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Spruce bridges?!

Luttgutt - 4-29-2010 at 03:27 AM

Hi!

Why isn't spruce been used to make bridges?

According to my calculations, Sitka spruce has one of the highest speed of sound index!

What am I missing?

ALAMI - 4-29-2010 at 03:38 AM

I think that spruce is too soft to serve as bridge, may be the strings would cut through.

What I know is that many Nahats have a spruce core inside the neck and this soft core is covered with walnut, or other wood, from the back and a hardwood as fingerboard, it seems it is not a widely known information as it can only be seen from the inside by those doing a neck reset.
may be they did this for the sound index you're mentioning

Sazi - 4-29-2010 at 03:40 AM

Try one and see

No don't! - bridges need to be hard enough to withstand quite a lot of pressure, spruce is way too soft! If it were a floating bridge the strings would press through it and if it were fixed they would slice through it.

Luttgutt - 4-29-2010 at 04:57 AM

Then why not do with bridge the same that is done to necks?
i.e. Spruce core, coverd with wallnut (for example)?

Sitka has density 0,40 (same as Mahogany) while walnut is about 0,50.

So... is sitka pruce THAT soft really to make a bridge??

ALAMI - 4-29-2010 at 05:10 AM

Well we can imagine a reinforced spruce bridge, may be using bone -on top and sides of the bridge- so the strings wouldn't cut the spruce, but still, the spruce base of the bridge has to be glued to the face and the spruce internal structure has to sustain and transmit the stress and shear force to the face, can spruce do this without getting deformed ?

I don't know, maybe no one ever tried it on oud but probably if it can be done some guitar maker could have tried.

ALAMI - 4-29-2010 at 05:40 AM

Curiosity can be contagious, so following up on the above, it seems that spruce bridges are standard for the huge Mariachi guitars, it came a lot in the search:
http://www.instrumentalley.com/Lucida-LG-GR1-Guitarron-Mariachi-Gui...

And at least one person is using spruce bridges for Mandolin
http://www.nkforsterguitars.com/news

Sazi - 4-29-2010 at 02:53 PM

Hmm, although they say the Mariachi bridge is spruce it certainly doesn't look like it...

The Mandolin Spruce bridge with the bone saddle looks like it may be a good option for floating bridge oud, notice the direction of the grain, paralell to the soundboard like western Lute braces.

I'll see what I have and make one to try out of curiosity...

Thanks for the interesting posts!

Sazi - 4-29-2010 at 08:52 PM

Ok, well, as I said, I don't know about using spruce for a fixed bridge, what with the re-enforcements likely necessary etc. I don't think the result would be worth the extra time and effort...but...

I just made a spruce floating bridge using an old brace which just happened to be parallel grained - for my Laith Fouad Jihad oud.

Unfortunately I don't have recording ability at the moment so I'll try to explain what I thought...

I was pretty happy with the sound as was, but although it was nice and even across the strings I felt it was lacking a certain character that I like, that Munir Bashir-type resonance in the highs, so interestingly had made a new bridge just before I read this thread! The wood of the original bridge is Indian Rosewood, which is a good choice, but the new bridge I had just made was Walnut, which to my ear gives noticably more over-all volume and a pleasing open-ness and liveliness to the sound in the upper harmonics.

Replacing that with the spruce bridge I was hard put to choose between the two, eventually deciding that I preferred the walnut, perhaps it had slightly better sustain, but I felt the spruce was an improvement over the Rosewood.

So... it works, but you'd have to try it for yourself on your own oud that you know the sound of to see/hear if it works for you.

Luttgutt - 4-30-2010 at 04:49 AM

Thanks a lot ALAMI for the links (beautiful spruce bridge!)

And thanks for the comparition Sazi, I'll try it on my two floating ouds (thanks for ointing out the direction of the grain!)

Luttgutt - 5-5-2010 at 05:25 AM

Quote: Originally posted by Sazi

notice the direction of the grain, paralell to the soundboard like western Lute braces.

Hi Sazi!

how were you able to see the direction of the grain? I can't see it

So, what do you mean by direction of the grain is paralell to the soundboard? (I am trying to make a new bridge)

Thanks again

Sazi - 5-5-2010 at 05:34 AM

You can see the grain better on this pic:

http://www.nkforsterguitars.com/public/uploaded//guitars/140.jpg

Not sure if it would make much difference which way it went though...

I've tried it on a couple other ouds and maybe it's just the one I made (I didn't have any bone the right size) I liked the tone of it but it definitely seemed to cut the sustain a bit, maybe that's not so bad for a mandy but I prefer lots of sustain on my floating bridge ouds.

Luttgutt - 5-5-2010 at 06:06 AM

I see! Thanks!
I'll try... have nothing to loose anyway

One more thing:

What about the "openings"/"tunnels" under the bridge? what defference does it make?