Tech: The visual oscillator in your own home

Subject: Tech: The visual oscillator in your own home
From: Slag
Date: 08 Sep 10 - 10:51 PM

I was sitting on the couch, noodling away and my line of sight was looking through the strings at the tube. The G string sounded a little off so I used the standard method of tuning when I happened to notice that the strobe of the TV revealed the oscillations of the strings quite well. Hmmm, I thought. Sure enough I can visually tune my guitar by getting the string oscillations to match frequency while still using the standard method of tuning the strings to match the previously tuned string. I don't know if the A string is at 440 but the guitar is tuned to itself perfectly!

Subject: RE: Tech: The visual oscillator in your own home
From: Amos
Date: 09 Sep 10 - 12:22 AM

Nice to find you weren't selling love aids, Sllag!

Subject: RE: Tech: The visual oscillator in your own home
From: pavane
Date: 09 Sep 10 - 03:11 AM

Of course, you don't say where you are. UK and USA have quite different TV scan frequencies.

Subject: RE: Tech: The visual oscillator in your own home
From: The Fooles Troupe
Date: 09 Sep 10 - 03:30 AM

If both strings are being tuned to the same frequency (ie to each other, so the absolute frequency matters not), I don't see how a differing strobe frequency due to the different TV scan frequencies would matter. The two strings would look the same.

Subject: RE: Tech: The visual oscillator in your own home
From: pavane
Date: 09 Sep 10 - 05:20 AM

True, I suppose

Subject: RE: Tech: The visual oscillator in your own home
From: Slag
Date: 09 Sep 10 - 07:26 AM

Exactly. I have an old RadioShack xenon strobe I might dig it out and see it I can get the same effect with it. The strobe is adjustable. Stay tuned kiddies, for further developemnts!

Subject: RE: Tech: The visual oscillator in your own home
From: GUEST,leeneia
Date: 09 Sep 10 - 09:22 AM

Hello, Slag. Would you please explain further how you were holding your guitar (it was a guitar?) so that you could see a TV at the same time?

Subject: RE: Tech: The visual oscillator in your own home
From: Slag
Date: 09 Sep 10 - 05:13 PM

Well, I was slouched down on my couch with my legs crossed and the guitar in my lap. The fret board was a low horizon with the tube as a setting sun, you might say; all background. Since I was just lazing about, I didn't bother to raise up to re-tune the string but when I plucked it I could see the ocsillations rise and fall- a phenomenon I've seen many times before, I might add, but I never considered it as useful in any way. When I plucked the second string I could see that two scillations did not match in amplitude or frequency. That is what got me to thinking in terms of the TV acting as a type of oscilloscope. As I tuned it to ear, I noticed the visual resonnance also aligned! Viola! (No, it wasn't a violin, PLEASE!). Er? Eureka!

Now as to the xenon strobe: Forget it. At the fastest setting it is probably too slow. It is way too bright to look directly in on and too bright even set to a side. Actination is also a big problem (the persistence of image). The xenon flashes are so short duration that it freezes the motion of the strings rather than allowing you to see the sine waves.

Back to the TV, what is really cool is that when you pluck a single string you can see the dominance of the initial note but as it dies down you can watch the overtone series develop and then subside also.

Subject: RE: Tech: The visual oscillator in your own home
From: The Sandman
Date: 09 Sep 10 - 05:20 PM

sounds more interesting than most tv

Subject: RE: Tech: The visual oscillator in your own home
From: GUEST,leeneia
Date: 10 Sep 10 - 12:16 PM

Thanks for the explanation, Slag. I tried it using my computer screen, and I can see the movement. But it goes too fast for me to determine anything. Your eyes must be better than mine.

Schweik - too true.

Subject: RE: Tech: The visual oscillator in your own home
From: Paul Burke
Date: 10 Sep 10 - 01:44 PM

You could make one quite easily with a crystal- controlled oscillator and a high- powered LED. Should cost but a few pounds/ dollars in parts. Probably easier to use in a noisy room than a microphone based tuna.

Subject: RE: Tech: The visual oscillator in your own home
From: GUEST,leeneia
Date: 10 Sep 10 - 05:48 PM

Oh, Paul! Why would anybody baste a tuna with a microphone?

Subject: RE: Tech: The visual oscillator in your own home
From: Paul Burke
Date: 10 Sep 10 - 06:36 PM

Better than a megaphone?

Subject: RE: Tech: The visual oscillator in your own home
From: Slag
Date: 11 Sep 10 - 01:03 AM

First tuna, second tuna, bass. And they sang just for the halibut.