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I'm ready to get set up to collect the spectrographic data necessary to apply Trevor Gore's method of measuring resonant frequencies, but . . . I'm at ground zero.

Trevor includes very helpful information about setting up Visual analyzer on PC to do this in Design, Appendix I 1, page AI-1, but I'd love to know how you're doing it on Mac, from mic to software.

James, it seems that the choice is between using Audacity (which I find a little short on features for what I want to do) or running a Windows emulation program like Parallels, then you have the whole suit of Windows based apps available to you.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

I set up a Macbook Pro in a dual-boot configuration using bootcamp, but I found that the Windows program VA had trouble finding the right Mac ports - it couldn't find the built in microphone. This is undoubtedly a solvable problem, but I haven't gotten around to it so don't have anything useful to say, just a caution of what you'll run into if you go that route. I haven't tried Parallels.

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Jim Kirby
kirby@udel.edu

Thanks for weighing in, guys. Here's what I've come up with so far.

Mics
I found a few attractive mic options. A USB mic like the Apogee MiC or Blue Yeti could be a simple setup that I could also get a lot of use out of for my Skype guitar lessons. The Apogee ONE would let me use my nice tube mic, but the setup with that mic gets old.

Software
I was playing with Audacity. For some reason, the lowest frequency I got in the spectrum analyzer was 1000hz, which makes me wonder if there were setup features I wasn't seeing.

It looks like Visual Analyzer is free, but Parallels is $80.

Trevor what are the shortcomings you find in using Audacity?

Fred

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Fred Tellier
http://www.fetellierguitars.com
Facebook page http://www.facebook.com/pages/FE-Tellier-Guitars/163451547003866

Quote:

"I was playing with Audacity. For some reason, the lowest frequency I got in the spectrum analyzer was 1000hz, which makes me wonder if there were setup features I wasn't seeing."

FWIW, I have used Audacity and the Apogee MiC to plot the tops and backs of several guitars. I'm not experienced in interpreting this data, but the readings appear to show a full range of frequencies. Here is one example:

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George :-)

It's really helpful to see those settings. Thanks, George!

James,
Here's a good thread on the topic:

viewtopic.php?f=10101&t=39117&hilit=audacity

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George :-)

It's a while since I last looked at Audacity, but the things that immediately come to mind are windowing the display and being able to output a frequency sweep and record a response at the same time. Maybe later versions have these features.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au

Was talking to Bryan Galloup at ASIA, and he kinda dismissed Audacity, though I think that's what he started with. Short of using his software suite, which isn't ready yet, he recommended FFT by Studio Six Digital. It's an iPad app that seems to work just fine.

I don't know if there's a version that will work on a Mac. The app is 12.99.

Steve

FWIW, I believe he's quite comfortable using the onboard iPad mic.

Steve

Don't know if it would be necessary for your needs, but I really like Signal Scope Pro by Faber Acoustical for Mac. Costs a bit more than others (I think around $150 now), but was well worth it to me.

I'm sure there's nothing these more elborate programs do that can't be done in freeware, but you're paying for more friendly and intuitive Graphical User Interface they've set up. Seeing as I had no time or ambition to learn how to make a program work like I wanted, I was more than happy to pay for the work others had already done so I could just use it without the long learning curve.

Just food for thought. You might not need anything like this (I use the signal generator and oscilliscope for a number of things as well), but I've been quite happy with it. I even ended up buying the app version for my mobile devices.

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Eschew obfuscation, espouse elucidation.

i have found audacity to be inaccurate. I liked the fft that is on the older version of adobe audition and spectra plus. i have run both on parallels. you do have to figure out the right paths for your mic. i did find the onboard mic on your phone and laptops work ok, but i do like using a mic that has a better frequency response in the low range (20-40hz)

This is very helpful, guys.

Don't tell my wife, but I won a MiC on eBay. The next step is to start exploring the apps. I'll check out Steve's recommendation first, then work up from there. Although I love myself a simple and intuitive interface.

Steve, do you have any recommended settings, or is it ready to go?


Sent from my iPhone using Tapatalk

Another illustrative thread. This is good. I've often wondered how accurate the various spectrum analysis applications really were. Out of curiosity, how does one go about checking?

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George :-)

Run a tone generator and see how the spectrum reader reads it. Even just a tone from an old school guitar tuner or tuning fork. Even tune a guitar to a tuner, then record a note and see what the analyzer says.

James, here are Bryan's settings for the iPad app.

Set windowing to Blackmann
Set overlap to 50%
Set SLP to C-Wtd
Set peak tracking to Large
Change 4096 points to 32768 point

Steve

Thanks, Steve!

The same application will perform with different accuracy on different computers and output accuracy (tone generation) can be different from input accuracy (spectral analysis). Always check calibration. Usually only needs doing once.

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Trevor Gore, Luthier. Australian hand made acoustic guitars, classical guitars; custom guitar design and build; guitar design instruction.

http://www.goreguitars.com.au