Double Bass Intonation questions

[ProfChris]

My recently acquired bass came with synthetic gut strings, which are probably 20 years old but haven't been played much in the last 15 years. The D and G sing out nicely, the A is rather muted and the E is just a thud really.

I've bought some cheap Chinese strings (wire core, steel tape wound) to experiment with, and these restore life to the A and E (though quite a different tone). However, they intonate differently from synthetic gut - a '3rd fret' note on the steels is nearly 1/2 inch nearer the bridge than on the synthetic guts. I expected a difference because of the string diameters, but not this much!

I'm happy with the sound and playability of synthetic gut D and G, so want to end up with a mixed set which gets all four strings in better balance, both tone and intonation.

Questions:

1. Might the synthetic gut have stiffened with age? Would new D and G strings reduce the difference? If so I should do that first, and might find I like the E and A from a new set.

2. Would synthetic core but metal tape wound strings intonate closer to synthetic guts? My guess is yes, as they're less dense than steel core, but if anyone knows ...

3. I suspect I'll end up with synthetic gut D and G, and synthetic core/metal wound E and A. I seem to have some choice of metal windings, copper or steel. Any suggestions?

I'm playing simple stuff at open mics and pub gigs - pizzicato, roots and fifths, a few walkups etc. Nothing beyond the neck joint! But I'm having lots of fun with it.

 

[jj.833]

I don't think the intonation of strings is dependent on the core or the winding. You tune the string, and then divide it using your finger into right semitones.

However, the state of the string may affect the tuning or distribution of partials. Old strings on bass guitar can sound weirdly out of tune even without another tone to compare to - that's because the winding gets worn from the fret side only, forcing the string to vibrate unevenly. I never heard such a thing on double bass though.

It's hard to say anything on 20yo unknown strings, or about new unknown cheap Chinese strings. I have 15yo Obligatos on one bass, and they - after some 10 years of hiatus - sound great.

Suggestion: buy used or try to borrow good bass strigns, and try whether the tuning gets better. If not, take your bass to a luthier for a setup, as the intonation problems may originate in bad nut or bad bridge.

 

[ProfChris]

I've built around 50 fretted instruments, so I know part of the answer - thicker strings (D and G on my setup) are stiffer near the nut, which affects the intonation near the nut. At the octave, all mine are pretty much at the same point. What I didn't know was whether synthetic gut stiffens with age - the strings sound good, but I'm new to DB strings.

Any advice on my E and A? The cheap metals are just to hear the broad tonal differences, and also because I'm lowering the bridge (actually installing a new, lower one) and thought the synthetic E and A wouldn't respond well.

I know I want synthetic D and G - what pairs well for E and A?

 

[Francois Blais]

What's the height of the strings above the fingerboard at the end of the fingerboard?
Regarding the grooves at the nut, is it just deep enough to fit one or two business cards between the strings and fingerboard?
Higher than that makes the strings heavier to press, and affect the intonation.

 

[ProfChris]

Fine at the nut, silly high (20mm for the E!) at fretboard end. Thus the new bridge.

But that would affect all strings equally (or even more for the E than the G), so it's definitely to do with the differential stiffness of the string pairs. I wondered if this is normal for m7xed strings sets, or whether my synthetics need replacing.

 

[Co.]

Different core materials stretch differently. With the action that high, it might be possible, that the stretching of the string, when pressing down, causes the difference in intonation.

 

[Don Hergert]

...

Questions:

1. Might the synthetic gut have stiffened with age? Would new D and G strings reduce the difference? If so I should do that first, and might find I like the E and A from a new set.

2. Would synthetic core but metal tape wound strings intonate closer to synthetic guts? My guess is yes, as they're less dense than steel core, but if anyone knows ...

3. I suspect I'll end up with synthetic gut D and G, and synthetic core/metal wound E and A. I seem to have some choice of metal windings, copper or steel. Any suggestions?

I'm playing simple stuff at open mics and pub gigs - pizzicato, roots and fifths, a few walkups etc. Nothing beyond the neck joint! But I'm having lots of fun with it.

I can probably answer or partially answer some of these. It sounds like your synthetic gut strings may have been weed-wacker or gator-line (thick monofilament nylon based strings), which at least on some double basses tend to acoustically sound really pretty good for the D and G, and really thuddy on the E and A. If you like the general tone and thick feel of the synthetic gut D and G, there are other synthetic strings -- pricier synthetic core and synthetic wound strings -- that actually do a decent job for the E and A strings.

I'm using (gator-line based) Superior BassWorks Deluxe "Dirty Guts" D and G over Innovation SilverSlaps E and A. I found the same thing as you with the "Dirty Guts", acoustically the E and A were too low volume and unclear (although they were excellent amplified) while the D and G are really quite good. So that's why I swapped in the SilverSlaps E and A.

In my experience weed-wacker and gator-line strings can tend to get less flexible over time, but all double bass strings age due to tension related stretching, so that may simply be a result of being under tension. They do tend to last a long time.

Stiffness is a double bass string quality that a person gets used to, but it can easily be accentuated by unnecessarily high action. I've recently adjusted my end-of-fingerboard action at about 6mm-E to 5mm-G and the instrument plays like silk; 20mm is at least about twice as high as fat synthetic or true gut double bass strings should be, and it's even worse for thinner metal strings -- that high action by itself will contribute to intonation difficulties. (I'm honestly left wondering about the condition of your neck's heel joint.)

Many of your other questions have been answered well... Even if your setup is right, intonation is still mostly in your ears and hands; intonation on the double bass is a constant learning process. But if your bridge is set wrong, or if other things are going on, you may also be fighting those issues. An in-person visit to a double bass specialist for a checkup might be an excellent idea.

As far as strings for double bass in general are concerned, I'd highly recommend spending some time reading the string descriptions and explanations at Gollihur Music's string website; Gollihur Music is extremely well regarded in this community for all that they do (NFI).

 

[ProfChris]

Thank you @dhergert that's very enlightening.

The neck joint is solid, but the previous owner played vigorous slap bass on it for 30+ years - the fretboard wear is quite impressive! I guess he liked really high action. I plan to take it down to 10/8mm to begin with, and adjust from there once I get a feel for what works for me and the instrument. Bridge is set right, though the feet need fitting better. I can sort that easily.

I'll check out the SilverSlaps. I'm tempted by Aquila Red Springs, copper over synthetic, if anyone has experience of those.

 

[Don Hergert]

I've tried Aquila Sugar Slaps and loved them, however they did not like my custom tailpiece so I had to retire them. I can recommend Aquila in general for their strings and excellent service.

 

[ProfChris]

I've lowered the action to around 10mm, and now have steel E and A, with real gut D and G. The intonation problem has gone.

Surprisingly, the cheap Chinese strings at £30, $35US, sound and play really quite nicely. They work well with the guts too.