Air resonance freq.

Construction and repair of Classical Guitar and related instruments
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Arash Ahmadi
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Air resonance freq.

Post by Arash Ahmadi » Sat Apr 13, 2019 7:09 pm

long time ago, I was reading an article that was explaining what air res. freq. (ARF) would be best for classical guitar. I was just browsing an online classical guitar shop that has recently added the ARF info for some guitars. So with that article in mind, I checked some big names that their CG costs a fortune. Surprisingly, I found D#, A, G# and sometimes F# among them.

So I hope someone can explain that here. I also have another question, how much does the ARF have noticeable effect when the guitar is played? In other words, is that something that the luthier deliberately controls?

Edit: in the article I read, it was explained that F# is the best ARF.
Last edited by Arash Ahmadi on Sun Apr 14, 2019 7:03 am, edited 1 time in total.
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Chris Sobel
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Re: Air resonance freq.

Post by Chris Sobel » Sat Apr 13, 2019 11:55 pm

The air resonance is one of many frequencies on the guitar so it is difficult to just consider it by itself. I’ve noticed a trend in guitar sellers using this information and making a lot of claims about the sound just based on this one element.

As a general idea, older guitars tended to have lower resonances than modern guitars, although many modern guitars are made with air resonances around F# or lower. I feel it gives the guitar a darker, more ‘old world’ sound rather than a brighter and more trebles-forward sound that you might get with air and top resonances around G#.

I’ve made a number of guitars with lower resonances and once you start to go below F it becomes more of a challenge to build in great trebles. I now tend to keep mine from F# up to G# depending on what the client is desiring—it is a variable that I set and can control depending on a number of construction features.
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stratlanta
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Re: Air resonance freq.

Post by stratlanta » Sun Apr 14, 2019 12:25 am

Interesting. I’ve noticed this referenced more often lately as well.
Question though: is it possible that older guitars developed lower resonance simply due to the aging of the guitar as a whole? If so it would suggest that some people are chasing a factor that the original builders never actually considered.
Just a question out of curiosity. I find the building process really interesting.
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Beowulf
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Re: Air resonance freq.

Post by Beowulf » Sun Apr 14, 2019 2:06 am

Listen to "Antigoni Goni meets Hauser" with the discussion and sound for the 1940 Hauser I (from around 5:40 on):
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astro64
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Re: Air resonance freq.

Post by astro64 » Sun Apr 14, 2019 3:04 am

The air resonance is not going to drop much with aging. To obtain a significant change in the frequency you could e.g. thin the top (something that could happen if you sand it down significantly in refinishing the instrument) or add sound ports. The reason the older guitars tend to have lower resonance is because they were built as very light instruments to begin with.

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Arash Ahmadi
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Re: Air resonance freq.

Post by Arash Ahmadi » Sun Apr 14, 2019 7:02 am

Chris Sobel wrote:
Sat Apr 13, 2019 11:55 pm
The air resonance is one of many frequencies on the guitar so it is difficult to just consider it by itself. I’ve noticed a trend in guitar sellers using this information and making a lot of claims about the sound just based on this one element.

As a general idea, older guitars tended to have lower resonances than modern guitars, although many modern guitars are made with air resonances around F# or lower. I feel it gives the guitar a darker, more ‘old world’ sound rather than a brighter and more trebles-forward sound that you might get with air and top resonances around G#.

I’ve made a number of guitars with lower resonances and once you start to go below F it becomes more of a challenge to build in great trebles. I now tend to keep mine from F# up to G# depending on what the client is desiring—it is a variable that I set and can control depending on a number of construction features.
Thanks Chris, yes in that article I read it was explained that F# is the ideal ARF. How can one measure the ARF after the guitar is built, maybe at home?
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Arash Ahmadi
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Re: Air resonance freq.

Post by Arash Ahmadi » Sun Apr 14, 2019 7:11 am

Beowulf wrote:
Sun Apr 14, 2019 2:06 am
Listen to "Antigoni Goni meets Hauser" with the discussion and sound for the 1940 Hauser I (from around 5:40 on):
Wow D! :D I didn't really enjoy the sound though. As Miles explained in the video and Chris here, it affects the trebles and that's the trouble. It would be interesting though, if a member of the forum who has guitars with different ARF could make a comparison video or audio.
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Arash Ahmadi
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Re: Air resonance freq.

Post by Arash Ahmadi » Sun Apr 14, 2019 7:13 am

astro64 wrote:
Sun Apr 14, 2019 3:04 am
The air resonance is not going to drop much with aging. To obtain a significant change in the frequency you could e.g. thin the top (something that could happen if you sand it down significantly in refinishing the instrument) or add sound ports. The reason the older guitars tend to have lower resonance is because they were built as very light instruments to begin with.
Then Steve Connor guitars should have a very low ARF with those huge sound ports, right?
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Martin Woodhouse
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Re: Air resonance freq.

Post by Martin Woodhouse » Sun Apr 14, 2019 7:22 am

Adding a soundport will raise the air res frequency

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James Lister
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Re: Air resonance freq.

Post by James Lister » Sun Apr 14, 2019 8:19 am

Martin is correct of course - increasing the total soundhole area will increase the air resonance frequency.
Arash Ahmadi wrote:
Sun Apr 14, 2019 7:02 am
Thanks Chris, yes in that article I read it was explained that F# is the ideal ARF
There isn't an "ideal" air resonance, and the air resonance is only one factor in the tone of a guitar, but it does give the guitar an overall character I think. In general, a lower air resonance will give the guitar deeper, warmer basses - but as Chris says, the trebles can become a bit more challenging. I don't think it's correct to say that a low resonance guitar will have weak trebles, but rather that they are likely to be less bright. I have played guitars with air resonances at D# and lower, and they can have very sweet, beautiful trebles, but some players like a really bright treble tone, and you're not likely to get that.

I tend to aim for somewhere between F and F# on my guitars, although I'm interested in further exploring the area below E. Ideally you don't want the resonance to fall exactly on a scale note, and particularly not on the open E. A is generally a bad place to be (IMO) - an open string resonance, and no depth to the basses.

I do think it's useful for dealers and luthiers to specify the air resonance - it doesn't tell you everything of course, but it gives some indication of the character of the guitar.

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Michael.N.
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Re: Air resonance freq.

Post by Michael.N. » Sun Apr 14, 2019 9:18 am

Seems to me that it's one of those magic numbers that people want to latch on to so that they can finally declare that it's the absolute pinnacle of sound and anything other is just inferior. Which of course is drivel. The larger modern guitars that I make (which are small) come out at G or G#. It's perfectly true that the bass isn't quite as deep or as dark sounding as larger instruments but then again I would argue that it makes for a more balanced instrument. Better, best? No, you might just say that it's a different presentation.
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astro64
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Re: Air resonance freq.

Post by astro64 » Sun Apr 14, 2019 12:41 pm

Martin Woodhouse wrote:
Sun Apr 14, 2019 7:22 am
Adding a soundport will raise the air res frequency
Correct, I phrased it poorly. I said "change", not "decrease", but in the context as written it suggested a decrease.

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Re: Air resonance freq.

Post by Dave M » Sun Apr 14, 2019 4:53 pm

Beowolf thanks for reminding me of that clip. I just love the sounds that Ms Goni can conjure out of these instruments.
And the point she makes about having to learn how to work with a particular instrument seems absolutely right. Definitely something to bear in mind when one is trying out guitars, and indeed trying to evaluate one's own efforts.

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Beowulf
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Re: Air resonance freq.

Post by Beowulf » Sun Apr 14, 2019 5:12 pm

Dave M wrote:
Sun Apr 14, 2019 4:53 pm
Beowolf thanks for reminding me of that clip. I just love the sounds that Ms Goni can conjure out of these instruments.
And the point she makes about having to learn how to work with a particular instrument seems absolutely right. Definitely something to bear in mind when one is trying out guitars, and indeed trying to evaluate one's own efforts.

Dave
You are most welcome Dave. Antigoni Goni is a marvelous guitarist and she is absolutely right. Here I am a year into learning about my GC82S and only now do I feel that I can really begin to work with my instrument and all it has to offer. Interestingly, I find that a new car takes me about two years to really "groove" it. :mrgreen:

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Arash Ahmadi
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Re: Air resonance freq.

Post by Arash Ahmadi » Sun Apr 14, 2019 5:30 pm

Thanks everyone for your explanations and examples!
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