Intonation issues

[LowMoFo]

Greetings, low-enders!

I'm having some issues with intonating a couple of my basses, and I figured I'd find the advice I need here.

i've recently adjusted the neck relief on a fretted 5-string, so now am now needing to re-intonate it.

Fretting at 12, then playing the 1st harmonic, most of the strings are pretty accurate. But in at least one string, as I play the harmonic, the needle wavers, which I wonder is the oscillation of a poorly intonated string. But I've tried, as an experiment, deliberately putting the intonation out on the strings which don't produce that wavering, then re-adjusting so it is intonated correctly.

Tried the same with the rogue strings, and it still wavers. Can anybody tell me why it wavers? Is it a string issue, a tuner issue, or what?

The second issue I have is with an unlined, fretless 4-string. Which begins with the fretting at the 12th.

A movement of just one millimetre when fretting will obviously give a different reading. I've looked on t'interweb, and many people maintain that intonation on a fretless doesn't matter, it's all about the ear. The 'physics' bit of my brain disagrees, but is no expert.

I've also read however, in a book by Leo Lospennato, that intonation can be done using the 1st harmonic and the open string, be it on a fretted or a fretless. This would obviously make intonation easier, as it avoids any fretting inaccuracy, but this book is the only place where Open-string adjustment is mentioned. The guy knows way more than I do, so I just wanted to know what you guys think, as I know less than you fine people...

All the best,

S

[3below]

I have found getting the intonation 'spot' on with my 5 stringer B string has been a compromise.  Bass is a G&L, nice new strings (both TI and Chromes flats tried).  The notes fretted do change pitch slightly from slightly sharp on the initial attack to correct pitch in the 'steady state'.  We are talking cents here.  I also found that the floppiness of the B string results in finger pressure being a factor in tuning.  My compromise was to balance the open B, octave B  and fretted at 3,5th & 7th intonation, based on me mainly using 3,5&7 on B string.

My take as a Physicist is that initial plucking of the string causes the tension to increase significantly , hence increase in frequency (pitch).  As the string amplitude decreases with energy losses the frequency drops. It would be interesting to measure these transient frequency changes (This surely has been done) and how well a string remains tuned over the lifetime of a note.  I have the kit at work and may take a quick look in the near future.

[LowMoFo]

Hi there,

Thanks for your reply, I only fret as hard as I would if I was actually playing, but it's interesting to learn how such a small variation in pressure can still make a difference. I'll have to try the 3/5/7 balancing act, I think, thanks for the suggestion.

As for the wavering, it's about 1 cent either side of '0'. The initial attack obviously shows 'sharp', but as the note 'settles', this is when the wavering shows, and remains as the note decays. (Almost like using harmonics as a tuner on frets 5 & 7 on adjacent strings, before achieving spot-on tuning.)

Deep breath, & back to it... 😀

In the meantime, sir, thanks very much for your advice, definite food for thought, and very much appreciated!

[LowMoFo]

Sorry, I'm a Richard. The wavering info i gave was incorrect.

It wavers between 438 & 442 Hz, which translates to roughly 10 cents either side of 0.

[3below]

Thanks for reply.  I would not worry about intonation errors of a few cents, different finger pressure, hand position, vibrato and temperature will also come into play in a gig. Just to add to the fun, in one musical genre I played in, tuning slightly sharp improved the overall band mix. I have no idea why this should be.

[3below]

5 minutes ago, LowMoFo said:

Sorry, I'm a Richard. The wavering info i gave was incorrect.

It wavers between 438 & 442 Hz, which translates to roughly 10 cents either side of 0.

Is this one string (B would be my suspect) or all of them?

[BassBus]

I would say that intonation matters just as much on fretless as fretted. Chris McIntyre, renowned luthier, advised me to intonate a fretless with something small like a slim allen key. Pick the open string or harmonic then use the allen key directly over the twelfth position and pres it onto the board. That makes it as accurate as possible. Works really well for me.

[paul_c2]

I would say that it doesn't - ie intonation doesn't matter (as much) on a fretless. On a fretted bass, it DOES matter because once you've tuned it, and you play normally, then you have little/no control over the pitch except for what the frets determine for you. Sure, you can bend up a little but it would be a dramatic alteration to technique and difficult to consistently do. On a fretless, the equivalent adjustment would be very easy to do in the moment and not at all unnatural. 

The relative intonation between each of the strings is probably more important than the actual intonation setting. It would need to be quite a bit out, to actually notice when playing.

[LowMoFo]

2 hours ago, 3below said:

Thanks for reply.  I would not worry about intonation errors of a few cents, different finger pressure, hand position, vibrato and temperature will also come into play in a gig. Just to add to the fun, in one musical genre I played in, tuning slightly sharp improved the overall band mix. I have no idea why this should be.

This is very good to know. I'm as mystified as you regarding the sharp tuning affecting the mix, but very glad that it worked out well. Thanks again!

[LowMoFo]

1 hour ago, BassBus said:

I would say that intonation matters just as much on fretless as fretted. Chris McIntyre, renowned luthier, advised me to intonate a fretless with something small like a slim allen key. Pick the open string or harmonic then use the allen key directly over the twelfth position and pres it onto the board. That makes it as accurate as possible. Works really well for me.

Another tip which I just didn't occur to me, definitely worth a try. Thank you too, sir!

[LowMoFo]

59 minutes ago, paul_c2 said:

I would say that it doesn't - ie intonation doesn't matter (as much) on a fretless. On a fretted bass, it DOES matter because once you've tuned it, and you play normally, then you have little/no control over the pitch except for what the frets determine for you. Sure, you can bend up a little but it would be a dramatic alteration to technique and difficult to consistently do. On a fretless, the equivalent adjustment would be very easy to do in the moment and not at all unnatural. 

The relative intonation between each of the strings is probably more important than the actual intonation setting. It would need to be quite a bit out, to actually notice when playing.

Kinda getting the idea from you guys that I should basically just chill about the fretless & get on with playing it.

Thank you guys!!

[fleabag]

Just for the record,  i use open string and then fret that string at the 12th fret, and not the harmonic.

[LowMoFo]

That's interesting to note, so it appears that any of the three points (open, 12th fret, 1st harmonic) can be used. I wonder which method gives greates accuracy, or if the previously mentioned 'balancing act' should be applied as a general 'rule'.

Either way, thanks Fleabag.

[Mottlefeeder]

I have to say that I have never understood the reason for setting intonation at the 12th fret, other than the ease of comparing a fretted octave note with the harmonic octave note.

Apart from fanned fret designs, surely minimising the error at the 1/2 open string length (12th fret) means that you will maximise the error at 1/4 and 3/4 of the open string length, and 1/4 open string length is where I spend most of my time. On that basis would it not be better to set the intonation to by right at about fret 7?

What am I missing?

David

[LowMoFo]

Hi Mottlefeeder,

Regarding your question at the end of your post, it appears you're missing nothing.

Said question got me a-thinking, so I went on a t'interweb search, and it seems lots of low-enders follow exactly that method, and for exactly the reasons you applied in your post.

Many thanks for your help, all, I'm off to learn how NOT to overthink stuff - hopefully...

 

[Chienmortbb]

Setting intonation at the 12th fret allows for very basic tuners. Nowadays tuners are more sophisticated but if still makes sense the inonate at 12.  It is half way between the bridge and nut and assuming all the fret slots are cut  accurately,  setting intonation at fret 12 will be good up and down the fingerboard. What you are trying to do is make sure the length of string from Nut to fret 12 is the same length as fret 12 to bridge. 

[Mottlefeeder]

On 19/06/2019 at 20:03, Chienmortbb said:

Setting intonation at the 12th fret allows for very basic tuners. Nowadays tuners are more sophisticated but if still makes sense the inonate at 12.  It is half way between the bridge and nut and assuming all the fret slots are cut  accurately,  setting intonation at fret 12 will be good up and down the fingerboard. What you are trying to do is make sure the length of string from Nut to fret 12 is the same length as fret 12 to bridge. 

I'm not sure that I agree with that last comment. If you want fret 12 to be the midpoint of the string, then the bridge would be at 90 degrees to the strings, just like the nut.

I think that what we are trying to achieve is to make the vibrating length of the string the same on both sides of fret 12. But, the vibrating length of the string is not the distance between the nut and the bridge, but a slightly shorter distance, governed by the thickness (mass?) of the string. So, even if you position the frets to accomodate these shorter vibrating lengths, they are still going to be a compromise across the string set.  

Which brings me back to my starting point, can you hear the tuning error, and if so, should we be setting the intonation to minimise the error in the part of the fretboard we usually inhabit?

David

[paul_c2]

AIUI its set at the 12th fret simply for convenience, because the harmonic sounds the same octave/note as the fretted note. We could just as easily do it at 19th fret. Or 24th for those who have it.

[Stub Mandrel]

On 30/05/2019 at 21:34, Mottlefeeder said:

I have to say that I have never understood the reason for setting intonation at the 12th fret, other than the ease of comparing a fretted octave note with the harmonic octave note.

Apart from fanned fret designs, surely minimising the error at the 1/2 open string length (12th fret) means that you will maximise the error at 1/4 and 3/4 of the open string length, and 1/4 open string length is where I spend most of my time. On that basis would it not be better to set the intonation to by right at about fret 7?

What am I missing?

David

First, we accept that the even tempered nature of a fretted instrument is a compromise, but if you have the octaves right, then every note in between will sound acceptable.

As @paul_c2 says, if you use a bass/guitar tuner (which uses even temper) you can set the intonation at any fret.

If you do it by ear at a non-octave fret, you may well find some notes sound more out of tune, especially in some keys.

On the mechanics, we need to set the intonation because fretting slightly lengthens the strings and slightly increases the tension. The tension increase dominates making the note sharp. We make the distance from nut to bridge slightly less than twice the distance from twelfth fret to bridge to compensate for this. The effect is more marked with thicker strings, partly because we set them higher and partly because they are, err, thicker and therefore stiffer. So the saddles for thicker strings need to be further away. On a guitar changing from plain to wrapped strings makes them more flexible, which is why you see a staggered line.

Finally, strings are not 100% consistent... so swapping in an 'identical' set of strings amy still require a tweak.

 

 

[Mottlefeeder]

On 21/06/2019 at 22:52, Stub Mandrel said:

First, we accept that the even tempered nature of a fretted instrument is a compromise, but if you have the octaves right, then every note in between will sound acceptable.

As @paul_c2 says, if you use a bass/guitar tuner (which uses even temper) you can set the intonation at any fret.

If you do it by ear at a non-octave fret, you may well find some notes sound more out of tune, especially in some keys.

On the mechanics, we need to set the intonation because fretting slightly lengthens the strings and slightly increases the tension. The tension increase dominates making the note sharp. We make the distance from nut to bridge slightly less than twice the distance from twelfth fret to bridge to compensate for this. The effect is more marked with thicker strings, partly because we set them higher and partly because they are, err, thicker and therefore stiffer. So the saddles for thicker strings need to be further away. On a guitar changing from plain to wrapped strings makes them more flexible, which is why you see a staggered line.

Finally, strings are not 100% consistent... so swapping in an 'identical' set of strings amy still require a tweak.

 

 

Now I'm really confused. If I set the intonation so that fretting at the 12th fret gives the same note as the harmonic at the 12th fret, and the string break angle holds it firmly at the bridge and at the nut, why aren't the two half-string lengths the same?

David

[BassBus]

8 hours ago, Mottlefeeder said:

Now I'm really confused. If I set the intonation so that fretting at the 12th fret gives the same note as the harmonic at the 12th fret, and the string break angle holds it firmly at the bridge and at the nut, why aren't the two half-string lengths the same?

David

The string length between the nut and the twelfth fret is fixed but you are moving the saddle backwards and forwards to set the intonation so that changes the length between the twelfth fret and the bridge saddle.

[Stub Mandrel]

Get out a tape measure, it will all be clearer.

As @BassBus says the 12 fret is fixed. For a 34" bass it's 17 inches from the nut. Typically the saddle for the E string will be somewhere around 34 1/2" from the nut.

(The first harmonic's node will be at 17 1/4" rather than 17", but we don't notice that.)

When fretted at the 12th fret the free length is 17 1/2" . That extra 1/4" of free length lowers the pitch of the string by enough to compensate for the increased tension when fretting.

To prove the effect, just fret the E-string at the 12th fret, pluck it and bend slightly,  by the same as the action, say about 1/8" to 3/16" (or 1/4" if you are Carol King!)

The change in pitch you here is pretty much the amount the saddle displacement has to compensate for.  It will probably be rather more than half a semitone on the E string.

Bend the G string by an amount equal to its action. the pitch change will be a lot smaller, which is why the saddle movement is less.

[Mottlefeeder]

6 hours ago, Stub Mandrel said:

Get out a tape measure, it will all be clearer.

As @BassBus says the 12 fret is fixed. For a 34" bass it's 17 inches from the nut. Typically the saddle for the E string will be somewhere around 34 1/2" from the nut.

(The first harmonic's node will be at 17 1/4" rather than 17", but we don't notice that.)

When fretted at the 12th fret the free length is 17 1/2" . That extra 1/4" of free length lowers the pitch of the string by enough to compensate for the increased tension when fretting.

To prove the effect, just fret the E-string at the 12th fret, pluck it and bend slightly,  by the same as the action, say about 1/8" to 3/16" (or 1/4" if you are Carol King!)

The change in pitch you here is pretty much the amount the saddle displacement has to compensate for.  It will probably be rather more than half a semitone on the E string.

Bend the G string by an amount equal to its action. the pitch change will be a lot smaller, which is why the saddle movement is less.

OK, I see where I'm going wrong - I assumed that getting a harmonic at the 12 fret by damping the string there meant that the node was at the 12th fret. From what you have said, the node is not there, but is close enough that damping the string at that point will produce the harmonic. The rest of it now makes more sense.

Thanks

David