For an example of how every musical community has its own qualifications for great sound, consider the guitar. Deeply rooted in culture and history, the guitar sets its standards by the legendary players of classical, jazz and rock and roll. Those are three very distinct sounds all from one instrument, and every one would be considered great. You can find similar examples with other musicians, from wind players to vocalists. Naturally, the same also applies to percussion keyboard instruments. Keeping one's own sound and the culturally-defined "conceptual model" in mind is particularly crucial to percussion ensembles, considering that any given performance can potentially cross into many musical genres. A lighter, brighter tone would be appropriate for rags, whereas Guatemalan marimba is better suited to a more wooden sound. In Western art music, a whole range of diverse acoustics can be included.
Whatever the intended sound, it all starts out as an acoustic picture in the performer's mind. From there, practiced physical motions work together with instruments to translate the mental image into real-world sound. When you play keyboard percussion, complexities like striking location and acoustic setting are also factors—what it boils down to is that creating great sound is a matter of precision, technique and using mallets that are well-suited to your musical style and surroundings.
It is important not to underestimate the effect that mallets have on your percussion keyboard sound. Differences in weight, mass and firmness compound on each other to make every type of mallet unique. For instance, the head of the mallet is limited in hardness only by what the instrument can physically withstand, and in softness only by the point at which it would become inaudible. Naturally, the venue in which you are playing is directly related to this, since the acoustics of a space will affect the way we perceive articulation. As an example, consider a 2000-seat auditorium in a large concert hall. A venue like this has a large amount of space for sound to proliferate and reverberate, which has a softening effect to the audience. For that reason, it requires a somewhat harder mallet than what you might be used to using during practice in a much smaller space. On the other hand, when you play in even smaller or drier places like recording studios, a softer mallet could be called-for. To provide a practical case: a marimba piece that sounds right with IP240s in a mid-sized rehearsal space may take IP300s in the concert hall or IP200s in the recording studio. This adaptation becomes even more important the lower the register used for the piece.
The impact of mallet weight on your keyboard instrument's sound is relatively similar to other percussion and their respective striking tools. Weightier mallets will generally yield a darker and mellower tone, while lighter mallets sound more lively and bright. This effect occurs because mallets with a greater weight will introduce more pronounced frequencies of sound in the fundamental and lower partials. The opposite is the case with lighter mallets, which favor the upper partials, resulting in a sound that is brighter overall.
Apart from the relationship between the weight, mass and hardness of the mallet, many percussionists also consider the choice of shaft material to be an important factor. Today's most common materials for percussion mallets are rattan and birch. As with many things in music, the preference here is subjective. Some consider the feel and tone of rattan to be superior, particularly when used for two-mallet techniques. Rattan does have a drawback in the form of greater flexibility than birch, however, and mallets with rattan shafts are often made shorter. For these reasons, you may find birch to be a better choice for four-mallet playing if you use the Stevens' grip or any other handhold that means positioning your hands at the very end of the mallet shaft. A longer and more rigid birch mallet will allow you to reach very wide intervals that would be out of the rattan mallet's range. Even two-mallet players may prefer the tighter feel of birch—it's entirely a matter of taste.
A mallet's "presence" is one further characteristic that has implications in how your keyboard percussion will sound. This measure describes the capability of the mallet to make the instrument project its sound. If you have ever watched a player perform with a mallet that appeared to be the correct hardness but simply wasn't clearly projecting, presence was probably the issue. Conversely, you could also see the opposite effect: for example, a marimba chorale whose intended arco effect is undermined by an excess of clarity. Common sense tells us that weight is a contributing factor to a mallet's presence; another factor, specific to wrapped mallets, is the specific material surrounding the core. The tightness of its winding also plays a significant role.
Wrapped mallets are most often made with either cord or yarn. For examples of different wrapping methods, we will look at various mallets by Innovative Percussion. Mallets like the Ford Series, to start, are wrapped fairly loosely with soft yarn. This results in a low presence, which is suitable for very soft parts. The sound made by the 801s and 802s could easily be compared to the human voice, while the 803s and 804s are more brilliant, akin to a harp. Turning the weight and presence up a notch takes you to the Soloist Series, which are versatile mallets that make a good all-around choice for percussionists on a budget. You can use IP240s for virtually anything. The next IP example would be the Moersch Series, which have a wonderfully rich character and use an acrylic-style core. This creates an effect similar to a wind instrument, where sound increases in brightness proportionally with volume. They're also heavy enough to project to every corner of a good-sized hall. The Rosauro Series, in comparison to the Moersch, are more tightly yarn-wrapped but a bit lighter also. The result is a bit of a thinner sound that retains great projection. The articulate nature of these mallets makes them ideal for musical styles like jazz, pop and world music. For those times when you need extraordinary projection and clarity, mallets like the IP Ensemble Series 260 and 360 deliver good results. They lend themselves well to vibraphones as well as to a "Bethancourt" marimba sound.
In many cases, mallets are labelled as being for the vibraphone or marimba specifically. While there is some value in these designations, it's even more important to focus on how the mallets actually sound. Often times, a mallet described as a vibe mallet turns out to sound excellent on the xylophone, marimba, chimes and almglocken as well. You'll find that the same is true of many yarn-wrapped marimba mallets. Above any label, your primary concern should be the sort of sound that you're looking for. Having said that, IP's Rattan Series 201, 391 and 251s do render a highly traditional vibraphone sound. Their weight and hardness are relatively standard, and they encourage mallet dampening with mushroom-shaped heads. For younger musicians who need an affordable set of mallets, the RS 301s are a solid option. To achieve a darker sound without losing projection, look into mallets similar to the IP Casella Series 1004, 1005 and 1006.
If you are a xylophonist, consider the James Ross Series as good examples of the sort of mallet you might seek to try out. These can deliver a wide range of sounds, from the full and rich tones of the heavier 904s to the piercing, brittle and almost metallic sound of the much lighter and harder 905s. For something similar to the 904s but a bit brighter, the 906s work well. There are also the 902s for a classic ragtime sound, ideal for moderate ensemble scores and highly dynamic passages. At the heavier end of the James Ross series are the very rich and lower-articulated 901s and 903s. These mallets, and others like them, can also be used with crotales and bells. If you are limiting yourself to just one pair, then you should use the 904s or 902s as your benchmark depending on whether you want a darker or lighter sound.