineers use them to analyze electric/electromagnetic signals, but you have probably experienced some of the artistic uses on windows media player or any other of those widely used and resource hogging programs out there.

So, Tommy, where do I get one of these ossilly-scopes?

Well, glad you asked! I posted it on the TASD mailer-list (I think) but in cae you missed it here is the link. AGAIN! WHOA!

http://www.zeitnitz.de/Christian/Scope/Scope_en.html

Get this and you will have your own personal “Sensthethesia.”

I have been playing around with it and have gotten some pretty neat stuff with it. It hasn’t bothered my input like Tom McGuire said it might, just a little fire out of the microphone port… I suggest you try it! (It’s free)

I’ll post some tutorials on how it works and how to tune it. I might even make some songs for it for you to watch. Reciprocally, you should be able to find and make songs for me as well.

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