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Author Topic: instrument overtone tuning analysis  (Read 627 times)

Dan Richardson

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instrument overtone tuning analysis
« on: February 06, 2014, 11:04:07 pm »

Acquaintance is looking for software that will do a spectrum analysis, but identify the major peaks, and hopefully quantify the relationships between them. He's an instrument builder, and wants to be able to see the effects of alterations in progress. SMAART et al will give him a peak at a time, but he's looking at doing hundreds of measurements, so he's hoping for something that will specify, say, the 12 highest peaks and spit them out to a spreadsheet or whatever. Anybody here run into anything like that?
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John Roberts {JR}

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Re: instrument overtone tuning analysis
« Reply #1 on: February 06, 2014, 11:53:53 pm »

It seems a basic FFT spectrum analyzer will give him a usable result. May need a computer with a sound card.

JR

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Dan Richardson

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Re: instrument overtone tuning analysis
« Reply #2 on: February 07, 2014, 09:42:58 am »

It seems a basic FFT spectrum analyzer will give him a usable result. May need a computer with a sound card.

JR

He's looking for something to give him an automated readout of multiple peak frequencies.
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Art Welter

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Re: instrument overtone tuning analysis
« Reply #3 on: February 07, 2014, 02:13:52 pm »

He's looking for something to give him an automated readout of multiple peak frequencies.
The Smaart Spectrograph gives a visual readout of the peak frequencies as well as the spectral decay.
The exact frequencies can be picked out with the cross hair, but the "character" of the harmonics is easy to see visually.

I just sang, whistled and played some notes on an Ovation acoustic guitar (with ancient strings)  using the built in computer mic.
The whistle has very little upper or sub harmonics.
The voice ( "ahhh" notes) has more harmonics (and not as defined pitch, I was sloppy) which are primarily 2nd, 3thd and 4th order, the fundamental note being the strongest.

The guitar fundamentals are not as loud as the harmonics, and the subharmonic on the high E is louder than the fundamental. The upper harmonics on a sustained note initially are similar in harmonic content, but the way they die out is different.
The difference in harmonic arrangement as well as their sustain are the signature of every instrument.

A readout of only the peak frequencies would not give as much of a clue to the harmonic character as a spectrograph, as it would only give a reference at one point in time.

Art
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Chris Tsanjoures

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Re: instrument overtone tuning analysis
« Reply #4 on: February 07, 2014, 02:48:21 pm »

Acquaintance is looking for software that will do a spectrum analysis, but identify the major peaks, and hopefully quantify the relationships between them. He's an instrument builder, and wants to be able to see the effects of alterations in progress. SMAART et al will give him a peak at a time, but he's looking at doing hundreds of measurements, so he's hoping for something that will specify, say, the 12 highest peaks and spit them out to a spreadsheet or whatever. Anybody here run into anything like that?

an analyzer such as Smaart, especially the spectrograph, will give you insight as to what the harmonic structure of the input signal is. However - as my high school physics teacher would always say about the Texas Instruments TI83 - it's just a stupid machine. It will take you , the operator to interpret the results. You can for example, save a trace and dump it into a spread sheet, or compare multiple different traces (look out for 'trace compare' feature coming soon). AFAIK, people that do these types of measurements have either invented their own process or take the time to do the investigation.
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Dan Richardson

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Re: instrument overtone tuning analysis
« Reply #5 on: February 07, 2014, 04:13:26 pm »

it's just a stupid machine.

Yep. I think we've come up with a more useful approach. He doesn't actually care what the specific numbers are, he just wants to be able to see the variance. With any 2 channel spectrum analyzer, he should be able to put his instrument source in one side, and a software synth on the other. Build the overtone series he wants on the synth, alter parameters in the instrument, and variance should be quite evident. Might even work to use a Hammond emulator, since the drawbars are essentially partials and overtones.
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