The Pro-Audio Guide For People Who Know Nothing About Pro-Audio Part 1


So…

You’ve done some playing and singing. You’ve written some songs. You’ve got this whole “music” thing down to some degree, and now you’re thinking about gigging or recording.

But you’re bewildered. You don’t know how to get started with the maddening, intimidating, even terrifying pile of hardware and software that gets used in modern production. This series is for you. It should help you understand a little more about what’s going on, so you’re not as mystified.

We’re Going In!

Obviously, what we’re working with is sound – a vibration in something physical that we can hear. Any real dive into the physics of sound is beyond the scope of this series, but you should be aware that all sound:

1) Has an intensity, or amplitude.

2) Has a rate of vibration, or frequency.

Sound has other properties as well, but these two will be the most important for a basic understanding.

Now, then. The fundamental key to all audio production is that we MUST have sound information in the form of electricity. Certain instruments, like synthesizers and sample players don’t produce any actual sound at all; They go straight to producing electricity.

For actual sound, though, we have to perform a conversion, or “transduction.” Transduction, especially input transduction, is THE most important part of audio production. If the conversion from sound to electricity is poor, nothing happening down the line will be able to fully compensate.

Mr. Microphone

Transducers come in various forms, but the most commonly recognized sound-to-electricity transducers are microphones.

Microphones come in a large array of sizes, shapes, and behaviors. They all derive from one of two basic flavors, though:

1) Dynamics, which use wire coils and magnetism to generate current.

2) Condensers, which create a “variable capacitor” to produce current.

You should be aware that there are sub-categories for each basic flavor, such as moving-coil dynamics, dynamic ribbons, “active” dynamics, electret condensers, tube-amplified condensers, and whatever else the industry can cook up. However, in the most common scenarios, what you can keep in mind as a baseline is that dynamic mics don’t fundamentally require a steady supply of electricity to work, whereas condensers do.

Another generalization that can be made is the overall character of the microphone flavors. Although all microphones react quickly by human standards, dynamic microphones have moving parts which tend to be “heavy.” The moving portion of a condenser microphone can have far less mass, which makes for a vibration sensor that can start and stop moving very easily. Condenser mics are a common choice for the transduction of quiet, “delicate,” or “complex” sounds, and condensers can more easily be extremely accurate – but this does not necessarily mean that condensers are correct for what you need to do. There are plenty of dynamic mics which sound very pleasing on a tremendous variety of sound sources, and they tend to be more resistant to accidents and mishandling (although dynamic ribbons can be very fragile indeed).

Microphones also differ from one another in terms of their directionality, or the relative sensitivity of the microphone at different angles around the microphone element. This is also referred to as the “polar pattern,” in reference to how this directionality is commonly plotted on specification sheets. In terms of the basic microphone types, any directionality is possible. There are omnidirectional dynamics and ultra-selective condensers, and the opposite is also true. A list of common polar responses includes:

1) Omnidirectional, which has essentially the same sensitivity at all angles around the element.

2) Figure-Eight, which is sensitive to the front and rear, and tends to reject sound from the sides.

3) Cardioid, which is highly sensitive to the front, somewhat less so at the sides, and has a point of very low sensitivity at the back.

4) Super-Cardioid, which is highly sensitive to the front, less sensitive than a cardioid at the sides (with a particular side angle which is very low sensitivity), and has some sensitivity at the back.

5) Hyper-Cardioid, which is like super-cardioid, but narrower and with a more pronounced “sensitivity bump” for sounds coming from behind.

In many applications, mics with strong directionality are often preferred and even necessary. However, omnidirectional transducers see quite a bit of utilization as well, especially when accuracy is needed or tonal consistency at varying distances is required.

Contact

To close this installment, it’s worth talking about another kind of transducer, the “contact mic.” Contact transducers aren’t really microphones at all, in the sense that they are not designed to work well with sounds in air. Rather, they are intended to be fixed to a vibrating surface, which causes the element to deform or flex and thus create an electrical current. This is a piezoelectric effect, and so these pickups are often referred to as piezos.

Contact transducers generally sound rather artificial when compared with microphones, but most microphones aren’t in direct physical contact with a sound source. At the same time, piezo pickups can be very handy for dealing with certain problems, like instruments which need to be made disproportionately loud with minimal feedback.