resonant bass

oldbass · #1 07-14-2007, 09:32 AM

What can be done about a bass that has a body resonance problem. Specifically, at F on the D string (just below the open G) the bass gets much louder than anywhere else. The Fsharp is OK but the E natural is a bit loud also. The F an octave above is a bit bold to but the low F is fine. I cannot detect any loosness or bad glue joints anywhere. (There is no rattle any where) It's just a lot louder on those 2 notes but especially the F. Any thouoghts would be welcome. I have done some repair and setup work on this and other basses so have a bit of experience.

Jamiebass · #2 07-14-2007, 09:54 AM

Are you just experiencing those loud notes at you're rehersal space/home? Or are they that louder in every room you play in?

You might be experiencing standing waves/nodes. They are frequencys that appear louder than others and cause a big boomy sound. They are not due to anything physicaly wrong with you're bass.

They could also be comming from you're cab. Cab's have resonant frequencys as well.

What kind of bass are you talking about?? Woods??

Try listening to some music in the room you are playing in, with a flat EQ, but with a slight bass boost. You will probably hear those frequencys stand out.

drurb · #3 07-14-2007, 09:55 AM

Quote:

Originally Posted by oldbass

What can be done about a bass that has a body resonance problem. Specifically, at F on the D string (just below the open G) the bass gets much louder than anywhere else. The Fsharp is OK but the E natural is a bit loud also. The F an octave above is a bit bold to but the low F is fine. I cannot detect any loosness or bad glue joints anywhere. (There is no rattle any where) It's just a lot louder on those 2 notes but especially the F. Any thouoghts would be welcome. I have done some repair and setup work on this and other basses so have a bit of experience.

Soundpost position?

oldbass · #4 07-15-2007, 01:59 PM

In response to the replies so far--I am aware of the room response effect and have experienced that in other ways and moving to a different room does make a major difference but not with this booming F and though less also E. I haven't tried moving the sound post yet but that is on my list to try.

drurb · #5 07-15-2007, 04:23 PM

Quote:

Originally Posted by oldbass

In response to the replies so far--I am aware of the room response effect and have experienced that in other ways and moving to a different room does make a major difference but not with this booming F and though less also E. I haven't tried moving the sound post yet but that is on my list to try.

I'd recommend having a luthier do any such re-positioning. If the post is to be moved more than a very small amount, a new one should generally be fit.

**Matthew Tucker** · #6 07-15-2007, 05:40 PM

Another thing you can do that doesn't involve going inside is change your tailpiece lighter/heavier, and/or tailgut length.

oldbass · #7 07-16-2007, 08:45 AM

The tail piece advice is interesting. This bass has a tailpiece with the adjustable support points or stops for each of the strings. I have set them so that the string between bridge and tailpiece is tuned to the same note as the adjacent higher open full length string (a few octaves higher of course). On the far end of the G string this turns out to be a C. This was advice a got from a luthier. I can't say that I can detect any significant benefit from doing this compared to just having them at any random position. Is there some other function for the adjustments? I did realize some influence on a wolftone on A when I tried moving them to minimize the wolftone. I appreciate all the helpful suggestions so far.

Silversorcerer · #8 07-17-2007, 07:44 AM

It sounds like you have a Pecanic adjustable tail piece. I think sometimes the real advantage to those is just having some pitches that make sense. I mean the afterlengths are going to be there;- may as well make them sound good.

As far as strong notes on your instrument are concerned, this is not so unusual. There are two major resonances, the cavity resonance and the wood resonance and these usually end up making those notes or close partials of those notes stronger. When it works right, all the notes will sound louder when you play them in tune. Go off pitch and the notes will fade and the notes will not start as easy with a bow if they are off pitch. When it is not working, the instrument has wolfs and very uneven response. Those two resonances are built into the instrument. There are some others as well. The two that can be adjusted are the tailpiece resonance (whole structure) which you can adjust with the tail gut length (you can still tune the afterlengths). and the resonance of the neck and fingerboard, by adding weight to the FB or removing it. And of course open unmuted strings will also resonate. And your endpin will rattle more easily at it's resonant frequency. What you describe with F# and E probably indicates that you have body and wood resonances at those frequencies or frequencies that those are partials of. On my bass, all the Cs are loud.