Hofner Violin Bass - out of pitch

[squeez0r]

The strings are all in tune at the open fret and also at the 12th harmonic.  But it's out of tune at the 12th fret. 
I was  going to adjust the truss rod to reduce the relief, to lower the pitch at the 12th fret, but the pitch is not the same across all strings at the 12th fret: 
E is -8 cents
A is +4 cents
D is +11 cents
G is +19 cents
Will a truss rod adjustment be enough or is there something else wrong with it?  Is the neck twisted?

Thanks for your help.

[Maude]

Don't these have a floating bridge? I'd bet the bridge is just slightly in the wrong place. 

[James Nada]

You need to adjust the intonation. 

[Woodinblack]

Harmonics will always be correct if the fundamental is correct, their only use in tuning is to compare to the 12th (or 17th) fret. Changing the truss rod will never make (any appreciable) difference to intonation, although if you are going to do it, do it first.

It is all about the bridge.

Play a harmonic at the 19th fret, then play the note at the 19th fret.

if the note is sharper than the harmonic, ie, the note is higher, it means that the string is shorter than it needs to be, so move the bridge end back away from the neck. if it is lower, then the string is longer than it needs to be, so move the bridge end forwards (towards the neck).

I don't know how the hofner does it but if it is a floating bridge then you just have to come up with a best compromise.

[Happy Jack]

12 hours ago, squeez0r said:

The strings are all in tune at the open fret and also at the 12th harmonic.  But it's out of tune at the 12th fret. 
I was  going to adjust the truss rod to reduce the relief, to lower the pitch at the 12th fret, but the pitch is not the same across all strings at the 12th fret: 
E is -8 cents
A is +4 cents
D is +11 cents
G is +19 cents
Will a truss rod adjustment be enough or is there something else wrong with it?  Is the neck twisted?

Thanks for your help.

Simple answer - take the bass to a luthier for a set up.

Complicated answer - this could be either a trussrod problem or a bridge problem.

Trussrod problem

If the neck has too great a curve to it, then the action will be too high. If you have to push the strings down by nearly half an inch at the 12th fret then you're bending the strings which will make them sound sharp.

If this is the problem, then you need to tighted the trussrod. Do this a quarter-turn at a time, checking the string height after each and every quarter-turn ... softly softly catchee monkey.

Bridge problem

Judging by your measurements, looks like you have very nearly a straight line going there. If there isn't a problem with the trussrod, that tells you that the bridge has been correctly intonated, but has since moved or been knocked.

Have you recently changed the strings, perhaps? Or has the bass been dropped or kicked by accident?

Whatever. What you now need to do is to tap the bridge, gently but firmly, on the G side (because the G side is the furthest out of true). You're trying to get the bridge straighter. I recommend using the spine of a fairly heavy paperback book for this.

After a few taps, if the intonation is getting worse, then you're tapping in the wrong direction ... tap from the other side.

If tapping won't move the bridge, slacken off the strings slightly and try again.

If tapping with slightly slackened strings still won't move the bridge, then someone has fixed the bridge with double-sided tape, and quite possibly in the wrong position.

In that case, take the bass to a luthier for a set up.

[Stub Mandrel]

You might not find that getting the right angle and position of the bridge with the default saddle arrangement gives you the best compromise (all strings within a few cents of spot on).

Adjust it to get the best possible result, and if one or two strings are still significantly out, consider changing the slot their saddles are in.

You MIGHT find that (depending on the strings you use) the best setup is with the E saddle in slot 3, A and D string saddles in the slot 2 and the G string in slot 1. You may even find another arrangement works best like this one:

Personally I would angle the bridge to get the best 

 

Edited March 2, 2020 by Stub Mandrel

[hooky_lowdown]

Violin basses are well known for not being able to get perfect intonation, mainly due to the floating bridge.

[James Nada]

I've found that I get the best results with my Hofner Club putting the bridge saddles in a straight line and angling the bridge.  Here's a pic...

 

(I'm sure different string sets will make a difference to the best way of setting the bridge so, for the record, mine are La Bella 760FHB2)

[grandad]

I've had a few violin basses over the years and have managed to setup some reasonably well but never perfect.

I eventually settled down to owning a HCT and had that setup by a luthier. That isn't perfect but it's near enough.

They are a hell of a fiddle.

[linear]

16 minutes ago, grandad said:

They are a hell of a fiddle.

[police squad]

yep the bridge moves about if you lean on it too much.

I had mine pinned because i rest my hand on it when I play and it used to move.

now it's fine

[squeez0r]

FIXED 😀

Thanks for your help guys.  It was just the bridge after all. 

When I got the bass new a couple of months ago, I noticed that the floating bridge was set at an angle, so I was very careful when I removed the foam transport pad to position it in the same place again; but it was obviously set wrong at the factory, hence the pitch problem that I only noticed when I started playing bass lines higher up the neck.

I corrected the problem by getting the G string in pitch first, then the E string, and finally the A and D strings.  After a bit of wiggling about I finally got the bridge lined up straight with the pickup and in tune across all strings (with just +/- 7 cents between them).  Happy days.

Hofner Violin Bass - Intonation
Tools
• Guitar/bass tuner
• Snipe-nose pliers
• Tape measure

1. Measure and Slide
• Measure the distance from the fretboard side of the nut to the middle of the 12th fret
• Measure the distance from the middle of the 12th fret to the middle of the bridge saddle insert under the G string
• These distances should be the same; if not, loosen the strings and gently slide the bridge to the correct distance
2. Tune
• Tune each string to standard pitch.
3. Adjust Height
• Adjust the string height (action) as desired for comfortable playing by turning the knurled thumbwheels on each side of the bridge carefully with the pliers
• The height should be set so the strings do not buzz or rattle when playing in low or high positions on the fretboard
4. Intonate
• Lightly touch the G string at the 12th fret and pluck with the pick to sound the harmonic tone. It should indicate correct pitch; if not, continue sounding the harmonic tone while tuning the string until it’s tuned to the correct pitch
• Fret the G string firmly at the 12th fret:
o if the fretted note shows sharp (higher) on the tuner, loosen the strings and slide the bridge back about 3 mm
o If the fretted note shows flat (lower) on the tuner, loosen the strings and slide the bridge towards the neck about 3 mm
o Retune the strings and repeat the above steps until the fretted note is at the correct pitch
• Repeat the above steps on the E string to set the other side of the bridge for proper intonation
• All the strings should now be intonated
 

It does have a bit more relief in the neck than my other bass guitar, but I can live with that as I've lowered the action and filed down a single sharp fret that was causing fret buzz. It's very playable, even at the dusty end now.

Thanks again.

 

[markdavid]

Glad you got it sorted, also worth remembering in case you get another of these or similar in the future, the saddles can be taken out and re positioned for fine tuning of the intonation