Tuning Semi-Hollow Electric Guitar Chambers

[u6crash]

Building my own guitar is something that has been on my mind for years and just hasn't happened yet. I finally added it to my bucket list with a due date so I'm trying to get my ducks in a row. As things go, the two original designs have in mind are semi-hollow electrics. The closest production equivalents would be a Thinline Telecaster and an ES-335. However, I feel like I recently read somewhere that the resonating chambers sandwiched between the top and the back should be tuned. Is this correct? How does one tune a sound chamber during construction? I feel like one of the options to not turning the sound chambers was to have multiple weight relief relief chambers instead of one large chamber on each side. Does anyone have any thoughts on this that might help me out?

[WRGKMC]

 

However' date=' I feel like I recently read somewhere that the resonating chambers sandwiched between the top and the back should be tuned. Is this correct? How does one tune a sound chamber during construction? I feel like one of the options to not turning the sound chambers was to have multiple weight relief relief chambers instead of one large chamber on each side. Does anyone have any thoughts on this that might help me out?[/quote']

 

That's a pretty complex goal. So much has to do with the materials and construction, wood densities etc. Few even bother going that route and leave it mostly to chance. Even your major manufacturers have huge variances between the same builds because the wood grain is different for every one. That's why some guitars are sweeter then others.

 

I've done allot of experimentation myself. Its fairly easy to test your build and measure what the bodies resonant tone is once its built. Trying to target a specific resonant tone before you even begin to build an instrument would require an Einstein to figure out all the many factors that can cause it to change. You can test it with contact mics on the body and recording the bodies tap tone into a DAW recorder. You can then view the resonant tone of the wood with a Frequency analyzer and see what the strongest peaks the wood produces.

 

From there I suppose you could use scrapers and sanding on the outside of a body to raise the resonant peak and target a frequency response.

 

On one of my last builds I built a semi hollow Tele type build. I did test the body this way and found it has a resonant B note just by luck. This is higher than most other guitars I have and I suspect its because the top of the body was clamped to give it a curved top. Its also built with antique wood which was over 200 years old and quite petrified. If it had more moisture in the wood, the overall resonant tone should have been lower.

 

I'd say a body that has a resonant peak close to one of the strings tuned to concert pitch will probably do fine. I'd also say say don't worry about it until you have the entire guitar built. Even the hardware mounted to the body changes the resonant tone so there's no way of predicting what the outcome may be during the building process. If you use good materials it should still sound fine no matter what you wind up with.

 

You could leave it unfinished until you are sure it sounds good, then use sanding and scraping as a method of changing the density. There again, just adding more layers of finish will change any fine tuning you may do so why bother.

 

There's no way you'll access the inside once it's built either so I really wouldn't worry about it much, especially if its your first build. In a list of things you should worry about with all the things involved in learning to build a guitar, worrying about its final resonant tone is like 9999.9 on a lost of 10,000 other things before you'd even consider going there.

 

 

[u6crash]

That's some good insight, thank you! I think in light of this information I just won't worry about it too much.

[Mr Temporary]

The math makes my head hurt, but from what I understand, I'd have to agree with WRGKMC that it's practically impossible to predict the effect of dimensioned air chambers on how the whole guitar is going to respond once it's built. You can make a few dozen, then start making systematic changes and try to learn something from that, but even then you're probably going to only get in the ballpark of whatever target your shooting for. Never mind what happens when you plug it in, mess with the gain and EQ settings, and stand in front of it. Also, who's to say what the right "ballpark" is in the first place - I may like resonances much lower than you, vice versa, etc.

 

So, I also would suggest that you not worry about tuning the air chambers on your first few guitars. If anything, I'd suggest giving some thought as to what effect the chambering might have on the ability of the guitar to balance on a strap and/or your leg.

 

You could try doing as WRGKMC suggested, which is to refine the response while the guitar is "in the white". This is what John D'Aquisto used to do with his archtops. He'd get them built, and before finishing them he'd string them up, then carve/scrape/sand the recurve until it sounded the way he wanted. I'm sure that after building so many he got to the point where he'd get it where he wanted it, then go a little further to compensate for finish, but I'd have to check that to be sure. Some violin makers employ a similar process. Then again, he was a freakin' master and working with mostly acoustics, so I'm not sure that even this is worth your while, especially for your first instruments.