top voicing - before or after gluing to the sides?

[hat]

I think the standard method of voicing is usually done prior to gluing the top onto the sides. But that can change the stiffness, and top activity, if that makes sense. I just wonder how many of you luthiers go back in and re-voice after gluing the top and sides together? Or do you wait until the box is fully enclosed to do a final tuning, or maybe both?

[SteveS]

I voice the top with the back off and rim on. That works best for me, but may not for you.

[Tom West]

I work the braces with the top off the rims...........work more with the rims on.......and finally check resonances with the box together and do some adjusting if called for. Each stage generally gets progressively less as to amount of work done.
Tom

[dekutree64]

Originally Posted by Tom West

I work the braces with the top off the rims...........work more with the rims on.......and finally check resonances with the box together and do some adjusting if called for. Each stage generally gets progressively less as to amount of work done.
Tom

Yep, it's a gradually refined thing, not done all at one stage.

With the free plate, you can flex it to feel the stiffness. Good information that's not available once it's glued to the rim.

When glued to the rim, you can shave the brace ends and tap on it and hear the effect of perimeter stiffness, which isn't really audible with the free plate.

With a closed box, you hear the interaction of the top/air volume/back. Usually by this point I'm happy with the top, so I tune the back to work with it. I actually do this before closing, by spool clamping the back on and tapping, but you can just reach through the soundhole to carve braces too. I also record the taps and look at the frequency plot in Audacity to be sure that I'm hearing what I think I'm hearing.

If you use fairly thick tops, you can wait until the box is closed to do the perimeter stiffness, by sanding the plate thickness rather than carving brace ends. Some classical builders even wait until it has string on

[Alan Carruth]

I try to do as much tuning of the top as I can before I glue it down, using the Chladni technique. After that I don't see much utility in tuning the top on the rim with no back, since the mass and flexibility of the sides alters things. Tuning it with the box closed is a pain for me because my arms are too fat, which is why I try to get it right before that.