Action/String query

[gt4ever]

So I had my first bass related issue at a gig at the weekend.  I was using my trusty Modulus FU4 with relatively new (8 hours use maybe) Rotosound 66 swing strings 45-105.  About 6 songs in my A string became very thin and didn't resonate much.  It got progressively worse throughout the gig and by the end the string was sitting on the frets when first 3 frets were played but the further up the neck the better note I could get.  I had to improvise and use the E string instead.

The next day I inspected the bass further.  It played absolutely fine and action was playable down the whole string with no issues??  The saddles seemed secure and hadn't moved, I inspected the nut with a magnifying glass to see if there was a hairline, nothing.  There shouldn't be any issues with the neck as its carbon, I've never touched the truss.  I have 2 gigs this weekend and cannot have a repeat.  Any ideas what the problem could have been, has anyone experienced anything like this?? 

 

cheers in advance

 

Rich

[Grimalkin]

How much relief does the neck have and does your string to string setup follow the radius curvature of the fretboard. Is the A string set too low? Also consider the temperature effects on the instrument. 

[gt4ever]

5 minutes ago, Grimalkin said:

How much relief does the neck have and does your string to string setup follow the radius curvature of the fretboard. Is the A string set too low? Also consider the temperature effects on the instrument. 

the neck follows the contour and neck is straight. All strings sit with even gaps.  Saddles all set correct and have not moved.  It’s weird that the day after the gig the A string plays fine with clearance but at the gig I couldn’t get a note from the first 5 frets at all.  I assumed that temps wouldn’t affect a carbon neck.  It was an indoor gig and bass is always kept indoors at ambient temps.

[Aidan63]

So it sounded fine through the amp the next day ? Or was that just playing the instrument acoustically ?

 

 

[gt4ever]

Just now, Aidan63 said:

So it sounded fine through the amp the next day ? Or was that just playing the instrument acoustically ?

 

 

It played fine through the amp the next day.  At the gig, the string was just flat against the frets up to the third or fourth fret, so couldn’t play any note.  I’ve put a metal rule to the frets to see if one had raised but but they’re fine.  I’m really confused 

[Grimalkin]

6 minutes ago, gt4ever said:

the neck follows the contour and neck is straight. All strings sit with even gaps.  Saddles all set correct and have not moved.  It’s weird that the day after the gig the A string plays fine with clearance but at the gig I couldn’t get a note from the first 5 frets at all.  I assumed that temps wouldn’t affect a carbon neck.  It was an indoor gig and bass is always kept indoors at ambient temps.

 

The neck shouldn't be dead straight really. When you pluck a string it has a wider vibration pattern in the middle than at the ends, that's why a slight bow of about a millimetre or more depending, is put into the neck as relief, to allow for the wider vibration at the centre of the string. What leads me to think of temp difference is that you found the bass ok the next day. So what changed...

[PaulThePlug]

1st thing and cheapest option... change the strings.

[Grimalkin]

I was wondering what effect temp would have on carbon fibre too, but this is what it does apparently:

 

"Carbon fiber is a fantastic material with a variety of applications. However, one potential downside of carbon fiber is its negative coefficient of thermal expansion. This property means that when the material is heated, it will actually shrink. This property can be problematic in certain applications where temperature changes are expected."

 

https://www.tencom.com/blog/understanding-carbon-fiber-thermal-properties

[gt4ever]

3 minutes ago, PaulThePlug said:

1st thing and cheapest option... change the strings.

Yeah think that’s a sensible shout.

[Grimalkin]

I don't think it's a string thing at all personally, it's to do with the setup.

[gt4ever]

22 minutes ago, Grimalkin said:

I was wondering what effect temp would have on carbon fibre too, but this is what it does apparently:

 

"Carbon fiber is a fantastic material with a variety of applications. However, one potential downside of carbon fiber is its negative coefficient of thermal expansion. This property means that when the material is heated, it will actually shrink. This property can be problematic in certain applications where temperature changes are expected."

 

https://www.tencom.com/blog/understanding-carbon-fiber-thermal-properties

😯 I didn’t realise that. But if it was the neck would it affect all strings and not just one of them?

[Grimalkin]

1 minute ago, gt4ever said:

😯 I didn’t realise that. But if it was the neck would it affect all strings and not just one of them?

 

Thicker strings have a wider vibration pattern, when you are talking fractions of a millimetre it could be that the A is slightly lower.

 

Fret the first fret on the E string (F) then with the elbow of your right arm rest it on the very last fret of the E string, then with your index of your right hand, feel the gap between the string and the fretboard around the ninth fret, there should be a gap, ideally of around a millimetre +/-. If the neck is too flat, there isn't enough clearance. A slight movement due to temp will be noticeable.

[gt4ever]

58 minutes ago, Grimalkin said:

 

Thicker strings have a wider vibration pattern, when you are talking fractions of a millimetre it could be that the A is slightly lower.

 

Fret the first fret on the E string (F) then with the elbow of your right arm rest it on the very last fret of the E string, then with your index of your right hand, feel the gap between the string and the fretboard around the ninth fret, there should be a gap, ideally of around a millimetre +/-. If the neck is too flat, there isn't enough clearance. A slight movement due to temp will be noticeable.

yep slightest of gaps about a mm

[gt4ever]

1 hour ago, Grimalkin said:

I don't think it's a string thing at all personally, it's to do with the setup.

I’ve had the bass about 4 years now and never had a problem. Have gigged it most weekends over that period too.

[Grimalkin]

13 minutes ago, gt4ever said:

I’ve had the bass about 4 years now and never had a problem. Have gigged it most weekends over that period too.

 

That's probably why it needs a setup. Things change.

[2pods]

String slippage, or unwinding ?

Have had similar years ago. Turned out to be a damaged string.

[acidbass]

In my experience of Roto RS66s, 8 hours playtime is more than enough to wear out a string.

[chris_b]

Just stop taking the drugs.