strings slowly sharpening to correct pitch?

goodweather · #1 06-03-2007, 02:58 AM

Hi everyone

I am wondering whether anyone has seen this before. My bass plays fine after an initial setup (slightly loosened truss rod, adjusted action and set intonation), yet I have noticed the following:

When connected to the tuner, each string initially plays the note very flat and then it moves (sharpens) into pitch. This seems to happen with all 5 strings. If I just tune them sharper, then the same happens, but just "sharpened": the string will initially play in pitch, but then just ends up "settling" at a point which is too sharp.

Has anyone seen this before? When tuning the other bass I have used (with the same tuner), upon hitting a string the (electronic) pointer in the tuner would pretty much jump straight to a position, stay there for a while and then quickly "flatten out".

Any advice on how to fix this? Is this a problem with the bass? Strings? My bad?

Thanks!

M

pkr2 · #2 06-03-2007, 05:38 AM

First, try a fresh battery in the tuner. Tune so that the centering led comes on briefly and then goes flat. Always tune on the attack portion of the note.

Sometimes it's easier to tune the 12th fret harmonic.

It's not your bass. It's a characteristic of inexpensive tuners.

ddnidd1 · #3 06-03-2007, 11:17 AM

Strings that are not relatively new can do strange things due to corrosion and wear from contact with the frets.

goodweather · #4 06-04-2007, 12:20 AM

Hi guys -

Thanks for your help. I put a fresh battery in the tuner (also tried using my Korg Pandora's built-in tuner) and it still happens. This didn't happen with my previous bass. I've also noticed that this happens mostly with the B string; with the other four ones it is hardly noticeable.

Is replacing the strings the way to go?

Thanks ! M

pkr2 · #5 06-04-2007, 04:19 AM

Quote:

Originally Posted by goodweather

Hi guys -

Thanks for your help. I put a fresh battery in the tuner (also tried using my Korg Pandora's built-in tuner) and it still happens. This didn't happen with my previous bass. I've also noticed that this happens mostly with the B string; with the other four ones it is hardly noticeable.

Is replacing the strings the way to go?

Thanks ! M

If it does it with both tuners, it sure does sound like a problem with the bass. As was mentioned, strings gone bad can cause some strange problems, but it's pretty unusual for a string to actually go up in pitch when it goes out of tune.

If the problem is with the bass, the string(s) are the most likely suspect.

Good luck.

202dy · #6 06-04-2007, 06:23 AM

It depends on the time period that is being considered and the amount of force being applied to the string. If this activity is occurring over a period of less than a second then it is more or less normal. It also takes a short period of time for the energy to fully express itself in the string. Hence it is initially flat for a few microseconds. When the string is plucked it is stretched the same as the tuners do. Once the string is expressing the full amount of energy it does so at a higher pitch since the string is now "tuned" a bit sharp. This also has a short duration, sometimes a bit longer the "flat" stage. Then the string settles at its normal pitch for a long period. Eventually it loses energy and will start to go flat before it stops vibrating altogether and returns to silence. This phenomenon is expressed in the concept of ADSR. That is Attack, Delay, Sustain, and Release. The curve rises and peaks at the attack and drops slightly during the delay phase. Those are perceived by the tuner as sharp then flat. It settles during the sustain portion of the curve which is relatively flat. The release shows up on the curve as a slope to right as the string loses energy. ADSR is usually employed with synthesizers and allows the instruments to sound musical. Here is an image of the graph:

Jim Carr · #7 06-04-2007, 02:43 PM

This type of thing is common on upright.

It may sound obvious, but I advise using your own sense of pitch discrimination. Tune it by ear and see if your machine agrees.

In any case, I'd change strings (use a good quality set), break them in, and restest with your tuners.

Some tuners let you set the "quickness" of response. I find the Pandora tuner has too fast a response, so I tune to the steady state of the pitch (the sustain in the ADSR model), when using it. My prefered tuner is a Korg Orchestral Tuner (OT). It has an adjustable response time and a lot of nice features.

If you can't hear the difference, but your tuner does, consider getting one which has an adjustable response time. However, it is much more important to just find a good strategy that puts your bass in tune. Experiment and let us know what happens.

ps Force on the strings can make a big difference.

Sadowsky · #8 06-06-2007, 01:08 PM

I will guess your strings are binding in the nut slots. There is residual tension between the gear and the nut. This is more common on angled headstocks than Fender style.

Roger

202dy · #9 06-07-2007, 12:57 PM

Quote:

Originally Posted by Sadowsky

I will guess your strings are binding in the nut slots. There is residual tension between the gear and the nut. This is more common on angled headstocks than Fender style.

Roger

This is the chief reason that tremolo tailpieces do not return to pitch. It is sometimes refered to as slack storage. Hence the locking nut in a double locking system. I was not aware that it could cause tuning problems on a bass. Please elaborate.