What Tools Would I Need to Capture Measurable and Quantifiable Metrics Of Different Types Of Resonator Guitar Coverplates

[RAMBLIN_RAWB]

Hey everyone, hope you are well! Could you use some direction with tools to gain measurable, tangible results and test frequencies emitted from different types of Reso Guitar Coverplates. Does anyone have any open-source programs, perhaps Audacity? That I can use to measure and test said frequencies coming out of different types of Resonator Guitar Coverplates? Any direction or advice on how best to do this would be greatly appreciated!

I know I need to devise multiple controls regarding the guitar ie. mechanical strumming device to cancel out human variables and create a control with sound input.

Located in western North Carolina just in case there is someone close to me

Kindest!

 

[EERecordist]

Hello, welcome to ASR!

One approach is to get the Room EQ Wizard software, REW, discussed often on ASR, and a calibrated USB measurement microphone like the miniDSP UMIC. The software is free and the microphone about $100.

If you play one string you will see the harmonics and amplitude with REW in peak trace mode.

Without the resonator, a single note will produce a spectrum of harmonics. Then try each resonator in turn and you can compare the harmonics and their amplitude. You could also compare low notes and high notes.

If it works out, it would be fun to see the results.

 

[MAB]

Yes to using REW and a measurement microphone. UMIK-1 should work very well. Fancier mics are available, but I really don't think they will make a big difference (I use an old Nakamichi omni with a simple mic interface at times with great success). Here is an RTA capture of a clarinet playing 440Hz with different embouchure:

We were discussing timbre, and I thought capturing the different spectra with different embouchure would help the conversation!

 

[antcollinet]

Hey everyone, hope you are well! Could you use some direction with tools to gain measurable, tangible results and test frequencies emitted from different types of Reso Guitar Coverplates. Does anyone have any open-source programs, perhaps Audacity? That I can use to measure and test said frequencies coming out of different types of Resonator Guitar Coverplates? Any direction or advice on how best to do this would be greatly appreciated!

I know I need to devise multiple controls regarding the guitar ie. mechanical strumming device to cancel out human variables and create a control with sound input.

Located in western North Carolina just in case there is someone close to me

Kindest!

This does sound like it is going to be very difficult to get distinguishable results.

I"d guess each 'Strum" will have a mass of frequencies and harmonics. I suspect it will be very difficult to identify/analyse the differences between cover-plates, as distinct from "strum to strum" variation (even if mechanised).

 

[Barrelhouse Solly]

This is an interesting project. It sounds difficult to to set up. I have a couple of resos and have never considered cover plates. I assume you've played with cones. I'm wondering if the ideal cover plate should be acoustically transparent or shape the sound.

 

[RAMBLIN_RAWB]

Hello, welcome to ASR!

One approach is to get the Room EQ Wizard software, REW, discussed often on ASR, and a calibrated USB measurement microphone like the miniDSP UMIC. The software is free and the microphone about $100.

If you play one string you will see the harmonics and amplitude with REW in peak trace mode.

Without the resonator, a single note will produce a spectrum of harmonics. Then try each resonator in turn and you can compare the harmonics and their amplitude. You could also compare low notes and high notes.

If it works out, it would be fun to see the results.

Thank you for the warm welcome! Yes, this is what I am aiming for and free software sounds great to me! Appreciate all of this!

 

[RAMBLIN_RAWB]

Yes to using REW and a measurement microphone. UMIK-1 should work very well. Fancier mics are available, but I really don't think they will make a big difference (I use an old Nakamichi omni with a simple mic interface at times with great success). Here is an RTA capture of a clarinet playing 440Hz with different embouchure:
View attachment 432696
We were discussing timbre, and I thought capturing the different spectra with different embouchure would help the conversation!

yes!! perfect! I can't wait to check this out more in depth!

 

[RAMBLIN_RAWB]

This does sound like it is going to be very difficult to get distinguishable results.

I"d guess each 'Strum" will have a mass of frequencies and harmonics. I suspect it will be very difficult to identify/analyse the differences between cover-plates, as distinct from "strum to strum" variation (even if mechanised).

Thanks for the response! I'm curious what difficulties you foresee? If I'm understanding correctly, is one difficulty you see in the strumming?

 

[617]

yes!! perfect! I can't wait to check this out more in depth!

Play the purest, most simple tone you can play on the instrument when comparing. A 12th fret harmonic on the g string would be what my choixe. This will help you focus on the harmonics created by the resonator rather than the string itself. I can't remember if resonators sound less resonatory at low volumes, I feel like something happens when you play them harder, but this should work.

If you use a mic, you'll need to use it in a quiet room. If the mic is too close, it will be capturing the particular harmonic radiation at one point in space rather than the average radiation we hear. Especially at high frequencies, vibrating diaphragms have chaotic spatial radiation characteristics, so measuring up close may not give you an apples to apples comparison. Same deal with guitar speakers, at high frequencies they break up into multiple radiating regions which change shape at different frequencies.

You could try a piezo pickup but again they will give different measurements depending on where you mount them.

 

[RAMBLIN_RAWB]

This is an interesting project. It sounds difficult to to set up. I have a couple of resos and have never considered cover plates. I assume you've played with cones. I'm wondering if the ideal cover plate should be acoustically transparent or shape the sound.

Thanks for reaching out! Im looking forward to the challenge tbh! The ideal coverplate should work in tandem with all the components of the resonator system itself to create the best balanced sound and projection. Small sound holes stifle, and big dynamic sound holes create an unbalanced, disorganized sound. I feel coverplates are an often overlooked yet integral component and mouthpiece of the resonator. The best way I can extend and demonstrate this exercise is this: cup your hand over your mouth, sustain a note, and open and close your hand slowly using the bottom of your palm as a hinge. Do you hear the difference?

 

[antcollinet]

Thanks for the response! I'm curious what difficulties you foresee? If I'm understanding correctly, is one difficulty you see in the strumming?

look at the clarinet plot above. That is just from a single note playing - but you see all those harmonics.

Youll get a similar result (I guess) plucking just one sting of a guitar. If you strum all 6 there will likely be 6x the number of peaks, and they will all be varying over time as the note decays.

I don't know, but I guess that the difference you will see between resonator plates will be less (or a similar level) to the veriation you will get from one "strum" to the next. It will be difficult to separate the strum differences from the plate differences.

I am speculating a little here, I've never seen the spectrum of a strummed guitar. I may try it later.

 

[Bergante]

Some ideas.

Use a contact transducer and fine iron fillings together with a camera.

https://www.speech.kth.se/music/acviguit4/part7.pdf

 

[RayDunzl]

I"d guess each 'Strum" will have a mass of frequencies and harmonics.

Open strum spectrum of electric guitar

Red is peak value.

Black is "real time" moments after the strum.

 

[RAMBLIN_RAWB]

look at the clarinet plot above. That is just from a single note playing - but you see all those harmonics.

Youll get a similar result (I guess) plucking just one sting of a guitar. If you strum all 6 there will likely be 6x the number of peaks, and they will all be varying over time as the note decays.

I don't know, but I guess that the difference you will see between resonator plates will be less (or a similar level) to the veriation you will get from one "strum" to the next. It will be difficult to separate the strum differences from the plate differences.

I am speculating a little here, I've never seen the spectrum of a strummed guitar. I may try it later.

I am also concerned about the strumming, I was going to try to pluck each string with a control robot haha just have to build it...maybe use a metronome motor

 

[RAMBLIN_RAWB]

Open strum spectrum of electric guitar

Red is peak value.

Black is "real time" moments after the strum.


View attachment 432980

yesssssssss thank you! So this seems plausible and legible with a strum! I still would like to test out each string to see what resonator coverplates are more conducive to high end low end spectrums

 

[RAMBLIN_RAWB]

look at the clarinet plot above. That is just from a single note playing - but you see all those harmonics.

Youll get a similar result (I guess) plucking just one sting of a guitar. If you strum all 6 there will likely be 6x the number of peaks, and they will all be varying over time as the note decays.

I don't know, but I guess that the difference you will see between resonator plates will be less (or a similar level) to the veriation you will get from one "strum" to the next. It will be difficult to separate the strum differences from the plate differences.

I am speculating a little here, I've never seen the spectrum of a strummed guitar. I may try it later.

I also would like to test out each string to see what plates are more conducive to high end low end spectrums of different coverplates

Play the purest, most simple tone you can play on the instrument when comparing. A 12th fret harmonic on the g string would be what my choixe. This will help you focus on the harmonics created by the resonator rather than the string itself. I can't remember if resonators sound less resonatory at low volumes, I feel like something happens when you play them harder, but this should work.

If you use a mic, you'll need to use it in a quiet room. If the mic is too close, it will be capturing the particular harmonic radiation at one point in space rather than the average radiation we hear. Especially at high frequencies, vibrating diaphragms have chaotic spatial radiation characteristics, so measuring up close may not give you an apples to apples comparison. Same deal with guitar speakers, at high frequencies they break up into multiple radiating regions which change shape at different frequencies.

You could try a piezo pickup but again they will give different measurements depending on where you mount them.

love the harmonic idea...i do still think that human hand variables, even with harmonics, would still impact the test...perhaps I am overthinking the human hand variable haha

 

[RAMBLIN_RAWB]

Some ideas.

Use a contact transducer and fine iron fillings together with a camera.

https://www.speech.kth.se/music/acviguit4/part7.pdf

thanks for this!!

 

[Multicore]

Mute the strings and tap the bridge with a suitable mallet, e.g. a wine cork on a fondue fork. Average ten taps.

REW and a calibrated measurement mic will give you correct absolute members but you can get started with a spectrum analyzer app on your phone. It should reveal the main differences between different resonator builds. I use an Android app called Spectroid.

Show us what you find. It should be fun.

 

[RayDunzl]

I might try placing the guitar very close to a speaker, maybe right up against the back, play a slow sine tone sweep, and see where the rattles appear.

The frequency range of an acoustic guitar’s fundamentals—its primary note pitches without harmonics—spans roughly 82 Hz to 1,318 Hz, covering the standard tuning (E2-A2-D3-G3-B3-E4)

 

[antcollinet]

Mute the strings and tap the bridge with a suitable mallet, e.g. a wine cork on a fondue fork. Average ten taps.

REW and a calibrated measurement mic will give you correct absolute members but you can get started with a spectrum analyzer app on your phone. It should reveal the main differences between different resonator builds. I use an Android app called Spectroid.

Show us what you find. It should be fun.

Now that might be interesting - effectively measuring the impulse response of the guitar.

It could even be repeatable if the "mallet" were on a pivot being dropped from a controlled height onto a consistent location on the guitar. (just below the bridge, perhaps)

EDIT - I would be tempted to leave the strings open, since they form a significant part of the resonant structure of the guitar. Or at least try both open and muted.