Double Bass flatback versus carved

[KSB - Ken Smith]

John (CSC), You know the two Shen Basses I have (7/8-800 and 3/4-1000 model). Are you comparing Carved to Flat tone using the EXACT Same Flamed Maple, Plainer Maple or a different wood like the Willow you now use? Have you made an 800 model with the Flat Back in High Figured Maple?

As I stated in an earlier post, accurate comparisons can only be made when all the variables are the same. Different Backs with different woods also throw the tone of the wood into the mix. Two different backs from the same wood/tree with similar figure and grain will make a better test.

Now Bracing.. Test the Bass with regular cross Bars and then pull it apart and replace them with the 'X' system and compare. Same Bass, same Back, Different Bars.... Accurate test!

BTW, DZ brought over a Shen Willow 3/4 last week to show me. Flat Back with X but the bach had a slight Arch to it. Great tone and pretty Bass. I was suprised at the high quality top his Bass had. Not at all what I had expected.. Job well done!

 

[anhmytran]

You can build the curve guitar, or the curve guitar with the Violin shape, and the tone is still good as the flat guitar, if it is not louder and more human like than guitar. The curve shape looks better, and the making is harder. That is the reason Violin is more expensive and it is not flat.

The curve helps different parts of the sound box vibrates independently from one another part. The center of the violin face vibrates more freely than its edges. The violin F holes make this freedom more better. The sound-bar makes this freedom less. That is the reason the violin sound-bar should not reach the edges of the face. In guitar, lacking of the sound-post, the back vibrates far later than its face center where the bridge is on. Guitar has more sound-bars accross the face and the back, that makes the vibration transfering faster accross the face and the back, and also reduces the freedom of vibration of every point on the sound-box. That helps violin sound more human-like and louder than guitar.

Another difference between guitar and violin is the tension the strings on the sound box. Violin tension is more than guitar, for its bridge is higher, the string angle is smaller than 180 degree as guitars. In some guitar, the bridge is not pressing down the face, but pulling the face up instead. That helps violin sound louder than guitar.

Another difference between guitar and violin is that violin bridge is thinner, and vibrates harder more freely than guitar. That helps violin sound louder than guitar.

 

[Martin Sheridan]

I've seen two very old basses with just one brace across the back where the soundpost is. Neither had had back problems, so this might be an option.
Come to think of it, I believe that Gary Karr's "Amati" only has one brace, but I can't remember the condition of the back.
Anyone know?

Incidently Gary told me that he thought flat back basses have a more "focused sound", whatever that means.