Thread: No Cost Spectrum Analysis

just down loaded the program from Audacity: Windows
and having a look
the one i was using was "tone " a tone generator that comes with "circfft" a note plotter in a circle that shows the harmonics from Tolvan , it would be good to see different insruments pinging a single note ( screen Shot from pressing "Print screen" button and clipboarding it to your image editor

Hi Wayne,

Thanks for the tip on the software, but doesn't the preamp change the frequency spectrum? Wouldn't the picups change the frequency spectrum? Wouldn't you need to mic the guitar accoustically to get a true frequency spectrum of the guitar timbre?

Cheers

Peter

Both Audacity and the older Felt tip Pen will take the output directlly into the 'puter from an electric guitar without any pre-amp "colouring"

Just an addition, a bloke that built a few for me, used to use a stethoscope directly on the wood with a transducer up the pipe to convert the signal.
He reckoned after a lot of testing that he could negate any "colouring" introduced from the transducer, but then again that's all a bit subjective.
The main use of the Stethoscope in my case was to get the ultimate amount of sustain on the 5th string....just because of how and what I played.
Then again, if he shifted the Steth (can't be buggered typing that again) the results would subtly change.

Exactly, everything changes it including the audio libraraies, but it can be useful as self reference. Yes, it is subjective because someone at some point needs to use their ears and there are other factors. What you hear on a recording is not the same thing that is heard in a room with a given setup. It can be used as a reference for one person using the same setup in the same environment and so on, but that's about it. Everyone's setup is different, so comparing samples from different builders audio files can be meaningless.

Gday Guy's,

Another Sermon haha!

Yes, i agree with a lot of things that have been mentioned.
(That's Unusal Hey Guy's haha)

watson
Yes exactly, looking for specific Frequencies & or Resonance to suit what you needed, that's the key to it all.

Peter,

Using a preamp is not an issue, it will only amplify your original signal, it will give you a set standard measurements from which all others can be judged.

If your having trouble i may be able to help you with that as i also do electronics & make preamps, custom effects circuits & wind my own pickups etc.
Actually i have been looking into winding some custom pickups for people as well.

You will be able to use yours for testing i am sure as it will be the same each time you test just use the exact settings on the amp each time.

The final Timbre of the instrument is actually what your testing with the preamp & the program, overtones are the natural timbre of the instrument & overtones are frequencies so reading frequencies is all you require.

mkat said:

"It can be used as a reference for one person using the same setup in the same environment and so on."

Exactly!

This is what you want, to test you have to have the exact same setup each time you test something with no exceptions or your results will be meaningless.
As watson mentioned also even a small difference in the placement of transducers etc will make a difference to your results, so to be able to plug into the output jack is a huge advantage & simplifies things.
The Instrument doesn't need to have the finish applied to test things out & there best tested in the actual playing position.

Repeatability is accuracy so this is a must, it wouldn't matter if you sat a glass of water on the body for instance & played notes to watch how the different frequencies affect the top of the water, if you had it repeatable & could read it of course.

What your testing for is "DIfferences" in what your doing & hearing so the setup doesn't really matter, with the use of programs like Audacity etc & a couple of cheap items you can get excellent results without the cost of expensive equipment.
Actually it makes me sick when i think how much money i have spent on good test equipment over the years & as times progress it's all available cheaply or for nothing. Nothing like technical advances.

Although i wouldn't like to delve into my setup here there is a very good way to get some great meaningful results.

If i were you i would have one set of humbuckers & one set of single coil pickups as well (if you use both) & a set standard control panel for each with all the tone controls etc totally finished & locked off so they can't move--for what your hearing each time.
Use these everytime you test something & make certain the pickup heights etc are the same each time. You really only need one pickup to test from but having the others & everything else in it's correct place can be advantageous rather than have empty cavities where pickups etc should be or unconnected wiring etc.

Once you have a good Spectrum Analysis baseline to work from then each & every test after that can be compared with the exact same components. The main thing as mentioned is repeatability so test that first up to make sure your test setup is accurate. Your never going to beat Accuracy.

Now your going to laugh at this but i have found that interference from the mains & electrical equipment can be a real problem & bugger up the best of proceedures.

I have a small room that i go into to test things with all the equipment outside of this & this room is lined, top, bottom & sides with fine bird wire, the wire netting with small squares about 1/2" or 12mm in size & then lined with Aluminium Foil, painted with a spray can so it doesn't blind you. You can just use the foil but i tried the Bird wire first & then added the foil later.
This creates a Farraday shield of sorts & i don't get any electrical interference from outside influences. She works great.

mkat was exactly right about recording things, you also have to use your ear & your own perception of what your hearing.
It won't take long before you can look at the Frequency Spectrum & have an idea of what your seeing & what you'll hear as a result.

For instance, if we look at just say the Low, Mid or High range frequencies on the Spectrum Analysis of your base line test which you will also have heard & will get an understanding of the sound associated with this.
Now we do another test with another prototype or whatever & we can see there are more or less low range frequencies for instance or of less or greater Amplitude than before you will hear this & you will get to know what your after & what you don't like.

By all means use your own idea's for testing things..

Just remember it's not only just Frequencies your looking for but the Amplitude of those frequencies as well, some frequencies i find hard on the ears so to have those completely gone or of a much lower amplitude is very helpful. On the other hand you want the pleasant sounding frequencies to be of a higher amplitude.

My thought's only, there are many ways to skin a cat as they say.

Hope this may help.

WayneW
Linguist Guitars

My god you can talk.

Gday Bob,

Hahaha, no Bob---Dribble

You can show somebody something in two seconds, now try & explain it?

I'll keep this short, watch out for next time though
I'll have withdrawl symptoms by then!

WayneW
Linguist Guitars