Official Luthiers Forum!

I'm thinking of buying/making some radius dishes, I was gonna get 15' for the back and 25' for the front my reasoning was I play heavy strings (14-58) and that that would give better structural integrity, but watching John Mayes voicing DVD's I was surprised to hear that a radiused top decreases the bass of a guitar and was wondering what people here build to?

Thanks Guys

John

_________________
Formerly JJH

I learn more from my mistakes than my successes

John,

Ceteris paribus that is true but ceteris are very rarely paribus when you make guitars. In tone terms (in my view and experience) putting an arch in a top will help with mids and trebles and with the volume/projection of the instrument and you have many ways to hunt down the bass you want. 25' is a bit "namby pamby" and gnat's whiskers territory for my building, I use nearer 13' on tops.

Oh yes - some people use arching for structural stability and insurance against variations in humidity.

If you are coming to the Cheltenham Acoustic Gutar Show next weekend, drop by my stand and we can have a more in depth natter about the subject.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

John buddy the decrease is very slight and can be made up for other ways.

Now if this decrease is not psycho-acoustics, and it might be...., it has also been said that building a radius into the back and top increases the mid-range response. A number of makers indicate and believe this and will say so on their web sites with Huss & Dalton being one.

I use a 15 and 25 respectively too and like it. But you will find all manner of radi that people use for various reasons. One of the nice things about 15 - 25' radi is that many of the after market tools, brace shapers, radius dishes, radius templates, etc. are available in these radi.

Dave's arching is well outside what is conventional among modern builders. While I agree with Dave that there is a lot to be done tonally with the arching, a novice builder would do best to stick with convention (25-30' spherical radius for the top) until he knows he is building good guitars in all the other aspects.

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Howard Klepper
http://www.klepperguitars.com

When all else fails, clean the shop.

So Dave does that mean i need only get the 15' dish and use it both front and back and save myself a few bob?

_________________
Formerly JJH

I learn more from my mistakes than my successes

It's really slight. Humidity can move a top more than the difference between 25-28'. All things equal (which they never are) 25' will project slightly more than 28' and the 28' will have slight more low end... Don't sweat the small stuff. There are bigger fish to fry.

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John Mayes
http://www.mayesluthier.com

John,

For reasons so nicely pointed out by Howard, I'm probably not the best person to ask this question - I don't use radius dishes in my building. If you are buying one then as Hesh ponted out, you are probably better getting "conventional" sized ones. As you are in the UK the shipping cost is likely to be "interesting". There are plenty of posts around about making your own - it's messy and you have to have competent skills working with powertools.

A question for you though which is probably a more interesting one for the whole process of designing your instrument - why do you play with 14-58 gauge strings?

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

John, I use the conventional 25'and 15' dishes, made myself from MDF, using a router and guide rails. However, it is a very messy business and ideally should be done outside.

As you're in the UK though I'd suggest you contact Craft Supplies here. I believe that they still sell thier phenolic resin dishes, their last catalogue I had lists both single dishes at £44.95 and a double sided 15'/25' dish at £64.95.

60cm adhesive sanding dishes are avaialble from Axminster for about £8 each.

Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

Colin,

I remembered you saying this in the past and so had a look at the Craft Supplies website. The radius dish doesn't appear there in their guitarmaking tools section. It's probably worth calling them to see though.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

It's in their paper catalogue, I did have an e-mail exchange with them once and they did put it on a webpage, but without the links on their site, but they did send me the link. Do you think I can find it!

Here's from the catalogue.


Colin

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I don't believe in anything, I simply make use of a set of reasonable working hypotheses.

The reason there was I knew nothing when I first started playing and went to a shop in one of these retail outlets and the kids there knew nothing and gave me 13-56 to learn with I asked what was popular and got we sell a lot of these and then was influenced by friends at the folk club I go to all saying the heavier the gauge the better the tone. I had an old EKO with an over thick ply top and got better tone from 13's than 12's so looking through the strings direct catalouge I though let's go up a gauge and didn't really notice a lot of difference, and when I got my all wood Turner just carried on the same as i think the tops a little thick and it may help. Others don't seem to like to play my guitar much I don't know why Now I find myself having not to bend strings when playing theirs Nothings exploded yet.

Don't think I'll be a Cheltenham this weekend, but do pass High Wycombe regularly might like to arrange to say hello one time if ok

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Formerly JJH

I learn more from my mistakes than my successes

John,

You are welcome to drop in and see me anytime. Drop me a pm and we can arrange something.

The reason I asked about the string gauge is that reading your original question, the design for your guitar seemed to come from there as the focal point - to paraphrase "I play heavy strings so the top needs to cope with it". With shop bought instruments that you have described with thick unresponsive tops - fair enough - but as you are now making your own instrument you can control responsiveness and the string gauge should be determined by the top/guitar you are going to make.

I was fishing to see if it was your playing style (as opposed to making the top respond) that was your issue with needing heavy strings and would then have suggested making shorter scale instruments. Anyway we can talk all this through if/when you came and visit.

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Dave White
De Faoite Stringed Instruments
". . . the one thing a machine just can't do is give you character and personalities and sometimes that comes with flaws, but it always comes with humanity" Monty Don talking about hand weaving, "Mastercrafts", Weaving, BBC March 2010

Personally I was wondering about top radius myself lately - initially I was gonna build an OM size guitar and I decided on a 25/15 radius scheme top and back respectively.
(because it seemed to be the most popular)
Now Ive changed my mind, and decided to build a parlour.....
Im underway on the project - Im to the bracing stage and was wondering if the 25/15 radius arrangement was still the best way to go on a smaller guitar??
I see in the plans the top is flat and Im wondering if that might not be the best way to go - Mabye someone here can offer some opinion on how I should proceed?
Should I build 25/15 or something different?
Thanks in advance you guys!
Cheers
Charlie

I built a size 5 parlor with the exact same 15 / 25 combo that I do on my larger guitars. Even though the plans called for a flat top. Adjustable neck as well.

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Allen R. McFarlen
Barron River Guitars & Ukuleles
Facebook
Cairns, Australia

amcfarlen
How did it work out, and more importantly >sound?
I mean I was certain it "could" be done, and it obviously has -
but more to the point was it prudent?
Have you been able to compare it against the sound of any flattop parlours? - stuff like that?
If it was made for a customer - were they absolutely satisfied with it?
Cheers
Charlie