Guitar Intonation Physics

A crash course on the underlying physics behind guitar intonation.
Achieving great intonation on a guitar can be a tricky task, involving a number of influences many players may be unaware of. Here we try to give at least a brief glimpse in to the complexities a luthier may have to consider when adjusting a guitar's intonation.

[@XHuntinatorX]

Ok, this should be required viewing for ALL luthiers and guitar techs!!! Finally a satisfactory explanation of intonation. Thank you!

[@abates226]

Nice to see someone that knows and isn’t afraid to share the long answer.

[@midlifemotox]

I've been playing and working on guitars for 45 years. I've worked thousands of sessions and live shows for some of the biggest bands in the industry. Been there,, done that. The information presented in this video is the best, real world advise on youtube.

[@ColocasiaCorm]

Are you bragging?

[@midlifemotox]

@@ColocasiaCorm Yes,, Yes I am.. Are you hiring?

[@ColocasiaCorm]

@@midlifemotox no you idiot

[@midlifemotox]

@@ColocasiaCorm A feeble attempt at relevancy in a KZbin comment? Rather pathetic. Obviously not much going on in your small, little existence. Good luck. HaHaHaHa...

[@LukeA1223]

@@midlifemotox minds are so cute when they're small, don't you think?

[@boshi9]

Best video on the subject of intonation on KZbin! So many techs explain this wrong.

[@krauz111]

you should really do a tutorial for setups, this seems to be the best guitar tech channel on youtube

[@RollYourRock]

YES! - Please...

[@MrWolfheart111]

Lots on the tube (setup). Intonation is the hardest to grasp for me.... its the last piece of the setup puzzle.

[@bobsegar1242]

That’s basically what the video is 😂🤷🏻‍♂️

[@CheapPartscaster]

Knowing how to intonate a guitar, this is excellent information explaining, what it actually is that you are doing. Thanks a lot. Very much appreciated! Instantly subscribed.

[@kevingriffin1768]

Wow! I've just made my first guitar (retirement project!); with a science background I mostly understand this but my head hurts from so much information in a short video. Thank you. I need to bookmark this and watch it several more times. 👍👍👍

[@ejuncos]

Best video on intonation physics and more I've ever watched!

[@learnerlearns]

Studio guitarist here: All the information in this video is correct and true. It is trivially common for pro players to physically coax some notes & intervals flat or sharp, either as single notes or within chords. That also affects which chord voicings and subtle tuning tweaks we apply for various styles. So far, this is the ONLY KZbin resource I've seen that is both factual and reasonable. You can attribute that, in part, to the fact that this guy is NOT trying to sell you some new gizmo, gadget or gimmick. Rather he focuses on helping you understand the physics so you can practice compensating for your needs and ability. I am obliged to point out he narrates well and requires no script to be coherent. That indicates several things: One- He has a command of English which shows he has a grasp of LOGIC. Two- He understands the subject thoroughly. Three- He is confident because he has studied the subject for years, so he does not "hmm" or "uh" or say "like" or "you know." Pleasantly, he does not smack his lips, sniffle or gasp for air as far too many presenters do. He neither rushes nor drones on too slowly. He speaks NOT with a tedious soporific monotone, but with the mellifluous voice of a musician. He speaks intelligibly with the clear calm meter of an expert because he IS ONE. Trust this man. Ignore the blathering legions of pseudo scientific impostors, especially those who try to "sell" you anything.

[@MrNickdino]

indeed it seems so that he does not sell a gimmick or a product, but he does implicitly advertise his guitar tech service. conflicting interests may arise

[@DapperHesher]

Or just retune, punch in, retune, punch in, retune, punch in.

[@theharvardyard2356]

bro you're annoying

[@flybybaby8008]

I greatly appreciated/enjoyed both the video, as well as your comments, as I found both to be extrodinarily factual and well articulated! Best video in regards to a deep dive into the how's and why's of intonation, and how best to achieve what's feasible, and what is impractical. It was truly a light bulb moment for me, a case of 'all things being revealed'.

[@nilsdesperandum]

David knows his stuff more than any other luthier I know. About fifteen years ago I was struggling to intonate a Gibson and, long story short, after feeding some measurements into a spreadsheet I found that the guitar was fretted using the long obsolete rule of eighteen. After posting my findings on the Seymour Duncan forum he actually rang me (and I'm in the UK!) and we had a long chat about it. He sent me loads of spreadsheets summarising the work he'd done on it, which was almost too much for me to take in...

[@klauscottonswab2322]

I learned so much from you, some stuff that intuitively was familiar and now I can "name", other things completely new! (I have watched this video now multiple times over the last few years, every time discovering new things.. ) Thanks!

[@9jmorrison]

Great handle, cottonschwab

[@NicklausSIR2]

Boy, it's the first time I actually hear the explanation about string stiffness and it's effect on intonation (why would you need to adjust your saddles is the scale length was exactly 2x the 12th fret distance ?). Having some knowledge in material science, I always suspected it was the reason, but never found some proper explanation. Thanks for clarifying this !! Also kudos for building these testing setups, they help understand the influence of different factors.

[@nicholasbrown1628]

Thanks David, you've cleared up some things for me that I've puzzled over for a long time.

[@jeffreagan2001]

Every guitar player should watch this video.

[@neilfradenburgh]

Sorry, way late to the party. This is an incredible video, combining and solidifying many concepts I have tried to piece together over the years. Off I go to search out any other gems you may have posted. Thank you!

[@danthegeetarman]

Best breakdown on intonation out there. This is great and informative 👍🙏

[@johnbohland]

Thanks for this. Still very informative listening 7 years later.

[@lukel2359]

A mind-expanding video which enabled me to see the guitar in a new light. Thank you for sharing your insight.

[@KBorham]

For me, a huge mystery solved! As a hobby acoustic player for 40+ years, my tone perception has grown so sharp as to detect these intonation issues, and it started to drive me crazy. Thank you for sharing this information in a clear and concise manner. I can kick back now and enjoy just playing my guitar again.

[@robpearson9526]

How I never seen this before, is beyond me lol. Over the years and many many videos later, I’ve really become non the wiser. This video is by far, the most informative, and succinct explanation of intonation (not to mention, many other nuggets of great information) I’ve ever seen! So glad I discovered it. Better late than never🤗! Awesome job, thank you!

[@aipsong]

Years of knowledge distilled into an excellent video - many thanks!!!

[@FriendM2010]

Hello from SoCal by way of Ann Arbor (Birth place) went west in 1978 👍. Dan from StewMac has an Ann Arbor connection too. 👍 I purchased an HD28 new in 1977 outside Ann Arbor before my journey to SoCal. I am nearing retirement and I know this is hard to believe, I am YT educated enough now to realize my baby had the bridge put in wrong place by 1/8 inch and intonation is sharp on every string.. Sad to thing of the surgery the guitar needs to correct, saddle needs to move back 1/8 inch, no room ... Apparently, it was a Martin production error during the 70’s... I got through your entire video and my brain hurts, subscribed ... 👍 Cheers, Matthew.

[@christopherlong354]

This is an incredibly informative video. Well done! You have provided concrete concepts to describe some nuanced issues I have experienced in the 11 years I have been playing.

[@Yu2beFool]

Now, that is the proper explanation that I wanted to hear! Thanks a lot.

[@ivanpejovic382]

Thanks, David! Straight to the point on every aspect!

[@alvisgrady3357]

Excellent clarity and delivery !

[@JetEdz]

Very well explained! Thank you for taking the time to create this video.

[@acousticguitarcanada]

Just discovered this video again... love when Science meets Art.

[@lordwalnut]

David thank you for a great video. You are extremely well spoken and I appreciate all this information you provided.

[@fraserwing8744]

Brilliant video. Thanks for sharing with the world.

[@innocentoctave]

This is a really good video: detailed, clear and myth-busting.

[@orlandofernandes4790]

Never heard someone with so much knowledge. Thank you so much David

[@sofacityguitarshop5523]

Excellent! Thank you!! Guys like you help all of us who do our best to satisfy customers with detailed, quality work suited to their specific desires.

[@MrUSFT]

Just watching this in 2020. Such a great video. This answers so many long standing questions I've had about why things sound the way they sound and shake out the way they do. Thanks for sharing your knowledge!

[@ANPEQ2]

Fantastic video. Very helpful information.

[@wtpfeffer]

Really excellent - The best explanation I've seen - by far - of the factors influencing pitch and intonation in a guitar. Thanks!

[@darwinsaye]

I feel like I just took a full course. Thank you for so much excellent and detailed information.

[@whocares.20]

That was the absolute best explanation indeed. Precise, accurate real world science.

[@sachinkarne1423]

Awesome, you explained the intonation so well. Thank you.

[@squibism]

Amazing detailed high-quality information. Thanks!

[@caniican]

outstanding video thank you so much for uploading my friend. I love KZbin to see how people grow their skills after years of sticking to something and this man is right on perfect example keep up the good work

[@patrickford9615]

Thank you! I've heard of stretch tuning. I had a piano tuner explain what he was doing on my piano as he was doing it. He liked to talk so I got to hear alot. He explained what stretch tuning was but attributed it to the human ear. Your explanation of the physics is more satisfying. Thank you.

[@ericdenton6664]

Thank you for all your work and research and sharing this aquired knowledge with us around the world. I assembled my first strat 38 years ago. I spent most of those years studying music and playing rather than the physics of the guitars construction and setup. Of course I figured out that a properly cut nut was key to a great guitar years ago. Now after all these years I'm learning more about guitar electronics and the physics than ever thanks to channels like this. Bravo

[@thatguy431]

As someone who will never pay for a guitar tech, you are a gem! I can't thank you enough (except probably through monetary compensation....heh)

[@theonlyabsolute]

Excellent video

[@Ahmedgrooves]

I tried applying pressure while fretting pushing the stting towards the bridge to make a sharp note flat and it works PERFECT and very easy! really this is one of the best tricks I have learned and i believe you should mention it again in your future videos !

[@ericboreen4040]

My compliments to the chef. This video was very easy to listen to. I'm not a guitar player but I wanted to know what intonation was and this exceeded my expectations in a satisfying way.

[@louismarino1171]

Thank you; that was amazing! I knew you knew your stuff when you said adjust your intonation in playing position. I have had professional luthiers intonate my guitars on the bench, and I always have to readjust it when I play it. I usually adjust my action first, intonate the bridge at the 12th fret, then adjust my pickups.

[@tdrake59]

That was packed with content. I learned quite a lot from this. I've been wondering about the earvana system. Your video has really helped my understanding of this topic.

[@vladartov2817]

Thank you very much for your work and your excellent explanation!

[@paalbrudevoll6330]

thanks for a brilliant engineering approach !

[@geraldponce8336]

As a home builder modder. This is very useful information.

[@himax000]

Kudos for your video series. Absolute good stuff!

[@heinofauch]

This is really one of the best channels for all these guitar topics. It seems you stopped it since there are no newer videos uploaded. I would appreciate if you continue again.

[@nancieredekop1846]

Your overall knowledge of intonation was much appreciated! I'm an older player, still active who plays a wide variety of styles on a wide variety of guitars. A few years ago I got turned on to the Buzz Featon system, but as you pointed out it also has inherent limitations. Equal temperament would be a wonderful thing, but almost impossible to achieve on guitar. Went through a similar problem in tuning my piano, "auditioned" several tuners until I found one who understood the problem (and wasn't prejudiced against a guitar player). In a perfect world we would all be in tune, in the mean-time we'll keep looking for a "perfect" solution! Thanks for your post.

[@nanaandbump.]

Wow this is fantastic, thanks for sharing your expertise! I've always struggled to wrap my head around how an octave harmonic could possibly be out of tune from the open string, from like a physics standpoint. In my mind, its just half of the length of the string, so it should just be a perfect octave. Your contraption where you halved the length of the string was pretty eye opening and helps me understand a bit better. I'm definitely gonna be checking out your other videos, thanks again!

[@thatguy431]

In physics it's always an "ideal" string. Bastards never taught us about stiffness!

[@maverick.gaurav]

Loved the video, Thanks for explaining with so much patience..

[@oinkooink]

Great analysis and knowledge. Excellent stuff :)

[@Chrisbell804]

Thank you! Thank you! Thank you! You are the first person to explain temperament properly. That makes you the only Person besides me that I know who understands. I have been using my whammy bar to flatten some notes and my finger pressure and slight bends for the rest of the notes. 🎸🎭🥁🕊🏴‍☠️😎💜🌎

[@ssdassure9350]

What an amazing video, I learned so many new things!

[@TheFarout69]

Your the best at getting to the tech- Thank you. I'm always looking for a good trick or explanation and you always provide new insight and ideas. BTW- you are dead ringer for a good man and a good friend of mine, who is a fabulous harp and horn player and an expert aficionado of medieval instruments. That aside- when I adjust the general intonation, I measure from the 2nd or 3rd fret to the 14th or 15th respectively. And surprisingly, the "zero fret nut" option often resolves many issues regarding this always imperfect adjustment, especially on a hard fingerboard radius like 7.25. - Great video!

[@1rudymartin]

Fantastic explanation, Please more more more. Regards. Rudy.

[@stratocasternut]

Best comprehensive presentation of this topic I've come across in almost 40yrs, Thank you! Next time you're wondering what to do with your copious spare time, I'd suggest you discuss your views on the Locking system, i,e, Floyd-Rose, or the likes as opposed to traditional fender system. I've heard a few professionals say that their tech can setup their fender bridge so it doesn't go out of tune. Surely a complex subject, since the entire saddle reference changes, the tension on springs, the nut and string type all compound the issues.

[@seamanjive]

Wow, superb analysis, thank you.

[@joecaner]

This is great stuff! There was a time in my life when I thought that all guitars were always out of tune no matter what except for a fortunately made acoustic guitar that I did most of my compositions. I would spend hours tweaking intonation. I always loved the expressive nature of the guitar, but it came at a cost where everything effected intonation. And then, something just settled. Perhaps my guitar became in tune because I became in tune with my guitar. My guitars are still slightly out here or there, but it doesn't really matter because I roll with it and play off of it in real time and it just becomes part of the music. The freakiest thing I ever heard was a piano player who seemed to be able to do this when playing the most egregiously out of tune pianos. He was miraculous. I don't know how exactly he was able to do it, but he was able to coax music from pianos that just sounded like jangly trash when anyone else laid their hands on the keys. In the end, it's all about touch regardless of the instrument because all instruments are just nominal representations of an ideal that one holds internally to one's inner ear. Of course, you better believe that I set up the neck, adjust the string heights and set the intonation as closely as I possibly can. Old habits die hard, and I'm always looking for the sweetest sound I can get.

[@angelopacifici1546]

Thanks for this fantastic video and deep information

[@bobyk87]

Thank you, really great video with tons of worthy information.

[@Crazy_Dave]

Awesome, thank you so much for sharing. 👍

[@HeiJuLau]

Really great lesson, thanks!

[@erichelsinkimusic]

this video is freaking amazing. I have mystic flat notes that appear in flat top guitars sometimes - it could be explained with nearby (body) resonance pulling them down. Thanks for the video!

[@Jamesfoofighter]

Excellent informative video. Thanks

[@blueyepaul]

Excellent, well presented

[@mikeg3660]

Wonderfully complete and sound coverage of a complicated subject. I have to admit I was hoping for the magic dust at the end. Sounds like you’re saying it’s already there if your guitar is properly set up which is, of course another complicated subject. Thanks again, longtime subscriber.

[@bigpiper2103]

Thank you so much for sharing your knowledge! You've helped me tremendously, as I was positive my guitar had a problem, but had no idea what caused it! Now I know! Perhaps other people can learn from this! I used to play baritone scale (27") 7-string guitars in drop A with no issues, but switched to a shorter scale (25.4) due to its comfort for playing leads. I'm also a pretty hard-hitting player, so to keep the low A stable on attack, I went with increasingly higher string gauges, but the weird oscillation problem was not being alleviated. I blamed it on the short scale/string not thick being enough and went with an even higher gauge. This was until I reached 75, which is why the fundamental frequency was stable on attack, but the powerchord on open strings sounded horrible. I had no idea why, people I asked said either I was imagining it or blamed it on pickup height or wood resonances. Now I know the problem was the stiffness and the resulting dissonance between the strings' harmonics, which is what bothered me. I went back to 70 and although I'm getting a bit of pitch drift on attack, the discordant harmonics have drastically improved. I'm now working on lighter attack and considering getting either an Evertune bridge to play with lower gauges or getting a new, longer scale guitar altogether. Thank you again for saving my sanity, and if you have time, would you please share your opinion on the optimal string gauge for drop A on the 25.4 (can it sound good at all) and the Evertune (is it going to help me).

[@dennisbronson3058]

Great video . Good explanations . thanks.

[@koendelvaux]

This was great, thank you. Certainly beats my calculations where I used triangle hypothenusa to calculate the difference in string stretch from fretting low and high on the neck to establish the ideal nut compensation.

[@WageSlavery]

Wow, for over two decades now, heavy metal guitarists have explained that drop tunings "just sound better" with distortion, as opposed to standard tuning. The lower the pitch you tune to, means that you need thicker strings to get the same tension. This increase in thickness has a side effect of increased stiffness. Increased stiffness leads to sharp overtones, which would clash with the fundamental frequency. But in the game of distortion, the more dissonance between the tones and overtones leads to a "bigger, heavier" clash in distortion, the desired effect.

[@andrey.tkachev]

This is a brilliant video

[@rickkernell2486]

As an engineer and novice guitar player, this presentation is exceptional.

[@repeatoffender9902]

Yo you are the man never have iv been so intrigued in a intonation video and learned as much you are a awesome teacher thanks

[@A2Guitars]

Thanks - you have plenty of great resources in New York of course. Evan Gluck in Manhattan, Mamie Minch in Brooklyn, Larry Fitzgerald on Long Island, no shortage of great luthiers out your way!

[@notrance]

This is really helpful. I hope you have time at some point to do a demo of creating a new nut, or slotting a replacement nut. Thank you!

[@redguitar12]

Great video!

[@zomesargentina]

ENLIGHTENING VIDEO!

[@acousticguitarcanada]

Wonderful lesson... thank you!

[@2yugen2]

Great video.

[@guitarshackbr]

Excelent vid. Thank for sharing yours knowledge.

[@edwinbond5995]

Thanks for that David. I like to think I have a good basic grasp but that was revealing.

[@Noone-of-your-Business]

Wow. I didn't know *any* of this. Thanks so much!

[@helgeheggset3335]

Fantastic, I learned a lot here! Subscribed right away :)

[@Chemist1076]

great solid video

[@caseykittel]

oooo. compensated nuts at 12:15! nice info all around. amazing.

[@bee.normal]

This is a great video. Subcribed!

[@WimBlock]

Thank you for sharing you're experiance with us

[@fraserwing8744]

As a hobbyist musician, coming from a mechanical background - where everything has to make sense, to a simple one + one = two foundation - this video is just pure sex, as far as my developing interest toward acoustic characteristics and tunings / temperament. Thanks for making this gem!

[@richsackett3423]

On open-back nuts, I cut the slot inward so the nut angles away from the bridge at about 5 degrees. Sounds great down there and still fine with a capo or up high. On bass nuts, it helps if you bevel back the front of the nut slightly.

[@BellTunnel]

This is great. Please make more videos. Subscribed.

[@ashwalk85]

Thank you so much! I learned a lot!

[@ellerbrock-guitarandbassre6421]

Brilliant!

[@sempercompellis]

i am so glad i stumbled across this video

[@atlgtrman]

This is by far my favorite video on the physics of string/intonation. I wished you would have tested the intonation at the 1st and 7th fret also to show how much stiffness at a fixed point effects the pressure required and subsequent sharpening of the note. Being a recent Plek owner, I'm very fascinated at these properties and how a string vibrates with slow motion photography. Have you ever seen any of their vids or even the Santa Cruz video using the Plek slow-mo footage at the beginning? Please keep these videos coming!