Here’s a sight anyone who’s ever sung in a band will be very familiar with, I’m sure.
I wonder if Shure had any inkling of how successful the SM58 would become when it was first launched in the 1960’s. Whether they did or not, since that time the SM58 has become the single most popular and commonly used microphone all over the globe. They are instantly recognisable by almost anyone; if you’ve watched MTV or Top of the Pops, been to Glastonbury or seen a live gig the you’ll know what a ’58 looks like.
Clearly there must be a reason that they became so widespread, setting aside the fact that it just “sounds good” which plenty of other mics do too:
To say that SM58’s are tough as far as microphones go would be an understatement. They’re tough as far as almost anything electrical goes. I’ve seen them dropped off stages, trodden on, covered in beer, hurled into the ground by ‘passionate’ singers, hit with drumsticks and even driven over! Despite all of that abuse, they just keep working simply because they are robust and there’s not really much to go wrong with them. That fact alone has made them a popular investment for amateur musicians and live-sound crews alike who need something that is reliable and will tolerate falling off mic stands. However don’t let that fool you into thinking they are unsophiticated, which brings us neatly to point 2.
The response pattern of an SM58 is described as ‘cardioid’, and is actually very directional. When you record something like the singer of a live rock band with a ’58, you may be surprised by how much of the ambient noise made by the band and the crowd the mic doesn’t pick up. This is partly due to its response pattern and partly due to the fact that the singer is very very close to the mic compared to everyone else. With a lot of other mics, being so close would just overload the microphone and as a result you would have to have it further away and would pick up more ambient noise (or ‘spill’) as a result.
The SM58 can be put so close to a sound source, because it was designed to be able to handle high Sound Pressure Levels (or SPL) without distorting. So not only is the mic durable and directional, but it can be put up really close to almost anything, which makes it very versatile. They can be rigged close to snare drum skins, or even in the sound hole of a kick-drum and they won’t complain. The design of the mic naturally compensates for bass tip-up, where as the mic gets closer to the sound source the amount of low frequency that it picks up increases relative to the mid and high frequencies. In short, this mic was made to be used up close.
4) Dynamic Compression
The other thing that draws professional engineers to theSM58 is its natural dynamic compression. This basically means that when a very loud source exposes the diaphragm to a high sound pressure level, when it moves in one direction the the diaphragm hits the innards of the microphone and then moves no further, and when it moves in the other direction the surround that the diaphragm is mounted on stops it in a similar way. This restriction of movement at high sound levels compresses the waveform that the microphone generates. This is useful not only because it takes a lot to actually distort the microphone, but on something like a snare drum, part of the compression that the engineer might otherwise do, has already been done for them!
Finally, just to prove how indestructible the humble SM58 really is, watch this:
See what I mean?..
[Image via Keith Bloomfield, video via tidningenstudio]