Official Luthiers Forum!

Hi my friends,

Hope you’re all doing well.

I’ve just started a new build (I’ll share progress soon), but in the middle of it I ended up going down a different path.

After around 18 builds, I’ve reached a point where I’m no longer satisfied with getting a great sounding guitar “sometimes”. I want to be able to get my best results more consistently.

Like many of you, I’ve been reading more about tap tuning and deflection, trying to better understand what’s actually happening in the plates rather than relying only on feel.

That led me to start building a tool for myself, and over the last ~6 months it has grown into something I now use regularly in my own workflow.

What it does, in short:

– Measures tap tones (longitudinal / cross-grain, decay, Q)
– Allows deflection testing (both full plate and 8" beam)
– Calculates normalized stiffness and structural values
– Lets you compare plates and reuse values across builds

The goal is not to replace intuition, but to support it — to make things a bit more measurable and repeatable from one instrument to the next.

I’m quite happy with how it has worked for me so far, but I would really value feedback from other builders before taking it further.

If anyone here is interested in testing it, let me know.
(Mac only for now, and it’s a 7-day test version.)

What I’m most interested in hearing is:
– Would you actually use something like this in a real build?
– Does the workflow make sense?
– Does it feel useful, or unnecessary?

I’ll keep the number of testers small so I can actually follow up properly.

Would really appreciate your thoughts.

All the Best your Buddy Lars.

Below you can see some short of what it can do.. some features are expanding to give more options and we can add out own inventory to the App aswell , name each piece and it will show in the top side view. Different kind of Deplection styles depending on what we as luthiers use,, aswell as Tonal analyzis. IF not using this way to tune your guitars, it is a super benefit as a comparizon tool, but most of all to get as much some result on each build. left top side Audio explanation for each major feature with detailed explanation so both experianced builders aswell and non experianced builders can benefit from it. when Audio is closed, you can add photos of your own guitars or other photos you might have use for during the build. To the left of the audio (View) will later be photos for each feature so a user with less experiance can actually see the feature in use to better undeerstand and have it easier to implement it. Let me know what you think..
Ps/ the 4 photos are not showing that app is 4 pages long it show photos with different features open, so you partly can see what it can do !

That looks quite interesting but that’s a lot more info than I personally feel the need to collect…

the 4 photos only show the features opened and closed so you can see what the app can do.

Yes there are lots of features. But they are not there so you "must" use them you might only need to use Deplection testing the top plate and leave other features, others can use more and less. Features are there so The option is there if needed.
Personally I test deflection on free top, then after Bracing deflect with braces, and I then also Do tap tuning.. by getting the Hz from it and all measurements are then saved so next time if you made a fabolous guitar you can go back and place your numbers in from that build and you can now make the new buold match the old and if you dont have target number for your deflection, then you now have that from your previous build. For those who already have set deflections Targets just place those in settings and the app follow this as its Targer and guide the user to get to same point not needed to use paper and pen for each step of the build all it handles by the program.

Lars, I saw your post and thought I would comment, however I'm a pretty poor person for that task. I'm a hobby builder, pretty much at the end of my career (thinking about how to close down my shop), I only come around OLF once in a while, and like Ed says, that's way more information than I would want.

However on my last few builds I used Alain Lambert's "luthier's spectrum analyzer" and found it very helpful as I worked thru voicing my guitars. My last guitar was a carved top archtop (L5 inspired) and was guided by Bob Benedetto's book. The software let me follow the changes in response as I did the various voicing operations - carved plates, braced, cut f-holes, and so forth. The encouraging thing for me is that the resonances shifted as Bob predicts and I could see graphically what I thought my ears were telling me.

I also used Alain's software almost every time I made one of those changes that should result in a change in the sound - maybe someone wanted a new nut, I would take a couple of spectrums before and after the change and could show the owner what we thought we were hearing.

Unfortunately Alain has shut down his website and support for the software. He still answers e-mail requests for support (which is something you should think about if you decide to go public with yours). I continue to use it, a friend just made a new bridge for his mandolin and hears HUGE difference, we'll see....

I would find something like that very useful, keep it on my laptop in my shop. Use the mic in the laptop, as long as I keep everything else the same I'm mostly looking a trends and changes. Its really just a fancy version of Audacity optimized for a luthier's workbench.

Good luck with whatever you decide, it looks like a pretty nice tool.

Hi Freeman, good to hear from you, thanks for your message !. Yes I am glad to hear you had use for the Alains Spectrum Analyzer. Why do you say your at the end of your career ? We all get older, but as long as the torch is lit we are still 18 years old just the darn skin that dont follow along as it used to haha. Man it suck getting older, But, I remember an old friend of mine who is now no longer with us Bob Johnston, the producer for Bob Dylan, ( I was signed to him as an singer songwriter many years ago.. we was talking on the phone and he told me that he just had gotten back from hospital from a heart attack or similar. Ambulance came and he said he locked himself into the toilet, because he still had 2 calls to make hahaha. Then he opened the door so they could take him. Man, he was like 24 all his life. One day he had flew here to me in Sweden from Nashville, we was in a studio recording, he was the producer. he had a crutch when he was walking because of a scrapnel in the leg from the war ( dont know wish) we was up all day, all evening and into the night recording. 10 musicians and all, everyone started saying, "maybe done for the night" all wanted to go home, Bob went out (it was -10 middle of winter) he came back filled with snow in the beard water dripping.. said...That it, now im awake again, lets continue hahaha. Man he was younger than everyone in there.
what I am trying to say is. IF you meant end of your career regarding sitting on a dest for some boring desk job. then i am with you.. if its end of carreer building guitars.. then dont stop. make it into a profession ( since you said your a hobbyist). I mysolf is 53 now some say 54, I dont agree haha. Anyway, Thanks for your message ..IF you have a Mac laptop or stationary, let me know and ill send you a copy of this program.. So you can test and see if you like it !!

I am also working on another program for outlining the design for the guitar body. you can take any guitar body you like and the program outline that guitar automatically, then from there one can tweek it into ones own design. This will be intergrated into this program above. So one can design a full guitar in the program, even let the program "hear the braced top and know how it will sound (theoretically.) . Since I am a builder aswell I hope I know a little on how It should work from the perspective of the Luthier.

Anyhow.. Again Let me know if youd like to try it out.. (only on Mac so far.. )

All the Best Lars.

Ps/ for anyone wanting to test the program to give me some output of it and suggestions, give me your emails and I will send a copy.
It would help me alot to know if the program is good or needs improvements.

Good to hear from you Lars, that's a very deep dive into left brain lutherie.
I'm nearing the end of my building career, and I've settled on a simple method of getting some consistency in my builds by measuring long grain stiffness (tops) and soundboard rotation before closing the box so I'm not a candidate for testing your methods, but it's great to see you are still building successfully.
Best of luck!

_________________
The name catgut is confusing. There are two explanations for the mix up.

Catgut is an abbreviation of the word cattle gut. Gut strings are made from sheep or goat intestines, in the past even from horse, mule or donkey intestines.

Otherwise it could be from the word kitgut or kitstring. Kit meant fiddle, not kitten.