Part 1: Microphones
If you want to break out of the box and get great recordings of real instruments, we have the ultimate guide to recording anything and everything. In this part 1, we kick it off with the tools you need to capture the perfect sound in the first place: microphones.
Working in the box is many people’s preferred platform of choice for music-making these days, for understandable reasons. It’s so easy to do everything in one place on your desktop. You can use sampled audio for pretty much everything plus a range of quality plugins. But recording vocals, acoustic and electric instruments from the outside world is also a lot easier to do now. This is thanks to a vast number of cheap, good-quality microphones and audio interfaces.
The microphone is the very start of the recording chain. So in this first part of The Ultimate Guide To Recording, we’ll cover different microphone types and what they are best at recording. We’ll also be discussing polar patterns and some of the tech terms you’ll come across when buying mics.
In the second part of this feature, we’ll focus on the best ways to record every instrument, from voice to piano, electric guitar to violin, breaking it down into simple and practical techniques. For now though, let’s focus on the main recording tool: the microphone.
The signal chain
From microphone to monitor, that’s your audio signal chain. The microphone is the first and some would say the most important part of it. Capture a great quality instrument recording – that being from orchestra, band, or voice – and you can worry less about processing later.
Considering that microphones and studio monitors are at the start and finish of the recording chain, it’s perhaps apt, if not obvious, that they both tend to employ similar technology to get that sound in… and back out again. A diaphragm in the mic records the vibration of sound and a diaphragm in the speaker delivers it back again.
There are two main types of microphones plus at least two lesser categories that we’ll cover later. The main ones, though, are dynamic and condenser mics. Dynamic microphones are based on that diaphragm idea we just mentioned, broadly all using a wire coil, magnet and diaphragm. Audio vibrates the diaphragm to move the coil which generates a current – sound in electric form.
Dynamic mics are your bread and butter mics, utilizing this classic design, and are often cheap. They also require no external power. They are great at capturing ‘big’ sounds so are often employed as live microphones or on amplifiers with electric instruments. (But like most subjects, rules in the mic arena can be broken!)
Condenser mics are, again broadly speaking, far more sensitive, and are designed to capture more detail than dynamics. Two plates act like an electrical capacitor that stores charge; one is fixed and the other moves to generate fluctuating charge to record different levels of audio.
Because condensers use an electric charge, they require power from a battery or phantom power by way of your interface. Use condensers (generally) for acoustic instruments, delicate percussion, and more intricate recording situations where detail is paramount.
Other cool mic types
You should also consider other microphone types from smaller but growing sectors of the market. Think of ribbon mics as much more sensitive dynamics. They use a very thin, electrically conductive film – or ribbon – placed between two magnets. Again the current is generated from the physical movement of the ribbon. But it’s way more sensitive than the diaphragm in a dynamic, so ribbons capture much more detail. Use them for vocals, instruments but not, perhaps, live or amplified instruments. Their disadvantage is cost and fragility although both of these factors have improved in recent years.
Finally, we have the newer mic options for our digital world with both Bluetooth and USB microphones. These offer good recording options for direct connection (or not in Bluetooth’s case!) to your phone, tablet, or laptop. They are low in cost and have easy connectivity as they don’t require the preamps of your interface. They are great options for general recording tasks and are improving in quality all the time.
Before we cover some technical mic terms, we should detail microphone ‘patterns’ such as cardioid, omni, and multi. These refer to the polar pattern of a mic, the area around it that is best employed when recording.
Omni-directional microphones are good general solutions. They record sound equally well around the microphone’s grill as the pattern is effectively a circle. Better still think of it as a ball sitting on the end of your microphone. These mics tend to work best at whatever you point them at so are. Dynamic cardioids especially, like the Shure SM range, are the ultimate low-cost mic and amplifier mic specialists.
Bi-directional or figure-of-8 mics can focus on two opposite areas. These are great for recording a couple of instruments or a single instrument with some room ambiance.
Other polar patterns include Supercardioid and Hypercardioid which simply place the emphasis on slightly different areas. These can be great for more detailed and focussed recordings, depending on the environment in which you are working. Finally, multi-pattern mics have switches that allow you to select different pattern shapes.
And now, the specs
The Frequency Response quoted on a microphone is, as you might expect, where its best capture range lies. Obviously, the wider the better – human hearing covers 20Hz to 20kHz. That said, some mics deliberately focus on certain ranges to capture particular instruments (parts of a drum kit, for example).
Sound Pressure Level (SPL) is essentially the loudest sound that a mic can deal with. It might be quoted as 120dbSPL – a decent level. The higher you go, the bigger a signal a mic can handle before distortion kicks in.
The signal-to-noise ratio is the level of the audio signal you want to be pitted against the noise you obviously don’t want to hear. The higher the better here – a stronger signal versus the inevitable noise floor. Look for bigger levels, ideally 70dB or more.
Finally, there’s the noise generated by the mic itself. Self-noise is the inevitable hiss you get from the current moving around the circuits or air particles around the diaphragm. Here you want a low figure – less than 25dBA.
That’s our general and super-quick overview of the microphone, the start of our Ultimate Guide To Recording Everything. Next time we’ll look in more detail at mic placement for recording a range of instruments.