Soundpost?

Greg Clinkingbeard · #1 01-01-2010, 10:46 AM

I've had an old flatback since early summer which underwent a full restoration just before I bought it. The bass sounds fantastic but I have been a bit bothered by the E string.
It sounds overly resonant with more overtones and a bit less fundamental than the other strings. It has kind of a boink tone if that makes any sense. The D and A are the strongest strings on this bass.
The soundpost is currently at the outside edge of the bridge foot and about 3/4" below. Too tight?

forester · #2 01-01-2010, 01:24 PM

tight to me is when someone yanks it in and then tensions up the strings...
you could try moving it inboard a bit and see if there is any definitive change in the E.
does the bottom your SP sit on the bracing like many older flatbacks.

drurb · #3 01-01-2010, 01:34 PM

Quote:

Originally Posted by forester

tight to me is when someone yanks it in and then tensions up the strings...
you could try moving it inboard a bit and see if there is any definitive change in the E.
does the bottom your SP sit on the bracing like many older flatbacks.

Hmm... I think "too tight" is usually evaluated with a bit more finesse than that.

Also, I'd recommend that a qualified luthier be involved in making changes to the SP position. One of the many reasons is to make sure that, once moved, the post is flush against the top and back.

forester · #4 01-01-2010, 01:40 PM

yea..your right..i deal with a lot of factory installs

Ken McKay · #5 01-01-2010, 01:44 PM

Terminology can sometimes confuse the issues.

The fundamental of the E string on a double bass is always weak but the ears fill it in. The true fundamental comes in around the open A string with a whoosh of air sound, which is usually around 65 hz. This is the so called A0 resonance. On the good basses that I have heard, it is pretty obvious if you are paying attention. Again this is normal and usually would not be something you would want to try to change. Changing this would be to somehow make the bass sound less powerful when the A0 frequency gets obvious.

You can't tell if the post is tight by describing its position. It could be loose there too.

Greg Clinkingbeard · #6 01-01-2010, 05:17 PM

Forester: Yes, the post sits on the wide horizontal brace like most of the flatbacks I have seen.
Ken: What you say makes alot of sense as I do believe the resonant frequency of the body is close to the open A. The bass is very powerful and even from there all the way up the bass.
Of course, I know a post can be tight regardless of position.
My thought is that the lower strings should get louder with the post moved more toward the outside, no?
It could be that moving it more to the inside would help the definition on the E as it is now a bit flabby.
I will probably take it in to have it checked out as it seems to have changed a bit going into winter. That was the reason for suspecting that the post might be tight.

Ken McKay · #7 01-01-2010, 06:42 PM

Yes, it does appear to be apost position change might help even it out. Sometimes it needs to go in though towards the center so it is not too tight. OTOH, sometimes moving it out, but shortening it is the ticket.

drurb · #8 01-02-2010, 01:24 PM

Quote:

Originally Posted by Ken McKay

The fundamental of the E string on a double bass is always weak but the ears fill it in.

Actually, what the brain fills in is the pitch of the fundamental. It does not add any perception of the strength of the fundamental vis a vis the harmonic series. While the strength of the fundamental of the E (~41 Hz) is reduced in perceived loudness, it is not absent-- at least on my bass!

Greg Clinkingbeard · #9 01-04-2010, 05:16 PM

Thank you all for your input. As I suspected, the post was tight; so tight that my luthier had to bring out the big hammer to get it out. It got chewed up a bit in the process so he cut a new one a bit shorter and set it about 15mm to the inside and a bit below the old one. This took a lot of tension off the bass and it is much happier this way.
I should have had it checked months ago but it survived my neglect.

forester · #10 01-04-2010, 07:04 PM

clink,
good move..you have no doubt saved yourself and your bass future trouble. i have an old flatback like yours,luckily it has large ff's and i can set my SP with my ring and middle fingers very close to where it needs to be.it will touch top and bottom but will not stand on its own, i tension the D&A strings while still holding it in place,and make the final adjustments when fully strung. that way I know it is not too tight,and it just routine whenever other work needs to be done.