at what point is a bass considered a hollow-body?

jordan_frerichs · #1 01-26-2009, 03:31 PM

what is the line that separates a bass that is execive chambering, and a bass that is a hollowbody? i have hollowed out the wings of my project completly. exept for the front arm contour. i have a more than average sized area behind the bridge, that i plan to hollow out, and put a top on as well (it s a neck through, so i am curious how facing that section will go). i have routered the sides of the wings that will be glued to the neck, in the areas where the jazz pickups will be and behind the bridge location. my goal is, instead of 2 hollow wings separated by a solid core, to have a continous hollw space, that runs through most of the body with the bass still being structurly sound. i am wondering if i hollow out the body core behind the bridge, and have the internal hollow space run through the wings and core, as well as a connection of space through the jazz pickup routes, will it be a hollowbody instead a chambered body?

roberthabraken · #2 01-27-2009, 05:10 AM

In my opinion.. a hollow-body is build exactly like an acoustic (bass) guitar, with bent sides and all..

I think a bass with a solid body that is chambered, should be called semi-hollow.

But I guess this is a matter of opinion anyway

bjlevine · #3 01-27-2009, 08:34 AM

Yeah, I'd have to agree. If its basically one piece of wood, it's not a hollow body.

Arx · #4 01-27-2009, 01:31 PM

Who cares what it's "considered"

If it sounds like you want it to, that's all that matters.

-Nick

ehque · #5 01-28-2009, 01:13 AM

Any body which allows either the bridge or the pickup to resonate independently of the rest of the bass, is a hollow, to me. A bass with hollow wings and solid core, since it falls outside this category, to me is still solid.

jordan_frerichs · #6 01-28-2009, 07:44 AM

what i am shooting for, is semi-acoustic.... i guess enough to be more audible and louder than solid-bodied basses unplugged. i will try and get pics of the hollowed wings, and how i am going to hollow out the core, and connect them.

roberthabraken · #7 01-28-2009, 08:02 AM

Quote:

Originally Posted by jordan_frerichs

what i am shooting for, is semi-acoustic.... i guess enough to be more audible and louder than solid-bodied basses unplugged. i will try and get pics of the hollowed wings, and how i am going to hollow out the core, and connect them.

Then you should bend the sides and have separate top and bottom.. just hollowing out a solid body doesn't give you an audible sound playing unplugged.

Arx · #8 01-28-2009, 01:18 PM

Quote:

Originally Posted by roberthabraken

Then you should bend the sides and have separate top and bottom.. just hollowing out a solid body doesn't give you an audible sound playing unplugged.

It won't be nearly as loud as a true acoustic style instrument with bent sides, but assuming the body is hollowed under the bridge and the bridge is far enough from the edge of the body that it can actually resonate the top, it should be fairly audible. (for practicing alone, etc)

Of course, that's assuming it's structurally sound, and doesn't just tear the bridge off, since solidbody basses often use different wood that may not be tough enough when sufficiently thinned.

jordan_frerichs · #9 01-28-2009, 02:50 PM

the top and back are 1/4" flamed maple, the sides are 1/2" of mahogany. the back edge of the bass is roughly 3-4" from the back of the bridge. i thought i was sopposed to leave that area solid for the screws (its a 3 screw schaller) how should i go about hollowinng that area

vbasscustom · #10 01-28-2009, 02:54 PM

put a bridge plate under it, but leave a spot for pickups, and get that thing done already man, i wanna see her

Arx · #11 01-28-2009, 05:52 PM

Quote:

Originally Posted by vbasscustom

put a bridge plate under it, but leave a spot for pickups, and get that thing done already man, i wanna see her

Yeah, that's pretty much how I'd do it. Leaving it solid under the bridge will probably work better from an electric bass perspective, since it'll be more rigid, and a lot stronger, but if you want it to behave like an acoustic, the bridge is the main source of vibration for the body.

Of course it's going to be much more fragile than a standard electric bass.

-Nick

jordan_frerichs · #12 01-28-2009, 07:45 PM

could you explain a little further into the bridge plate? i want that area to be strong enough to not have to worry about problems. it has bit more tension than a regular 4 string, since it is an octive/8 string, but the scale is reduced to 32" i am not sure what reinforce it with, or whatever i need to do. i am still learning. this is my second build, and most of my knoledge is for solid bodies, and a little with chamber instruments

vbasscustom · #13 01-28-2009, 07:51 PM

well, put a flat block of nice spruce or something under the bridge, like they do on acoustics. im not sure it if will work on a bass, but it works for them

Arx · #14 01-28-2009, 08:32 PM

Pretty much, you just want it supported so the screws have something to grab into. 1/4" of wood might be pushing it.

Alternatively, you could just leave it a bit thicker in that area. The main point is that if it's too solid and can't flex at all, you're going to get a lot less sound out of it.

In an acoustic guitar it's done that way because they're making it out of thin panels of wood. Where you're starting with a block you've got more options.

Don't take my advice alone though. My bass building experience isn't much more than yours. I'm just basing my advice on my knowledge of the physics involved, and my more general building stuff and tweaking experience.

There may be things I'm overlooking. I'm just giving you my hunches... It _should_ work. An acoustic has much thinner wood, and I haven't heard of too many problems with bridges tearing out.

-Nick

jordan_frerichs · #15 01-29-2009, 11:19 AM

Quote:

Originally Posted by vbasscustom

well, put a flat block of nice spruce or something under the bridge, like they do on acoustics. im not sure it if will work on a bass, but it works for them

thanx for all the help everyone!
so would this be glued to the top part, or touch the top and bottom? just large enough for screws to go in, or the size of the bridge unit? you guys think i should ask the luthiers in the mimf forums? they seem to do a lot of stuff like that.
i want to finish this thing too! unfortinately will l only be able do light this-and-that work, because i literally just got out of surgery for a hernia.

Arx · #16 01-29-2009, 12:23 PM

Just attached to the top. Size is probably optional, I'd make it around the size of the bridge.

Asking at mimf is probably a good idea. Anyone who builds acoustic guitars would probably be able to give reasonable advice.

Jehos · #17 01-29-2009, 12:46 PM

These criteria sound sensible to me:

- The hollowness is one chamber that can be said to cover most or all of the body

- There is a sound hole of some kind that allows resonation inside the chamber to come out and be heard

3 big chambers isn't hollow. 2 big chambers isn't hollow. 1 big chamber but no sound hole I'd still consider chambered but I can understand if somebody disagrees.

I guess another way to look at it is that there's way more air than wood inside the body and there's a soundhole.

jordan_frerichs · #18 01-30-2009, 03:33 PM

Quote:

Originally Posted by Jehos

These criteria sound sensible to me:

- The hollowness is one chamber that can be said to cover most or all of the body

- There is a sound hole of some kind that allows resonation inside the chamber to come out and be heard

3 big chambers isn't hollow. 2 big chambers isn't hollow. 1 big chamber but no sound hole I'd still consider chambered but I can understand if somebody disagrees.

I guess another way to look at it is that there's way more air than wood inside the body and there's a soundhole.

-the hollowness is going to be in all of the lower wing, most of the upper, and a good deal of the center section

-there are sound holes

-the chambers in the final bass will not be separated, and become one major chamber.

what has caught my interest, is the bridge, and (spruce) block. i am going to look more into that today.

mrtn400 · #19 01-30-2009, 06:39 PM

I consider a hollow body a bass that has open chamber(s) that do not act as a sound hole.

Like these:
http://www.guitarcenter.com/Dean-Rha...82-i1150773.gc
http://www.guitarcenter.com/Gretsch-...36-i1149613.gc
http://www.guitarcenter.com/Warwick-...34-i1150408.gc

jordan_frerichs · #20 02-01-2009, 12:25 AM

Quote:

Originally Posted by Arx

Pretty much, you just want it supported so the screws have something to grab into. 1/4" of wood might be pushing it.

Alternatively, you could just leave it a bit thicker in that area. The main point is that if it's too solid and can't flex at all, you're going to get a lot less sound out of it.

In an acoustic guitar it's done that way because they're making it out of thin panels of wood. Where you're starting with a block you've got more options.

Don't take my advice alone though. My bass building experience isn't much more than yours. I'm just basing my advice on my knowledge of the physics involved, and my more general building stuff and tweaking experience.

There may be things I'm overlooking. I'm just giving you my hunches... It _should_ work. An acoustic has much thinner wood, and I haven't heard of too many problems with bridges tearing out.

-Nick

i think i may have an idea for this. i am going to glue top AND back pieces to the core section before i glue on the wings. i think will hollow the core piece's bridge section through the back, leaving ?1/4? (do you think it should be more/less?), and leaving support "legs" om the corners of the bridge section. then, hollow behind the bridge, and then a little hole drilling/routing between the pickups, leave at least an edge on both the sides (probly 1/2" wide, give or take), and then glue on the top and back of the core, do a little more routing through the sides, then glue on the wings. is it important for the block to be spruce? the neck is bloodwood and maple.