School Me on...Why a New Bass Goes Sharp

[Killing Floor]

Maybe because the world is flat?

 

[Koog]

Wood and metal expand and contract with humidity and temperature changes.

 

[Gravedigger Dav]

Definitely a temperature issue, wood expands and contrats.

So do strings.

 

[bigdaddybass12]

Usually a new bass neck will wander around a little. It will settle down. I usually buy used basses because the neck would have freaked out after a couple years.

 

[DanDBassist]

A dozen years ago, I played a casual gig at my boss' house in Newport Beach, CA harbor on his back deck. I swear, I WATCHED the neck of my G&L SB-2 bow and the bass go sharp when the evening beach fog rolled in. Made note of THAT life lesson!!!

The most sensitive BG owned by me was a 1983 Fender Elite. In 1993 we drove from an altitude of 6500' to 3600'. The neck had bowed so much it was unplayable. This is when it's very helpful to have your truss rod tool and know how to use it.

 

[Lowbrow]

Warming temperatures would cause the strings to contract slightly resulting in sharp tuning.

 

[Spectre Gunner]

I'll throw this in - I would wager that when you tune, you bring a string in tune from the 'bottom up' (starting flat and arriving in tune). That's how most of us are taught to tune. Depending on how tight your nut fitment is, sometimes the string tension from the tuner to the nut is higher than the speaking legnth of the string from 'tuning up'. The tension slowly levels out to the speaking side, throwing you a few cents sharp. This is, of course, in conjunction with humidity, ambient temp, wood & string temp, and accidentally bumping the tuners.

This is what I’ve been taught as well. But I was also taught that the opposite applies to a headless bass. For example, on my Kubicki Ex-Factor I’m supposed to go sharp and then bring it into tune. Not sure why that is but I suspect it has something to do with the ball end of the strings being at the headstock rather than at the bridge.

 

[iiipopes]

When new, I notice that they slip “sharp” after I’ve tuned them “up to pitch”. Even with my Mike Lulls, even though Mike told me a long time ago that they make the nuts to accommodate a set of 50s, 70s, 85s, 105s, and 135s.

When you tune and the nut slots don't have the proper geometry to accommodate the strings, including good witness points and ramps back directly to the tuner, then the strings can hang. And round wounds by definition can hang even with good nut slots. This causes more tension in the leaders between the nut and the tuner than the speaking length of the strings generally, and when this finally equalizes over time, it is like water seeking its own level, and the increased tension in the leader as it equalizes pulls the rest of the string slightly sharp. It's usually not as common at the bridge, due to most bridges having a more rounded and/or wider notch in the nut saddles, but it can happen there as well. Archtop guitar players and others where there is a long back length from the bridge to the tailpiece also observe this issue.

When tuned almost to pitch, say, when still 3-4 cents flat, slightly lift the string and gently tug on it to make sure tension is equalized over the nut slots and bridge saddles, as well as the string itself, and then finish tuning. Also, with a new string, after it is tuned to pitch and the excess tension is relieved from the strings, nut slots, and bridge saddles, make sure to set a good witness point on the strings over both the nut slots and the bridge saddles to help stabilize the tuning.

 

[TrevorG]

All my basses sharpen if you leave them in a draft never mind cold room!!

 

[dougjwray]

Well...
I have a Squier Affinity Jazz which I bought for $45 at a pawnshop in 1991. It never goes sharp or flat. In fact, it has never changed since that first time I tuned it, when I brought it home! This includes gigs in Death Valley and on the peak of Mount Everest!

 

[JW56789]

I appreciate the answers fellas.

This has puzzled me, as among the herd over the years, it occurred on a super-stiff Alembic neckthrough that otherwise was as stable as an observatory clock set-up wise, built in '86, and one of my Squiers, with a far less considered construction and much less aged wood construction, and of course a screw-on neck and a conventional nut instead of brass.

Tuning is bring a given string to a certain lbs./ft. value, and then maintaining it. Both these axes were/are otherwise very stable while playing. And to be precise, the drift sharp is only around 5-10 cents on the BOSS tuner. So the idea of some 'give' in the nut slots, the string equalizing before/after the nut, or excess slack in the keys topping out were always my ideas, but it was just strange to see it over the range of basses I've owned over time, I'd say maybe a third of them exhibited this.

Thanks for the clues !

 

[vindibona1]

This makes me want to giggle. As others have stated, most likely environmental variations. How is the instrument stored when not in use?

In my case, I'll be perfectly in tune when I leave home for a gig. During the setup some of my basses have to be retuned two or three times because of the different environment. Some basses even need a relief adjustment on site because the change is so severe. And at the gig (about 2 hrs) I might check tuning 5-10 times if I want to be precise. Small tweaks after major retuning are frequent. Tuning variations over days should be more than expected.

 

[dougjwray]

My previous post was a lame attempt at humor; but, all kidding aside, I have had the experience of taking a bass out of its case weeks after I last used it, and finding that it's still perfectly in tune. I'm sure I'm not the only one. Stable temperature and humidity, no doubt.