12. The Recording Chain

12. The Recording Chain

We have looked at the way microphones work in some detail, and sat in on a typical recording session. Now it’s time to see what electronics and processes the music is going to go through as it travels its way to the listener.

Most recording is done with the performers in a studio and the engineer and his equipment in a separate control room. A separate control room is essential because it is not possible to obtain an accurate sense of what is being recorded when you are in the same room as the performers. We will discuss the control room environment in the future, but for now we are looking at the equipment involved.

Microphone Preamplifiers

Once the electrical version of the sound leaves the microphone, it travels through cables and connectors before it reaches an amplifier. This amplifier is called a preamplifier for historic reasons since it preceded a power amplifier in a PA system. It is specifically designed to be used with microphones and nothing else. It is a critical element in the recording process because any quality loss at this stage cannot be recovered later.

Traditionally, the mic preamp was incorporated into the large mixing consoles like you see in photos of recording control rooms. The console was the nerve center of the CR and amplified, modified, routed, and mixed the audio. In recent years, however, there has been a trend away from large (and incredibly expensive) consoles to a new paradigm that uses a different approach. Today “outboard” mic preamps are the norm, and there are many manufacturers making this critical component of the recording process. The mixing console is replaced by a computer work station.

The mic preamp may use solid-state devices or it may use vacuum tubes. Personally, I have abandoned all solid-state mic preamps and use vacuum tube preamps exclusively because they just sound better to me. They sound musical. But other engineers and producers make excellent recordings with solid-state preamps. It’s a matter of style.

The mic preamp boosts the very low-level output of the microphone to what is termed “line level,” which in the pro audio world is about 15dB higher than line level in the consumer world. Also, in pro audio, all signals travel on balanced cables, meaning that there are two conductors carrying the audio signal as opposed to one conductor and a shield used in an unbalanced system (consumer). Balanced lines offer many advantages, at a monetary cost, compared to unbalanced cables.

The Recorder

Through the history of recorded music, the actual recorder has evolved from the wax cylinder to the lacquer disc to magnetic tape, and since the 1990s, a digital signal recorded on a computer hard disc.

Most music today is recorded using a software-hardware combination of a digital audio workstation (DAW) and a computer. (There are also systems that use a dedicated, proprietary, embedded computer, but the typical Mac, Linux, or Windows computer is more common.) The DAW emulates in software the functions of the large recording console, and often has additional features that can only be done in software.

This DAW/Computer recording approach has opened up the world of recording to many people who could not afford the $250,000+ cost of an equivalent console and multitrack tape recorder. Now, for less than $5000 anyone can have world-class recording capability (other required equipment like microphones and monitor speakers are additional). Even the largest studios now record with a DAW, sometimes in conjunction with their impressive-looking console.

Digital recorders have a wide variety of formats and resolutions available. The decision of what to use is left to the engineer, keeping in mind where the music is going and whether it is transitory or will be permanently archived. We will study the recording formats in detail in a future installment.

Monitor System

Essentially, in the simplest recording system, all we need is a way to amplify and route our audio to a recorder. But we can’t work without hearing what we are doing, so a monitor system is required. This is almost always loudspeakers, but some growing percentage of recordings utilize headphones, since many listeners are going to hear the music that way. But every studio has loudspeakers for monitoring, if for no other reason than there are often many people who need to hear.

Monitor speakers are often like home speakers, but they usually are designed specifically for the control room environment. That means they not only have to deliver the highest quality reproduction, but they also have to be capable of realistically loud output, and they have to be very rugged since the recording environment has occasional “surprises” when the audio level vastly exceeds the normal volume. (Someone banging into a microphone, for example.)

For many decades, the monitor speakers were large, using big woofers (15-inch was standard, sometimes two of them), and horn tweeters. Today, many engineers and producers prefer smaller speakers, often similar to what are used by audiophiles. There is some overlap in the two worlds when it comes to speakers.

Most studios have several speaker systems that can be used to obtain different perspectives on the sound. There might be a legacy huge system, a smaller but high-quality modern speaker system, and then a system that might be typical in a low-end home stereo system. It’s also important that the recording translate well for people listening on laptop speakers, or typical computer speakers. Many engineers also check their recording using ear buds, which is how many people listen to music.

Why all that? To make sure that the recording translates well in all circumstances. That involves compromises in the recording released to the public and we will talk about that when we cover the mixing and mastering process.

Processing Equipment

The mics, preamps, DAW, recorder, and speakers are the core elements in recording, but that would suffice only for the simplest sessions. Since the 1960s, additional enhancements have been used in the majority of recordings.

These include artificial reverberation, equalization, compression, and many other tools that the engineer and producer have to achieve their artistic goal. Digital devices and software are available to emulate effects that were invented using hardware circuitry, and digital allows us to create new effects that would not be possible in hardware.

Next: We will continue to explore the world of audio processing and the audio chain.