Thread: Harmonic Testing Of Guitars

Gday Guys,

I promised before to explain how to set things up cheaply to test guitars for their harmonic content.

Ok first of all their are many guitars made now days that do not fit the bill as far as harmonics go. I have stated before that the use of old growth timber is the way to go & I shall continue with that as we proceed into this.

I would like to share with you a very simple test of a new Acoustic guitar manufacturer not named.

I went & purchased this guitar at a music shop for this test & as usual it sounded bloody terrible, I set a few things up & had a look at the harmonic spectrum, well what their was of a harmonic spectrum.
How people can sell this crap with their name on it is beyond me.

Anyway after looking at the complete lack of harmonics it occured to me the whole spectrum was suffering.
I spent a day fixing the problems or where I thought the problems were & it has improved the spectrum & the guitar very nicely although it is still not to my complete liking but that is due to the timber used for this particular guitar.

I have attached two pictures of the spectrum analysis, before & after fixing it.
You will note in the before picture of the analysis that the low frequencies--the bass are very poor & that the entire spectrum is patchy not to mention the higher frequencies--overtones that are lacking.
In the After picture of the analysis you will see that the entire spectrum is now full & complete all be it like mentioned still not anywhere near correct but still far better than before.

How does it sound?

I recorded the before & after fixing the guitar sound by just playing a single chord, I will attach the sound clip.
The first chord you will hear is the before & as sold sound & the second chord you will hear is after me fixing it to a point.
You be the judge.

Now don't get me wrong here, this guitar is still far from right & used as a test dummy only to show certain aspects of what we need to achieve to put our name on things.
Their are many existing problems with this guitar & the spectrum tells it all.

This is one of the most important aspects of guitar building & without it you don't know where you are.

If their is some interest I will take the time to explain proceedures & methods for making & testing some nice guitars to be proud of.
Also I can share some really nice harmonic spectrums to work for--truly great sounding instruments.

I'm a put your money where your mouth is type & I'm prepared to do that, it's important to me that people work towards building nice instruments before the trade is gone completely.
Todays trade seems to be about the dollar & not sound quality, this is a mistake as people will pay for quality.
Some of the instruments today are a far cry from what they should be.
It would be a shame if people think this is how guitars should sound.

WayneW