Double Bass Sound Post Position Question

[tstone]

I have been reading various opinions about good starting positions for sound posts, but I usually find the descriptions ambiguous and confusing. I am specifically interested in the recommended north/south positioning of the sound post, "north" being towards the headstock, "south" being toward the tailpiece.

It is very common to run across comments like:

"…The sound post must be positioned…between 10 and 15 mm closer to the saddle…"

"…A good position would be 1/2 the diameter of the post distance behind the foot…"

"…The soundpost should be about 20-25 mm below the foot of the bridge…"​

What's frustratingly unclear in all these comments is that the writer does not specify whether he or she is talking about the distance from the center of the bridge foot to the center of the sound post or from some edge of the foot to some edge of the sound post. In some cases, the interpretation could mean the difference between the sound post being partially under the bridge foot or completely clear of the bridge foot.

Is there agreement in the luthier community that a statement like "the soundpost is positioned one inch south of the bridge foot" means either A or B in the figure below? Or is it ambiguous to you too?

I know that all these authors are just talking about starting points, and that adjustments are made by ear therefrom, I just want to understand what the their original meaning was.

 

[Jake deVilliers]

I usually start with a sound post's width between the back of the bridge and the front of the post but the stiffness of the top has to be taken into account as well. A floppy plywood top won't be happy supporting that much pressure whereas a stiff, thick solid top might require more...its not hard and fast.

 

[arnoldschnitzer]

Is there agreement in the luthier community that a statement like "the soundpost is positioned one inch south of the bridge foot" means either A or B in the figure below? Or is it ambiguous to you too?

B is correct.

 

[BassGreaser]

how does the quality of the sound post affect the sound of the bass? I have a Strunal 5/20 hybrid that has the stock sound post..

 

[MIKMAN]

how does the quality of the sound post affect the sound of the bass? I have a Strunal 5/20 hybrid that has the stock sound post..

The stock post is a good one. However if your arco sound is a bit nasal you have to try the following approach: take a thicker soundpost, with a diameter of 19 mm and bevel it, creating a circular contact surface with a diameter of 16 mm in each end. Then fit the new post, experimenting step by step to find the proper spot. The sound will be much better, darker and without the nasal characteristics we find in some Strunals. Then try it with Evah Pirazzi Weichs. You will hear an absolutely different, better instrument. I tried it in six Strunals so far, all hybrids, with impeccable results.
Mike

 

[MIKMAN]

The previously mentioned approach works well with laminated Strunals too. As for the fully carved ones, i have some other hocus-pocus recipies!!!
Mike

 

[cravinho]

The previously mentioned approach works well with laminated Strunals too. As for the fully carved ones, i have some other hocus-pocus recipies!!!
Mike

So, Mikman, any recipe for a Strunal 5/5?

 

[moles]

Did you guys refit the stock post? When I had my 50/4 the original post was waaay long, and besides sounding like arse, it wound up damaging the top and back. At the time I'd come across some info indicating that it was standard for the Strunal factory to fit them like that for shipping purposes. (TBH my Eastman had the same scenario...)
Anyway just curious.

 

[MIKMAN]

Well, the 5/5 is a flat back so the post lies on the brace of the flat back. It means less fitting problems but the proper point has to be found after try and error. Moving the post towards the G string side usually we notice an improvement of the E and A string sound. In some cases the "sweet spot" has been found with the post placed almost in the edge of the G string foot of the bridge. Also i have noticed that the 5/5 basses prefer a thin post of 16 mm with dense grain. There isn't any solid scientific explanation to these observations but i have noticed them to many Strunals and i mention them for any friend who owns one of these basses.
Mike

 

[cravinho]

Well, the 5/5 is a flat back so the post lies on the brace of the flat back. It means less fitting problems but the proper point has to be found after try and error. Moving the post towards the G string side usually we notice an improvement of the E and A string sound. In some cases the "sweet spot" has been found with the post placed almost in the edge of the G string foot of the bridge. Also i have noticed that the 5/5 basses prefer a thin post of 16 mm with dense grain. There isn't any solid scientific explanation to these observations but i have noticed them to many Strunals and i mention them for any friend who owns one of these basses.
Mike

Thanks Mikman! I'll try...

 

[Bryce Van Parys]

between 1/2 diameter to full diameter from the bottom of the foot to the top edge of the soundpost. You may need a guide to get an accurate reading because visually, will be very inaccurate. Thicker tops can get away with post being further if carved. Laminate not as strong, so not more than about 8 mm or 1/2 diameter roughly . Further back gives more booming, bass heavy, loose response, closer is brighter, quicker response, but often thinner and more scratchy. Should fit well and not be in too tight

 

[Bilko]

between 1/2 diameter to full diameter from the bottom of the foot to the top edge of the soundpost.

You said how far below the post should be. And how far sideways towards the rib should the post be?

 

[bassistvp]

In line with the bridge foot, not too far outside so as to be into the line of the "f hole upper turn"

 

[Greg Clinkingbeard]

I'll never have any part of the post outside of an imaginary line drawn from the outside or inside edge of the bridge foot. My starting point is centered on the foot, or between those imaginary lines.

 

[Mr Ralph]

I followed Arnold's instructions for placement and fit on his website and my bass responded very well to that. The only way I think it could sound better was if someone else was playing it.

 

[Turnaround]

I followed Arnold's instructions for placement and fit on his website and my bass responded very well to that. The only way I think it could sound better was if someone else was playing it.

Oooh! I think you nailed my problem.

 

[groooooove]

the post on my bass used to be directly under the bridge foot.

then Jeff Bollbach fit a new post for me and suddenly my bass came to life. i can't say for sure but i'm fairly certain he placed it a soundpost-width south of the bridge foot, measuring from the end of the bridge to the edge of the post.