new back?

[Arnold Schnitzer]

To amplify Ken's point above--the main problem is that flatbacked basses usually have crossbars running 90 degrees to the back wood. This is considered a no-no in woodworking, because wood expands/contracts mainly across its width, and cross-grained joints will blow themselves apart when the weather changes. (Or, if the joint does not fail, cracks and warpage will be the result.) Crossbars are the reason flat-backs fail.

[Ken Smith]

Originally Posted by Arnold Schnitzer

To amplify Ken's point above--the main problem is that flatbacked basses usually have crossbars running 90 degrees to the back wood. This is considered a no-no in woodworking, because wood expands/contracts mainly across its width, and cross-grained joints will blow themselves apart when the weather changes. (Or, if the joint does not fail, cracks and warpage will be the result.) Crossbars are the reason flat-backs fail.

Sounds like Job security to me Maestro..

I have seen a new maker doing this still and 'way' over bracing the Back as well. These are not very expensive basses. When they fail, the owners will be 'buying' the bass all over again..

I think a person should be very experienced in making basses before he starts building them. This way, 'mistakes of the future' might easily be avoided..

[Ken McKay]

You can prevent future cracking by proper cross grain gluing, done at proper relative humidity, when glued with overly dried back wood, with a dome shape. Plus, you have to know your wood! Live and sleep with it is best.

[Arnold Schnitzer]

Originally Posted by Ken McKay

You can prevent future cracking by proper cross grain gluing, done at proper relative humidity, when glued with overly dried back wood, with a dome shape. Plus, you have to know your wood! Live and sleep with it is best.

Ken, I agree that controlling the moisture content of the wood, and gluing up in a low RH atmosphere helps, but there will still be problems if the bass lives in an environment where the temperature and humidity go through large swings. Not to mention the fact that gluing in the crossbars re-introduces water into the wood. Owners of flat-backed basses with crossbars (who live in temperate areas) should expect occasional loose braces and cracks; it's par for the course.

[Ken Smith]

Originally Posted by Ken McKay

You can prevent future cracking by proper cross grain gluing, done at proper relative humidity, when glued with overly dried back wood, with a dome shape. Plus, you have to know your wood! Live and sleep with it is best.

Here are some links of the Backs of some of the Basses that I have, have come and gone or are in restoration as we speak that have had Back Repairs/Restorations due to the reasons stated above. Depending on the Bass and the situation, the Bracing system was either done as before, modified to a different style or was modified already and just left as-is. Still, the repair history of every bass shown indicates that in the Northeast, a Flatback can be hazardous to its own health.

Here they are in no particular order.
one , two , three , four , five , six , seven , eight , nine , ten

A Bass can be 200 years old or brand new. Once it goes thru a Northeast Winter or two and has never been repaired or modified you will see what things are possible. Roundbacks do a little better but they move as well.

With all of that said, some of my favorite Basses are Flatbacks and I continue to buy them regardless.

[Martin Sheridan]

I have seen a few flat back basses with only one brace in the back for the soundpost and they seem to have held up very well.
Also, I think the X Brace is supposed to help the cracking problem, but I haven't tried it myself. Didn't someone say that Prescott introduced the X Brace?
Generally I prefer flat back basses.

[Ken Smith]

Originally Posted by Martin Sheridan

I have seen a few flat back basses with only one brace in the back for the soundpost and they seem to have held up very well.
Also, I think the X Brace is supposed to help the cracking problem, but I haven't tried it myself. Didn't someone say that Prescott introduced the X Brace?
Generally I prefer flat back basses.

I have never seen a Prescott with an X-brace but I did hear of him doing this. Also, there are so many Yankee basses 'named' Prescott that in my opinion are just not. If one of these Prescott 'like' basses had the X then it would be possible that he was credited with something that he never actually did. On the Prescott theory, how many basses like this, Prescott or others still have their original Braces? Yes you can see scars of previous work but still, you have to make sure what's original before giving a maker a particular claim.

I know of two basic X patterns. One with a lap joint in 2 pieces in total and one without the joint, 3 pieces. The longer piece under the 'post being solid with 2 attached pieces forming the X.

Then, there is the quasi half-X. I have that on two basses now with a third in restoration getting it as well. One long single slanted piece and a smaller angled bar opposite it at the lower bout. Sometimes another piece at the top.

On the French Basses with the single 'step' like center brace these are theories about this. My Mougenot is like that but the center seam has opened up from the bottom all the way up about 2/3 of the way. Now, the Back has to be rejoined with possibly a center strip added. I don't think it will be a single brace when it goes back together.

On a roundback, a single center brace is nice to have as well. It helps to spread the sound across the back and takes the pressure off a single place under the post. In this case, if the Post gets tight in the winter, it will most likely open a c-bout seam on that side, top or back. I had two openings this winter. The back on a flatback and the top on a round back. No splits, just a seam and a sign to check the post fit.

[Matthew Tucker]

Originally Posted by Ken Smith

It helps to spread the sound across the back ...

How can you tell that the sound is spreading across the back?

[Ken Smith]

Originally Posted by Matthew Tucker

How can you tell that the sound is spreading across the back?

Because two of the Basses we added this brace to were in my possession before the brace was in and I know the sound before and after. Also, where else is the sound being transferred in your mind from this addition, the scroll?

Try it yourself with a few old Italian Basses with Oppio backs and get back to me. Make sure you know what the bass does before hand as well so you can make a good post brace audible assessment. Playing the basses in a symphony Orchestra before and after is the best test. Ask the concert master across the stage what he hears differently.