The Acoustic Guitar Forum

Go Back   The Acoustic Guitar Forum > General Acoustic Guitar and Amplification Discussion > Build and Repair

Reply
 
Thread Tools
  #1  
Old 11-20-2013, 10:42 PM
Monk of Funk Monk of Funk is offline
Registered User
 
Join Date: Jan 2013
Posts: 962
Default Pickup not loud enough on higher strings

I have a guitar that's not of amazing quality just something I can take wherever without worrying about it too much. So, I don't mind doing things to it myself, and kind of prefer that to get to know it a little. The issue I have with it, is that the higher strings aren't loud enough through the pickup.

It came what I presume were light strings, but I've fitted medium strings to it. Not sure if that's part of the issue or not. But, I'd like to keep the medium strings on there and somehow adjust it so that the pickup comes in louder through the higher strings. It's basically the non wound strings that are too quiet, and it kind of gets worse the higher the strings are.

Is there something I can do to get the pickup coming in louder in the higher strings?
Reply With Quote
  #2  
Old 11-21-2013, 12:13 AM
simply rod simply rod is offline
Registered User
 
Join Date: Jun 2013
Location: Japan
Posts: 226
Default

I presume it's an acoustic? What kind of pickup is it?
Reply With Quote
  #3  
Old 11-21-2013, 04:06 AM
Monk of Funk Monk of Funk is offline
Registered User
 
Join Date: Jan 2013
Posts: 962
Default

It is. A fishman bridge pickup.
Reply With Quote
  #4  
Old 11-21-2013, 10:13 AM
charles Tauber charles Tauber is offline
Registered User
 
Join Date: Feb 2011
Posts: 8,381
Default

The usual cause for uneven response from a piezo-electric under-the-saddle pickup is uneven pressure from the saddle on the transducer (strip). A common cause of that is that the bottom of the saddle isn't flat and square, or the bottom of the saddle slot isn't. Another often-seen cause is that the saddle is a little too tight in the slot, preventing the saddle from contacting the transducer as it should.(The saddle should be an easy slide-in fit, but not sloppy or with play: the saddle should not tip in the slot due to a loose fit.)

One remedy is to sand the bottom of the saddle dead flat. Another is to place a small rectangular piece of standard writing paper, a single sheet thickness, under the saddle beneath a string that is more quiet. Doing so is an attempt to rectify the unevenness of saddle pressure.

This is a common issue with this type of pickup.
Reply With Quote
  #5  
Old 11-21-2013, 10:36 AM
arie arie is offline
Registered User
 
Join Date: Jun 2009
Posts: 2,728
Default

in toolmaking we would use "Prussian Blue" which is an ink of incredible spreading properties used to mate tight fitting parts together by observing where the dye transfers from one part to another then lapping down the "high spots" until the desired fit is made. now i'm not suggesting to use that stuff on a guitar, but perhaps there is something else that is more instrument friendly like chalk, etc... that one could use for the same effect to ensure the best possible fitment of the transducer to the bridge pocket. i'm not a repairman (i build) but it's just a suggestion.
Reply With Quote
  #6  
Old 11-21-2013, 11:25 AM
stanron stanron is offline
Registered User
 
Join Date: Mar 2011
Posts: 2,428
Default

In areas where access makes it possible I have used cue chalk to get surfaces to match. Also The lead from a soft pencil will transfer from one surface to another. When the surfaces are dark plain white chalk can work.
Reply With Quote
  #7  
Old 11-21-2013, 02:14 PM
Monk of Funk Monk of Funk is offline
Registered User
 
Join Date: Jan 2013
Posts: 962
Default

I saw on youtube once somebody put, I think it was permanent marker along the bottom of the bridge, and then sanded on a flat surface. Once the marker was completely gone, then you know it is flat. This first requires the commitment that you will sand it though.

That sounds like an easy enough fix though. Thanks. I'll let you know how it went.
Reply With Quote
  #8  
Old 11-21-2013, 02:25 PM
Tony Done Tony Done is offline
Registered User
 
Join Date: Oct 2013
Location: Toowoomba, Australia
Posts: 2,014
Default

Assuming the bottom of the saddle is flat (I use a file, not abrasive paper), and you aren't equipped to level the bottom of the slot, you can fix them by shimming the weak section between the saddle and the pickup.It usually takes very little - often a single layer of adhesive tape or thin shim stock (eg soft drink can) is enough - but can take a lot of fiddling about to get it just right. Another trick is to cut a keyhole slot or slots in the saddle so it will flex a bit under downward string pressure.
Reply With Quote
  #9  
Old 11-21-2013, 03:07 PM
charles Tauber charles Tauber is offline
Registered User
 
Join Date: Feb 2011
Posts: 8,381
Default

Quote:
Originally Posted by Monk of Funk View Post
Once the marker was completely gone, then you know it is flat.
Once the marker is completely gone, all you know is that you have abraded the entire surface. It doesn't ensure the surface is flat.
Reply With Quote
  #10  
Old 11-21-2013, 04:05 PM
Monk of Funk Monk of Funk is offline
Registered User
 
Join Date: Jan 2013
Posts: 962
Default

Quote:
Originally Posted by charles Tauber View Post
Once the marker is completely gone, all you know is that you have abraded the entire surface. It doesn't ensure the surface is flat.
Well, you need to make sure that you are sanding on a flat surface, and sanding in a "flat way". It might be crooked, or on an angle, but if do it right, it should mean that it is flat, or at least level. If the surface isn't flat, or you're not keeping it steady, then it won't be.
Reply With Quote
  #11  
Old 11-21-2013, 05:36 PM
Tony Done Tony Done is offline
Registered User
 
Join Date: Oct 2013
Location: Toowoomba, Australia
Posts: 2,014
Default

Quote:
Originally Posted by Monk of Funk View Post
Well, you need to make sure that you are sanding on a flat surface, and sanding in a "flat way". It might be crooked, or on an angle, but if do it right, it should mean that it is flat, or at least level. If the surface isn't flat, or you're not keeping it steady, then it won't be.
Some USTs are very sensitive to contact irregularities. I finish my saddles on a file, with the file laid on the bench and the saddle rubbed on it. I've found it is less likely to result in convexity than abrasive paper. If I do use abrasive paper for flattening anything, I stick down to a sheet of glass or metal with double-sided adhesive tape. I use pencil or marking pen on the bottom of the saddle to check progress. I finally check for flatness against the edge of a steel rule, held up to the light.
Reply With Quote
  #12  
Old 11-21-2013, 06:30 PM
Monk of Funk Monk of Funk is offline
Registered User
 
Join Date: Jan 2013
Posts: 962
Default

Quote:
Originally Posted by Tony Done View Post
Some USTs are very sensitive to contact irregularities. I finish my saddles on a file, with the file laid on the bench and the saddle rubbed on it. I've found it is less likely to result in convexity than abrasive paper. If I do use abrasive paper for flattening anything, I stick down to a sheet of glass or metal with double-sided adhesive tape. I use pencil or marking pen on the bottom of the saddle to check progress. I finally check for flatness against the edge of a steel rule, held up to the light.
Thanks. I assume you mean the under saddle pickup when you said UST, but what does it stand for?
Reply With Quote
  #13  
Old 11-21-2013, 07:49 PM
charles Tauber charles Tauber is offline
Registered User
 
Join Date: Feb 2011
Posts: 8,381
Default

Under Saddle Transducer.

A transducer is a device that converts energy from one form to another.

The piezo electric effect is that certain materials generate a small electric charge as a result of small (elastic) deformation of the material. That is, a mechanical force applied to the material causes the material to generate a small electric charge.

Under the saddle transducers include piezoelectric materials in their constructions. The magnitude of the signal generated is proportional to the magnitude of the force applied to it. If more force is exerted from one string pressing on the saddle, compared to the force exerted by another string, the magnitude of the output (volume) will vary. Hence the importance of equalizing string pressure/contact on the transducer.
Reply With Quote
  #14  
Old 11-21-2013, 07:52 PM
simply rod simply rod is offline
Registered User
 
Join Date: Jun 2013
Location: Japan
Posts: 226
Default

I've had some success with self-hardening clay under the piezo UST. However, I try to avoid piezo USTs whenever possible.
Reply With Quote
  #15  
Old 11-21-2013, 09:20 PM
Monk of Funk Monk of Funk is offline
Registered User
 
Join Date: Jan 2013
Posts: 962
Default

Quote:
Originally Posted by charles Tauber View Post
Under Saddle Transducer.

A transducer is a device that converts energy from one form to another.

The piezo electric effect is that certain materials generate a small electric charge as a result of small (elastic) deformation of the material. That is, a mechanical force applied to the material causes the material to generate a small electric charge.

Under the saddle transducers include piezoelectric materials in their constructions. The magnitude of the signal generated is proportional to the magnitude of the force applied to it. If more force is exerted from one string pressing on the saddle, compared to the force exerted by another string, the magnitude of the output (volume) will vary. Hence the importance of equalizing string pressure/contact on the transducer.
Oh, thx.

What other sorts of pickups are there for acoustic, that will come stock with the guitar?
Reply With Quote
Reply

  The Acoustic Guitar Forum > General Acoustic Guitar and Amplification Discussion > Build and Repair

Thread Tools





All times are GMT -6. The time now is 05:10 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright ©2000 - 2022, The Acoustic Guitar Forum
vB Ad Management by =RedTyger=