First off, congratulations! That is a very tasty instrument collection in just two guitars! Cherry has its own unique, pretty sound and the SW line of guitars has a lot to like about it.<\/p>\n
The short answer is: \u00a0The simple dovetail neck joint is so named to evoke the image of the traditional dovetail, while actually being Martin\u2019s latest modern neck joint designed as an improvement over their mortise and tenon neck joint, which was introduced in the mid-1990s to bring down production costs of lower-priced Martins and improve their profit margin. And it really is an improved neck joint, both in terms of stability and tone. But it is still a ways short of the tone provided by the traditional hand-carved, hand-fitted dovetail neck joint that has been used since C.F. Martin opened his business in 1833.<\/p>\n
The long answer is of course, longer\u2026<\/p>\n
Technically, all three neck joints are mortise and tenon joints, consisting of a groove or slot called a mortise, which is carved into the side and neck block that sits inside the body, and a protruding tongue or extension of the neck called a tenon, which fits into the mortise. But there are significant differences between the different types of joints.<\/p>\n
The traditional dovetail got its name because the shape of the mortise and tenon are in a wide V, suggesting the tail of a bird. The carving and setting of the dovetail neck joint is far and away the most time consuming part of making a Martin guitar. It is therefore the most expensive task, as it requires highly-skilled craftspeople who are paid the highest factory wages. Only the abalone inlay on the fancier Martins cost more in terms of man hours and materiel.<\/p>\n
When done properly, as they do at Martin, a guitar with a dovetail neck joint can be strung up in perfect pitch, without any glue in the joint. The glue is there to make sure it stays at the proper angle.<\/p>\n
The down side of the dovetail is, any adjustments made to the neck beyond what the truss rod affords, require an expensive neck reset, where the dovetail neck joint is reshaped and refitted. If one hasn\u2019t a warranty on their guitar, they would be lucky to find a repairman who charges less than $600 for this service, and the wait time is measured in weeks \u2013 or months if you want it done at the factory. Non-dovetail neck joints can often be reset in less than an hour, at significantly less cost.<\/p>\n
The upside of the traditional dovetail neck joint is heard in the voice of the guitar. The wide V mortise and large tenon provide ample connection and mass for the transference of energy between the neck and the body. Dovetail neck guitars like traditional Martins have greater resonance than those made with non-dovetail necks, or at least it is a different kind of resonance. It has more waver and wide-ranging presence in the undertone and overtones, and most important to my ear, fundamental notes of greater \u201cviolin-like purity.\u201d This is most noticeable in the treble strings. While some guitar makers manage to get that level of purity in a non-dovetail guitar design, Martin\u2019s M&T isn\u2019t one of them.<\/p>\n
The M&T neck joint is based on a design originally developed in the 1970s by luthier Michael Gurian, which has a slender non-V shape to the mortise and tenon. The Martin version consists of a neck block of laminated wood, which has a rectangular shape for the mortise and tenon, and it is held in place with the help of a bolt. Martin always said the bolt was there simply until the glue dried, but they do not remove it. It requires less time and less skill, but also requires two extra braces, known at Martin as A-frame bracing, which help stabilize the fingerboard extension and neck. All non-dovetail Martins have A-frame bracing of one type or another, with names like \u201cHybrid\u201d and \u201c1-Style\u201d, etc. Basically the M&T was a way of keeping with a wooden neck joint, and not going to a true bolt-on neck, like those used by Taylor, Bourgeois, Collings and several other modern manufacturers.<\/p>\n
The M&T Martins with their laminated neck block proved to be more difficult to reset than other non-dovetail guitars. One famous New York City repairman was laboring over a D-16 when he referred to Martin\u2019s M&T as \u201cNot a true bolt-on, not a true mortise and tenon, but the worst of both.\u201d<\/p>\n
When it comes to tone production, the M&T Martins still sound more like Martins than they do Taylors or Huss and Daltons. After all, they ARE Martins. But they do not sound exactly the same as dovetail Martins.<\/p>\n
M&T Martins provide a great deal of volume and vibrancy, which is one reason people who like the sound of bolt-on neck guitars often prefer the Martins made with the M&T. But they have a detectable raspy quality to the wound strings, and an edge of brashness or distortion out on the highest edge of the trebles, although this is really only heard when playing the guitar with a very heavy attack. Played lightly and they sound very pretty. And those guitars made with mahogany tops seem to filter out the worst of the M&T harshness, like the 15 Series, which offer a LOT of guitar for the money.<\/p>\n
In any case, I am talking about rather subtle stuff, not huge differences. Still, when a player forks out the extra dough required to get a Martin made with all solid woods and a traditional, hand-fitted dovetail neck joint, they are getting their money\u2019s worth.<\/p>\n
The M&T Martins also have less in the way of an undertone cushion, so the fundamental notes stand up and out, overtop of the resonance underneath them, and both the top notes and resonance do not shift or quiver nearly as much as heard in a dovetail Martin. This is why some guitarists feel the bolt-on necks are superior; the fundamental notes stay straight, ring clear and do not waver into each other\u2019s air space, as it were. The dovetail neck notes quaver all over the place and the top notes go a little bit sharp or flat while resonating. But that \u201cimperfect\u201d wavering in the voice is also why some people prefer the sound of traditional Martins, like me for instance. There is a certain richness to that dovetail sound I do not hear elsewhere, and the little imperfections in the warble make each guitar that much more unique. Other guitars with the traditional dovetail include those made by Santa Cruz, Gibson, and many small-shop luthiers.<\/p>\n
Also, with a traditional dovetail, that undertone intrudes more into the top voice of the fundamental notes off the strings, so they marry, more or less, with an undertone that swells up to cushion or surround the top notes, depending on the type of spruce, the species of tonewood used for the back and sides, and the type of bracing.<\/p>\n
For example, Indian rosewood with an Italian spruce top and scalloped forward shifted braces is going to provide a more-obvious example of that undertone swell glowing up and around the top notes than Adirondack spruce backed by maple. To my ear you get even more of that sort of thing from a Santa Cruz than a Martin. And not that this does not happen with non-dovetail guitars. It just does not happen as much, and in the case of something like a Collings it happens virtually not at all, as the fundamentals stay very straight and pure and stand apart from each other, and from the resonating glow below them.<\/p>\n
One notable aspect in favor of the M&T neck joint is found in the fact they tend to work very well with electric amplification. That extra presence and somewhat erratic wavering in the undertone and sustaining fundamentals of traditional Martins makes them prone to feedback when amplified through microphones or on-board pickups. The M&T Martins, with their straightaway top notes and more reserved undertone do not overload frequencies in the same manner and require less in the way of EQ, notch filtering, etc. It allows for a more plug-and-play experience on stage.<\/p>\n
The simple dovetail is Martin’s official term for the improved M&T style neck. Basically it too is considerably narrower than the dovetail, but it does splay out more toward a V shape when you look at the mortise and tenon, which provides more contact surface. And when looking at the joint from above, when it is in place but the fingerboard is removed, it looks like a bow tie, made up of two small dovetails, one with the flat edge near the body, the other near the neck, and their points touching at the center. This insures a more secure connection with the neck block. And to my ears it has proven to provide superior transference of resonant energy compared to the M&T neck. There is just more presence and power and greater resonance in the voice.<\/p>\n
Before assembling the guitars with the new neck joint, the simple dovetail is refined by a new robot at Martin which is pretty cool to watch, as it uses lasers to measure the minutest differences in the shape of the slot and the tongue, and then it cuts them so each guitar has a neck and block that are perfectly fitted for one another. While it is not made by a carpenter patiently using hand tools to coax a dovetail neck joint into perfect alignment, it is a lot faster, which allows for a lower priced guitar, and the simple dovetail provides a noticeable improvement in the subtle tonal properties, when compared to the M&T neck joint.<\/p>\n
None of this is to say the M&T Martins are “bad guitars.” To anyone who has played the OMJM John Mayer model, or the D-16 Large Sound Hole model from the M&T era, it is clear they are still professional level guitars. But now that both of these models are being made with the simple dovetail, I will venture to suggest they sound even better.<\/p>\n
The bottom line is, overall the guitars made with the simple dovetail sound noticeably better than the M&T.<\/p>\n