Ukulele intonation – compensating the saddle

I bought a cheap Makala pineapple ukulele secondhand on eBay – I couldn’t justify anything expensive. Overall I’m very happy with it – the tone is fine & it holds its tune. However the intonation (tuning) of the fretted notes was poorer than I’d like particularly on the C (lowest and thickest) string.

There are a number of reasons why this can happen:

  • The nut and/or the saddle is too high, so the string gets stretched when you press your finger down. This raises the pitch.
  • The saddle needs to compensate for the thickness of the string. Thicker strings don’t bend and vibrate in exactly the same way as thinner strings so the length needs to be slightly different.

Adjustable compensated saddles are a standard feature of electric guitars and basses providing screw adjustment of the length of the string. However for some reason they are not standard on acoustic instruments – maybe just because of the weight. Expensive ukuleles have fixed compensated saddles but cheaper ones (and mine is very cheap) don’t.

I checked the action (distance from string to fret) at the first fret and the 12th fret and these appeared to be ok – well within the figures given on the websites I found.

So what I needed to do was move the saddle away from the fretboard for the thickest (C) string. This involved cutting back the saddle until the intonation was correct at the 12th fret. Even on a cheap instrument this is a bit daunting.

To make the process reversible I bought a new saddle. I rubbed it on fine sandpaper until it was the right size to fit into the slot. The old saddle could be slid out once the strings were slackened.

Checking the tuning at the 12th fret

With the new saddle in place I could then tweak the shape until the intonation was correct. The process is:

  1. Mark the saddle with pencil to show where each string lies
  2. Check the string is in tune
  3. Check the tuning at the 12th fret. If the tuning is sharp then the saddle needs to be tweaked a bit more.
  4. Slacken the strings so the saddle with slide sideways a bit
  5. Very cautiously shave the saddle at the pencil marks. I used a gouge – mainly because they are currently sharper than my chisels. With the saddle in the instrument a slip could damage the instrument and/or the strings.
  6. Move the saddle back to the correct location.
  7. Retune the string and repeat from step 3.
  8. Once all strings are correct then ensure all strings are correctly in tune and check again.
My compensated saddle

The process worked fine and the intonation of the instrument is much better. However the tone seems worse – noticably harsher. I’m not sure if this is the material of the new saddle (bone instead of plastic), the shape of the new saddle (it is still a bit square) or if I’m just imagining it.

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