intonation on single cones

[djsbluesbar]

Hi people, quick question, i have a single cone resonator, "vintage amg1" new bridge cone etc. playes great but the intonation is out. Is it ok to turn the bridge/cone to create an angle until intonation is better?
Thanks
Dj

[mikevernon]

Hi Dj
Yes, a few degrees anticlockwise rotation of the biscuit (and therefore the saddle) should give a reasonable approximation, but it's a process of trial and error.
The thickness of the saddle also allows a little more adjustment by careful shaping of the wood to give increased length to the bass strings.
Incidentally, can somebody tell me how good is the intonation on new NRP guitars? And has anybody used a compensating saddle on a resonator as used on any half decent acoustic or electric guitar?

[Michael Messer]

Hi dj,

If the intonation is out on your single cone guitar, you can twist the bridge, but if you do you will have to re-angle the string slots. Otherwise the strings will be doing a slight dog-leg bend at the bridge, which in my book is not right. This is not normal practice.

You can move the bridge/cone backwards or forwards to help correct intonation problems, but that is about all you can do without performing major surgery on your guitar. By major surgery, I mean having the neck re-set, which is the correct way to do the job on a resonator guitar. The intonation will never be absolutely spot on, it isn't on any guitar, but resonators are never quite there. Get it as good as you can and don't worry!

I do not believe that compensated bridges work on resonator guitars. I have tried it on one or two, but I don't se the point. On a single cone guitar the bridge saddle must sit directly over the centre of the cone or eventually it will damage the cone. Mike's comment about thickness of the saddle is about the only successful way of doing it.

Mike - the intonation on National Reso-Phonic (NRP) guitars is absolutely fine.

Professional musicians have been performing and recording with resonator guitars for the past eighty years. Just enjoy them!

Anyone else got any thoughts on this subject?

Shine On
Michael.

[robn]

Hi Dj,

Most of the bespoke luthiers (and a few of the budget luthiers ) set the scale length a fraction longer from the 12th fret to the bridge than from the nut to the 12th fret. This as good as much solves the intonation problem on reso guitars (not 100% accurate, but good enough) It just takes a bit of thought and maths when setting the neck!

Also, the more you bring the action down on a reso the less of a problem the intonation issue will be. Unfortunately, many budget reso guitars do not have enough spare capacity build into the break angle over the bridge or neck set angle to drop the action without loosing too much down pressure on the cone and screwing up the tone and volume

That's reso guitars for you - designed and built like tractors (albeit art deco tractors!) but requiring the finesse of a F1 tune-up to get them running properly

Playing around with your bridge angle and moving the cone to the rear of the cone well should improve matters on your AMG1.

Robin

[djsbluesbar]

Thanks for commet guys, its only a slight twist i need to do to get the intonation right. no dog end angles needed. its a good guitar for the money, made people jealous who paid over twice as much and thought i had something more before seeing the headstock. just wanted to know it wasnt a sin and would do damage to the cone etc...
thanks again
Dj

[Deleted]

May 5, 2008 16:54:00 GMT mikevernon said:

Incidentally, can somebody tell me how good is the intonation on new NRP guitars? And has anybody used a compensating saddle on a resonator as used on any half decent acoustic or electric guitar?

Hello. About the intonation on Nationals; On my Model-D (spider), the intonation is simply perfect, never touched it, this was how I took it out of it's case after buying it. And it has stayed that way, although I never change strings. On the Delphi, it's almost perfect, only the high E is slightly off. And now, my Trovador. Also, almost perfect, here the low E is slightly off. But, this is about your compensating saddle question: at the B-string, they cut out the saddle, and glued a small piece of wood to the back of the saddle on that spot, so in this way making the stringlength of the B longer. I bought the guitar new, so I guess it was done in the National factory. After a while I realised this is an amazingly simple way of creating a compensated saddle on a reso, and it works too.

Regards, John.

[Gerry C]

Long ago I was given some (only slightly facetious) advice about playing if the string went slightly out of tune - not unusual if you bending strings - or if the intonation was slightly awry. The advice pertained to electric guitar but it works for acoustics and resos too: "Just hit the damn string and bend it till it fits!" ;D

Cheerily,

Gerry C

[mikevernon]

Hi John (Windmill). That's interesting. So some Nationals do leave the factory with compensating saddles after all. Can anybody confirm this? Glueing an extra piece of wood on the back of the saddle seems a crude way of doing it though. I wonder why they don't just shape the saddle to allow for the difference between the wound and plain strings. On my regular acoustics the step back from the top E to the B string is 2-3mm so it should easy enough to accomodate that in a 3-4mm maple saddle.
Surely the standard factory set up on NRP guitars also includes a slighly angled saddle? And as Robin points out, the degree of compensation, and hence the saddle angle, also depends on the height of the action.
Mike

[tark]

I'll probably get flamed for this, but I make and sell adjustable bridges for setting the intonation on resonator guitars.

Rotating the bridge may improve the intonation on the low strings at the expense of making it worse on the high strings. Even shaping the saddle or carving the string slots in reverse is not sufficient on most resos to achieve proper compensation. This is because of the heavy string gauges, open tunings and often high action on these guitars. This is why you find NRP gluing extension wood strips to their saddles. I don't know if I had anything to do with it or not but NRP started modifying their saddles shortly after I exchanged emails with them on the subject of intonation and sent them one of my bridges.

I'm afraid I have to disagree with Michael; in my experience offsetting the saddle on the biscuit to compensate a resonator guitar will not cause any damage to the cone (NRP seem to agree). In any case as far as I can see moving the saddle away from the nut (leaving the biscuit where it is) actually helps to balance the pressure on the cone. This is because as far as I have observed the break angle of the strings behind the saddle is steeper than the break angle in front. This means the tension of the strings is trying to rotate the biscuit - pushing the nut side down while the tailpiece side tends to lift. Moving the saddle back a little shifts the pivot point and more of the biscuit is being pushed down.

Compensation is a bit more of a compromise on resonators played with a slide than on normal acoustics designed to be mainly fretted. Slide notes do not need compensation. Many resonator guitars are built with the actual scale length equal to the design scale length (i.e. no compensation). This seems partly because the overall design does not lend itself to compensation and partly because the makers may assume the guitar will be used mostly for slide and the player will not want to fret notes high on the neck. NRP are one of the few companies that do shift the neck a little way further from the tailpiece to provide a rough overall compensation. Robin I think posted a picture a while ago of a Chinese built guitar with the saddle slot routed off centre on the bicuit to provide compensation. If you do compensate a resonator for fretting then you have to live with the slide notes not being directly over the frets. Personally that suits me fine because slide notes really have to be played by ear and I love the sound you get when fretting and fingerpicking a resonator thats properly intonated.

[snakehips]

Hi there !

Just to add, my NRP El Trovador also has the extra piece of wood behind the saddle for the B string.
I'm not sure if it is this or the new NRP "vintage styled" tuners (available on their website) that is causing me difficulties getting and keeping the guitar in tune. My ears are very very sensitive to slight out of tuneness. Like when you tune it so it sounds perfect for an E chord but then it sounds way out, playing a C chord.

[Michael Messer]

Hi Tark,

You won't get flamed for promoting your product on my forum, but you will get flamed for believing that it is necessary to fit a compensated bridge saddle to a National or Dobro guitar.

I am afraid that I disagree with what you have said. I have spent the past 35 years of my life playing, recording, performing with, and collecting these instruments. In that time I have spent days, weeks and months in the company of the world's leading experts on this subject (players, makers and collectors). In all that time and with all those people, I can hardly remember any discussions relating to trying to improve the intonation of these instruments. A properly set up resonator guitar in the hands of a good player will and does play in tune.

There have been many great players over the past 81 years who have played single cone & tricone guitars without a slide and perfectly (if there is such a thing) in tune. Blind Boy Fuller, Oscar Aleman and Bob Brozman, are three names that spring to mind. I picked those players intentionally because their style of playing without a slide in EADGBE tuning requires good intonation. As much as I love Son House & Bukka White, there is no point in bringing their names into this discussion.

Sadly, John Dopyera and his brothers are no longer with us, but I have a feeling they would have been on my side of this discussion, otherwise their designs would have been different. I think John Dopyera would have eaten you alive for some of your comments about break angles & intonation.

With respect!
Shine On
Michael.

[Mark Makin]

I have to agree with Michael. This argument is similar to the ones you have with people who own classic sportscars. They spend every weekend underneath them but never drive them anywhere.

I have owned over 60 Nationals and certainly many things have been in need of adjustment and repair - but NEVER have I worried about intonation. I think GerryCs comment about pushing it till it meets the note you expect to hear is spot on!!

Lets just enjoy playing the things!

[Deleted]

May 10, 2008 11:58:32 GMT Mark Makin said:

I have to agree with Michael. This argument is similar to the ones you have with people who own classic sportscars. They spend every weekend underneath them but never drive them anywhere.

I have owned over 60 Nationals and certainly many things have been in need of adjustment and repair - but NEVER have I worried about intonation. I think GerryCs comment about pushing it till it meets the note you expect to hear is spot on!!

Lets just enjoy playing the things!

Let's see if I understand what you're saying: if I would like to have a resonatorguitar that intonates right, this automatically makes me one of those people who don't play their guitar?
In that case, I better start to change the bridge until they don't intonate right anymore, becaue I sure want to be one of the good guys!

Regards, John

[Deleted]

Is anyone out there a regular user of Tark's product?
(I don't mean to imply no-one uses it, just be nice to hear another angle on this)

[tark]

Hi Michael,

I'd agree with with you that its perfectly possible to make great music on an imperfect instrument. Also as guitarists we are working with instruments designed for equal temperament, itself a compromise tuning. If good intonation is so easy to achieve and not of much consequence anyway, why do conventional acoustic guitars have compensated bridges and electric guitars have compensation adjustable bridges? The tuning and string behaviour of these other varieties of guitar are in no way different to resonator guitars.

The thread started off on the subject of biscuit bridge single cone guitars. A design which I think I'm right in saying that the Dopyeras apparently had little to do with and one they disowned.