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View Full Version : New Experiment: The Compensated Saddle on an Angled Bridge Slot



sequoia
01-20-2018, 06:18 PM
(Yet another thread on compensation. Sorry.)

As an experiment, I purchased an angled slotted bubinga bridge from Hana Lima 'la supply out of Hawaii. Here is what I got:

106072

As I understand it, an angled slot like this will only work on an ukulele that is strung non re-entrant as opposed to the standard re-entrant tuning that is usual on ukuleles. In simpler terms, the non re-entrant tuning uses a low G string tuning rather than the standard high G tuning. The string diameter in the low G tuning is more like a guitar in that the 4th string (G) is thickest and then each succeeding string gets thinner and thinner until the 1 string is thinnest. This bridge would not work on a high G strung uke.

Anyway, my initial impression is that the angle of compensation is more than would be necessary for a tenor uke. That is a pretty radical angle but I am going to try it just to see what happens. As for the bridge itself, the price was cheap and the quality is OK except for the godawfulbad tool marks on the wings that I have mostly sanded out in the picture but you can still see them and it needs more work.

https://hanalimastore.com/products/bridge-pre-cut-bubinga-fan-braced

Uke Don
01-21-2018, 06:37 AM
You might want to take a look at this on-line bridge compensation calculator. It has a selection of instruments, including ukulele. You can choose the result from individually compensated strings as well as an angled saddle. http://www.liutaiomottola.com/formulae/compensation.htm

anthonyg
01-21-2018, 08:30 AM
Give it a go if you will yet a Linear strung, classic string ukulele will need 1-2 mm of slant from treble to bass at the most. The intonation will be awful.

sequoia
01-21-2018, 06:10 PM
You might want to take a look at this on-line bridge compensation calculator. It has a selection of instruments, including ukulele. You can choose the result from individually compensated strings as well as an angled saddle. http://www.liutaiomottola.com/formulae/compensation.htm

Very interesting, but the calculator was beyond me. Perhaps you could give me the angle for a low string G tenor uke? I couldn't get it to work.

Timbuck
01-21-2018, 10:36 PM
Her's a pic of an Ebony compensated tenor bridge I made 8 years ago I made this one the hard way on the Milling machine....but later i made a batch on the CNC machine...It turned out to be very good on the intonation both low and high G..I got the measurments for the compensation from the David Hurd Website...The angle of the slot is approx: 0 - 3mm.........here's a testing video of the low G compensation https://www.youtube.com/watch?v=lhCwhPKEQcE
You have to remember that the E string compensation is set back at approx: 2mm to start with, so the compensation for the low G at 3mm further back is at 5mm... I hope this helps.:)
https://farm5.staticflickr.com/4607/24961977227_48d3bf978f.jpg (https://flic.kr/p/E2NEaH)bridge 1 (https://flic.kr/p/E2NEaH) by Ken Timms (https://www.flickr.com/photos/150702140@N02/), on Flickr

The device it's resting on is a simple jig I made to drill the string holes at an angle.

jhnmdahl
01-22-2018, 09:37 AM
Here's the standard/re-entrant result table (with length to be added to bridge in inches) :
String# Compensation Straight Saddle Compensation
1 0.0482 0.0631
2 0.0733
3 0.1128
4 0.056 0.082

For low G, 4th string is .04, and straight saddle is .066 to .071

The same guy who runs the calculator suggests that people can't reliably hear the difference between individually-compensated strings and a straight, angled bridge, so provides first and fourth string measurements for a best-fit straight angled bridge as well.

John

Beau Hannam Ukuleles
01-22-2018, 10:25 AM
I get good intonation (within 5 cents) with a 1/8" saddle over all strings.

Uke Don
01-22-2018, 11:37 AM
Very interesting, but the calculator was beyond me. Perhaps you could give me the angle for a low string G tenor uke? I couldn't get it to work.

Here you go. To get a calculation for low G is not exactly user friendly. You can see how close the compensation is for low G using an angled saddle. At about a 10th of a millimeter difference left to right I'd say it's not worth bothering. Low G and Standard Reentrant aren't a lot different from a straight saddle. It might make some difference if you individually compensating the strings.

Low G:
106117

Standard Reentrant:
106123

sequoia
01-22-2018, 06:33 PM
Thanks all for the specs... I measure the angle of compensation on this bridge slot to be exactly 3 mm which is exactly 1/8 inch or 0.125 inches. That is a 3 mm difference between the 1st string and the 4th. Keep in mind that this is in addition to a compensation of 3/32 of an inch (0.094 or 2.4mm) to the center of the saddle on a hypothetical 17 inch scale length which will further set back the angled saddle and increase the compensation. I'm not doing that math as my head is starting to hurt.

If this doesn't make your head swim a little bit, you are a better person than I Gunga Din... What gives me pause is that the calculator from Uke Don seems to call for less an angle. My gut feeling is that the angle of compensation is too much on this bridge slot cut, but when it comes to physics and math the gut don't matter that much. Math don't lie. Perhaps the real problem comes down to removing the bridge if it isn't right. I've removed a couple or three bridges and it was not a fun operation. Really hard to not damage the top to say nothing of a fried finish.