If your strings are where the sound originates, your guitar pick is what sets those strings in motion. It stands to reason, then, that guitar picks of different styles and materials act slightly differently upon those strings and elicit different sounds as a result.
Here are the three main factors influencing guitar picks:
Gauge (thickness): Most players’ first consideration, the thickness of the pick determines the playing feel — whether it feels firm against the strings when you strum, has a little give, or is somewhere in between. Thickness also plays a big part in how a pick sounds:
The thicker the pick, the more energy goes into the string when you pluck it, rather than dissipating in the bending of the pick, resulting in a louder, bolder, firmer tone. Thinner picks sound softer, lighter, and janglier.
Shape: More precisely, the shape of the picking edge (often a corner, of sorts) plays a big role in forming the timber of the note. A sharp or pointed picking edge presents more clarity and elicits a brighter tone with more harmonic overtones. A wider, more rounded edge blurs the higher-harmonic content ever so slightly, emphasizing lows and mids and giving you a warmer tone.
Many picks have both types of edges in one — the front edge and the two back corners — so you can swap these characteristics without even changing picks.
Material: Naturally, the stuff that a pick is made from influences its rigidity, but even beyond that, different materials often sound different, even when in two picks of the same shape, thickness, and flexibility.
Different types of standard plastic and nylon picks can even sound considerably different, but there are several makers out there (explore V-Picks, BlueChip Picks, and Red Bear Trading) that have won many devoted players for their use of original and supposedly tone-enhancing materials.
The cool thing is about all this pick talk is that you can easily try a wide variety of picks for just an outlay of a few bucks (or maybe a couple dozen bucks if you go for some of the more advanced-technology picks available today). Even at the higher end of the pick price range, this is one of the easiest and most affordable ways to modify your sound.
And then there’s the sound of no pick at all. What’s the sound of one hand clapping? Mostly a barely audible swoosh-swoosh-swoosh. The sound of playing the guitar without a pick, on the other hand — using just your bare fingers — can be extremely pleasing, effective, and musical, and is certainly worth trying after you get the hang of it.
Using bare fingers generally elicits a warmer, rounder tone from your strings, but also one that is often extremely dynamic, and with some extra snap and pop if you grab the strings slightly when plying (or vary your attack throughout). Adding some fingernail edge to the bare fingertips gives you a hybrid sound somewhere between flesh and pick.