The last few days I have had the privilege playing Tim McKnight's very special "Diamond" guitar. It is on a road trip to several people around the country. The guitar is visually stunning with a diamond motif repeated on the neck and body, including the rosette. I generally do not like the look of sound ports but the one on this guitar is beautifully carved reminiscent of a lute rosette. This is the second double top (and double sides and back) guitar I have had the chance to play both share a very even volume on all the strings and frets with no dead notes whatever. Tim's guitar has a deep piano like bass and with the sound port it is one of the loudest guitars I have played from the player's position. It records quite well and I hope I demonstrated that in my recording of "Your Hand In Mine".
http://dcoombsguitar.com/Guitar%20Music/McKnight/YourHandInMine.mp3

Well the guitar, is off to the next person on the road trip so you will soon be hearing more about it.

Rick

For all the construction details I copied from a post Tim wrote earlier:

"Specs:

MiniMac body style, 25.4" scale length, 1-3/4" nut, 2-1/4" bridge spacing, Ebony FB, super-hard gold fret wire, Brazilian RW bridge, figured African Maohogany bindings, gold Gotoh 510s with black buttons, bone fittings and Luckenbooth soundport. The diamonds are matching figured African Mahogany with Pau Abalone diamonds inlayed in the center.

I purchased a luthiers estate several years ago and to my surprise he had dated all of his wood. He had this primo, straight grain, dark, almost black, set of old growth Brazilian RW that he was obviously saving for a special instrument but he never got to use it. He had it dated 1940 so I was entrusted with this Holy Grail set of Brazilian RW which I too had been saving for a special occasion. What better use of it than "The Diamond". My thought was heck if it didn't sound good it sure would look good, right?

The top that was chosen was another special Italian top that I had been saving that was sent to me from a fellow builder in Italy. It is one of those creamy white tops with loads of cross silking medullar rays and distinct "hard" grain lines which is indicative of a super stiff top. The off cuts from the back waist area were saved so that I could make the background for the convergent grain segmented rosette. To stay with the diamond theme I inlayed Pau dots and diamonds in the center of it just to add a little sparkle.

At the 2005 Healdsburg Guitar Festival I attended a "Double Top" presentation given by Charles Fox and Randy Reynolds. They explained the building process that a couple of German luthiers had pioneered a few years previously. Randy had his classical guitar played by Geoff ? of LMI on stage for our listening pleasure. I was seated in the back row of the Merlot Auditorium and as Geoff played the guitar [without any amplification] the guitar was so loud it hurt my ears. It was then that I decided that I HAD to build one of these monsters only in a steel string version.

What a better test mule than the diamond? I was already under the gun to build this magnificent guitar so why not take one more risk? Boy am I gutsy (or stupid) or what??? So I selected another Italian spruce top for the inside, ordered some Nomex honey comb core material and set out to build my first double top guitar. Randy's instructions were rather vague especially when it came to how thick or thin to make the plates and how much or less to brace the top. His white paper hand out was tailored for classical guitars and not steel string guitars so I was taking a lot of risks with this guitar. What it boiled down to was using my intuition and relying on my voicing skills that I had learned from Ervin Somogyi. The center of the X brace ended up being just under 1/4" high which is unheard of in the steel string world. Most X brace intersections are at least twice that high or higher depending on the tone you are trying to get from the guitar.

The finished double top ends up being about 30% lighter than a solid top. The bracing is so shallow that it is almost non existent. What this means for the player is the top ends up being lighter than a Cedar top which allows it to be extremely responsive to a light touch. The Nomex core adds incredible stiffness to the sandwiched top which means that I can use far less bracing mass. The result is a top that can be driven just as hard as Adi without fear of breaking up. I ask Tom Gindorf and Chris Estes to play it as hard as they could at Healdsburg with a flat pic to see if they could get it to break up. Maybe they will chime in … I used a Paudauk & Brazilian RW bridge plate. These two woods are very resonant as well as being hard and wear resistant. The two woods are epoxied together so the grain runs perpendicular to each other. Therefore the bridge plate is less likely to split or crack from the string ball pressure over the years of use and string changes.

The thin sides are two sets of Brazilian RW that are bent together at the same time in my Fox style bender. After they the shape has set over night they are then epoxied together which yields a side set that is extremely stiff and just as light as a single thickness side. Double sides are far less likely to crack if they are accidentally impacted. They are less likely to move around during any environmental or humidity fluctuations and they provide a rigid support structure for the top, back and neck.

The neck and tail blocks are laminated Honduran Mahogany and Sitka Spruce. The blocks are laminated with several layers of thin wood with the grain oriented 90* apart of each layer to reduce wood movement and cracking. The blocks are 40% lighter than the standard end blocks used in most guitars. These are a real pain to make but the end result is worth the extra effort. I learned a valuable lesson when I shipped a guitar with a tapered end pin and a solid Mahogany end block. The UPS gorillas dropped the box and the tapered end pin spit the block, cracked the sides and popped the top and back loose from the end block. It was my mistake because I shipped the guitar with an end pin in it BUT the result was the development of my new crack proof laminated blocks.

The back is my new Hollow Back design which uses two thin back plates separated by a dead air space between the backs. The outer back can be dampened by the players body and yet the inner back is still free to vibrate and couple with the energy from the top. When you look into the sound hole you will not see any back braces but rather a very smooth back surface that reflects the sound like a parabolic microphone."

That sounds very interesting, would love to check that out!