Official Luthiers Forum!

Solely owned and operated by Lance Kragenbrink
It is currently Sat Nov 18, 2017 5:14 am


All times are UTC - 5 hours





Post new topic Reply to topic  [ 5 posts ] 
Author Message
PostPosted: Sun May 01, 2011 7:03 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Wed Oct 22, 2008 9:31 pm
Posts: 1877
First name: Darryl
Last Name: Young
State: AR
Country: USA
Focus: Build
Status: Amateur
I'm about to start a square neck resonator build for a friend using Claro Walnut. I purchased the Beard plans which show traditional soundwell construction. I like the idea of using post construction with an open soundwell and that's what I will do on this build.

On the open soundwell construction using posts to support the cone, it appears most folks use a baffle that mostly blocks off the upper portion of the upper bout and the shape and location seem to be directing air out the sound ports. From what I've read on several folks posts, it can be tricky locating and shaping the baffle to optimize the tone. Some folks have added baffles and the tone worsened instead of improving.

So it appears the baffle is doing two things, 1) affectively reducing the volume of the box and 2) directing air flow through the sound holes.

As far reducing the interior volume of the box, this is odd in that the trend is toward larger sized resonators.......even some shaped and sized like a dreadnaught where the traditional size/shape was more like a classical guitar. I've also read a post where it's stated that as the box gets larger, it gets more difficult to get the location and shape of the baffle right so it sounds nice. But it seems folks think the larger bodies sound better.

So putting all this together, I'm wondering if the traditional sound holes (or ports) are undersized for squareneck resonators using open well construction techniques. If blocking off part of the interior volume improves the tone, seems one could make a larger sound hole instead of reducing the air volume inside the box. If locating and shaping the baffle to improve air venting in/out the sound holes improves tone, seems you could achieve the same affect just by enlarging the sound holes.

A 000 body has a 4" sound hole which is 12.57 sq. in. My Beard plans show (2) holes each 2.375" diameter which 8.86 sq. in. (for both holes combined). Now 2 holes won't allow air to flow as easily as a single hole with equvalent area due to more boundary conditions which makes the situation worse for the resonator. Now add sound hole screens and you block off a significant portion of these 2 sound holes. Now I'm not sure that a resonator needs as large a sound hole as does an acoustic guitar but if adding baffles to decrease volume and direct air flow are improving tone, it makes me think the current standard is undersized. Also, if using the same baffle to control internal volume and direct air flow out the sound ports, I can see where it would be finicky to tune properly.

Beard a new model called the Odyssey which has a large body and a single, centrally located, oval shaped sound hole. I've read several posts where folks have discussed how good these sound and recently on David Letterman and on Jay Leno, Jerry Douglas was playing the Odyssey model. I'm wondering if using one larger, centrally located sound hole is giving the new model improved air flow and responsible for some of the tonal improvements. It appears Beard couldn't make the sound hole any larger and still fit between the cone and the fretboard extension so he made it oval shaped so he could enlarge it even more. Now I've recently read that even this model still has a baffle (though not sure where it's located or the shape of the baffle) so it's possible it still doesn't have sufficent air flow (assuming the baffle is either reducing internal volume or directing air out the sound hole. Beard claims the size/shape of this sound hole (and I might add "location") greatly improve the bass response generating "stonger, deeper, tighter bass." To balance the bass they then use a polished cone which adds to the high frequency response giving a large, balanced tone to the new instrument. Just my observation but it seems the single sound hole, location, and size creating better air flow is what is responsible for the better bass response.

Thoughts?

_________________
Formerly known as Adaboy.......


Top
 Profile  
 
PostPosted: Mon May 02, 2011 11:29 pm 
Offline
Cocobolo
Cocobolo
User avatar

Joined: Wed Aug 11, 2010 8:31 pm
Posts: 103
Location: St. Louis, Missouri
First name: Kenneth
Last Name: Jeffs
City: Chesterfield
State: MO
Zip/Postal Code: 63017
Country: USA
Focus: Build
Status: Amateur
Darryl,

I read the post and comments in the other RN forum (can I say that here) and this is very interesting. I see your point do follow its logic. Your principles are well thought out and provide nice food for thought and possible discovery. I do agree with the posting that theorizes on how important the variable factors of box construction (size, weight, bracing, etc. are on the final sound and would speculate that a baffle (senza or location) would be best made after the box is closed. That said, this really creates a whole new set of problems with tearing down for each trial location (or removal). I should not post this but I am not here to create new patents, so here goes, I wonder if anyone has thought about devising a way to modify the baffle location, angle, etc as part of the build. Much like a tunable box. A mechanical process that could be manipulated from outside the box. Maybe overkill maybe not, but fun to think about. I can see the ad header now, New and Improved Tunable Resonator Box, with just a slight adjustment your resonator too can sound like Flux, Oswald, or Uncle Buck. Hurry before they are all gone... :)

Seriously, I am not making light of your post but who knows the next resonator innovation...

Ken


Top
 Profile  
 
PostPosted: Thu May 05, 2011 9:22 pm 
Offline
Contributing Member
Contributing Member
User avatar

Joined: Wed Oct 22, 2008 9:31 pm
Posts: 1877
First name: Darryl
Last Name: Young
State: AR
Country: USA
Focus: Build
Status: Amateur
On this first build I'm considering also making a plywood top and put it on with a paper gasket around the perimeter so it can later be removed. Then I can play with different size sound holes and see what size sound hole sounds best. Start out small and keep opening up the hole. Hopefully, it would keep sounding better and better and then when you get too large it would start sounding worse. Once you've gone too far you can always stick a tube in the opening and play with the tube depth to simulate a smaller opening. Once I've found the size sound hole that works well, then I can cut that size hole in the permanent top at the same location(s).

_________________
Formerly known as Adaboy.......


Top
 Profile  
 
PostPosted: Fri May 06, 2011 9:29 pm 
Offline
Cocobolo
Cocobolo
User avatar

Joined: Wed Aug 11, 2010 8:31 pm
Posts: 103
Location: St. Louis, Missouri
First name: Kenneth
Last Name: Jeffs
City: Chesterfield
State: MO
Zip/Postal Code: 63017
Country: USA
Focus: Build
Status: Amateur
Interesting concept. Have you ever used a paper gasket joint before? What about hide glue? I use it and with minimal stream it comes apart quite easily.


Top
 Profile  
 
PostPosted: Fri May 20, 2011 8:14 am 
Offline
Walnut
Walnut

Joined: Sun May 16, 2010 7:02 am
Posts: 10
First name: Dennis
Last Name: Poague
City: Belo Horizontes
State: <inas Gerais
Zip/Postal Code: 31365500
Country: Brazil
Focus: Build
Status: Semi-pro
Bo-dGreetings from Brazil,
I am a Conehead Luthier from USA living here 22 years. I spent the last ten years in heavey R&D trying to discover the secrets of Tap Tuning..and cone spinning...the two most fundamental parts to develop the perfect sounding Reso/dobro. I finally gave up on the cone spinning due to no supply of aluminum (6061 T1) but I did buy the Roger Siminoff book `the Art of Tap Tuning`and found the Holy Grail for tuning the instrument...only problem is the book doesn´t supply any target tuning data for reso/dobro instruments...do any of you master Conehead luthiers have any info like brace tuning or cone tuning or soundhole tuning...this info would help answer this topic about using baffles, soundhole location and size, etc with some hard data.
I have been restoring old DelVecchio dinamics and have built a couple Hybred acoustic reso electrics with soundholes and fHoles..but that was before I got the book and now I plan to build with documentation to answer these topics...just hoping somebody there has done some prior research to point me in the right direction...most luthiers I have researched stick with the data from the Old National/dobros built by the old departed founders of those instruments as reference..anybody try laminated bracing ala Larsen brothes for Reso/Dobro construction...or LuteHole adjustable soundhole covers placed in the baffle or sound holes...I recently built a Bo-didly style resolectric out of briefcase with four soundholes( planning to put amp with speakers in bottom two holes...with aluminum insert soundwell and cone bought from Casa Del Vecchio 5 years ago...gets alot of attention cause Reso/Dobro is rare animal in these parts, BoDidly is rarer, one of a kind....no Bluegrass in Brazil..ciao


Top
 Profile  
 
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 5 posts ] 

All times are UTC - 5 hours


Who is online

Users browsing this forum: No registered users and 2 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group
phpBB customization services by 2by2host.com