2 What is sound recording?

In recent years, digital technology has given us possibilities that were unimaginable just 10 years ago. The development of digital technology has indeed brought about recording possibilities that were previously inconceivable. The transition from analog to digital technology has made it easier for more people to experience the excitement and satisfaction of recording. In the past, people typically needed expensive equipment, filling an entire room or recording studio, to create high-quality recordings. Now, the new generation of smaller and more affordable recording devices can be placed in a corner of a bedroom or the backseat of a car. This allows more musicians and recording engineers to participate in the recording process.

A recording engineer should be an excellent performer. Their skill lies in helping artists achieve their sonic imagination. Whether it’s capturing the shimmering overtones of a string quartet or the energetic impact of a blues electric band, the recording engineer uses microphones to capture the liveliness of the performance. The post-production work in the recording studio, such as adding effects and adjusting levels, organizes and blends the raw audio material into a beautiful musical result. Mastering techniques utilize audio tools to make the music more polished, ultimately creating exciting recordings that are loved by clients and bring a genuine sense of pride and accomplishment.

2.1Types of Recording

Currently, there are roughly six methods of music recording:

Live stereo recording: Placing microphones to capture the live stereo effect of a musical performance in real-time.
Live mixing: Simultaneously recording multiple sources and mixing them during the recording process.
Recording with multitrack recorders and mixing consoles: Using multiple recording channels and a mixing console to record and blend audio.
Standalone Digital Audio Workstation (DAW) recording: Using dedicated digital audio workstation devices to record and edit audio.
Computer DAW recording: Using software tools on a computer for audio recording and editing.
MIDI (Musical Instrument Digital Interface) sequencer: Using MIDI technology to record and edit musical notes and instructions instead of directly recording sound.

These methods offer different approaches to recording, making the music production process more flexible and diverse.

2.2.1 Live Stereo Recording

This method is most commonly used for recording orchestras, symphony orchestras, organs, small choirs, quartets, or solo performances. Microphones are used to capture the integrated sound of instruments and the acoustic characteristics of concert halls. Additionally, with minimal microphone techniques, this method can also be used to record folk bands, acoustic jazz bands, or classical music choirs in a well-constructed indoor space.

Draw a recording cascade diagram for this recording method. Let’s analyze each stage from left to right

*Recording Path for Live Stereo Recording*

Instruments or vocals generate sound waves.
Sound waves propagate through the air and bounce off or reflect from the walls, ceiling, and floor of the concert hall. These reflected sounds contribute to a pleasant sense of space.
The sound waves from the instruments and the room reach the microphone, which converts the sound signal into an electrical signal.
The quality of the sound largely depends on microphone technique, including microphone selection and placement.
The signal from the microphone enters a two-track tape recorder. It can also be recorded on a hard disk recorder, CD-R burner, DVD-R burner, flash-based recorder, or computer hard drive. The signal alters the representation stored on the media, such as the magnetic domain pattern on a hard disk. During playback, these stored representations are converted back into a signal.
During recording, the signal is stored on a track, which is a pathway or channel containing the recorded signal on the media. A single media can record one or multiple tracks. For example, a two-track hard disk recorder can record two tracks on the hard drive, just as in stereo recording where two different audio signals are captured.
To monitor the signal during recording, headphones or a monitoring system such as a stereo amplifier and speakers are required. The monitoring system is used to evaluate the quality of the microphone technique.
The headphones or speakers reproduce the signal as sound. This sound should resemble the original instrument sound. However, the acoustic characteristics of the listening room can affect the perceived sound reproduced by the playback system.

2.1.2 Live-Mix Recording

This method is rarely used except for live broadcasting or recording based on a mixing console. In live multitrack recording, the method involves mixing multiple audio signals using a mixing console and recording the output signal of the console onto a two-track recorder (such as a CD-R, flash memory recorder, or computer hard drive). Each audio signal is close to its own track. The diagram below represents this recording method.

*Recording Path for Live Multitrack Recording*

2.1.3 MultitrackRecorder and Mixer

This is a recording setup where several microphones are connected to a mixing console, which is then connected to a multitrack hard disk recorder. The signal from each microphone is recorded on its respective track, and after the band performance is over, the recording engineer mixes these recorded signals. It is also possible to record different instrument groups on each track. The diagram below illustrates this recording method.

*Recording Path for Multitrack Recording*

Each microphone is placed right next to each instrument.
All microphones are connected to a larger mixing console, which serves as the central control unit. During multitrack recording, the mixing console amplifies the weak microphone signals to the level required by the recording machine. The console also sends each microphone signal to the desired track.
The amplified microphone signals are recorded onto the multitrack recorder. Unused tracks can be used to record additional instrument sounds through overdubbing. With headphones on, the performers listen to the previously recorded tracks and play or sing along with them. At this point, the performance is recorded onto an unused track.
After recording is complete, all tracks can be played back through the mixing console, and the desired balance of these tracks can be achieved during mixing. The following are the steps for mixing:
1. Playback the multitrack recording of the song multiple times, adjusting the volume and sound quality controls for each track until you are satisfied. Effects can be added to enhance the sound quality, such as echo, reverb, and compression. These effects can be obtained from signal processors connected to the mixing console or from software applications (plug-ins) within the recording software.
2. Record the final stereo mix onto the computer’s hard drive or output it to an external device, such as a two-track recorder like an analog tape recorder.

2.1.4 Stand-aloneDAW(Recorder-Mixer)

This is a combination of a multitrack recorder and a mixing console in a portable rack. Compared to separate components, this combination is more convenient to use. The recording media can be a hard disk or a flash memory card. Other names for this combination of recorder and mixing console include “standalone digital audio workstation,” “digital multitrack recorder,” “personal digital recording studio,” or “portable recording studio.” Most recorder-mixing console units have built-in effects. Figure shows an example of a recorder-mixing console.

2.1.5 Computer DAW Recording

This is a low-cost recording system that includes a computer, recording software, and a sound card or a set of audio interfaces for capturing and transmitting audio signals to the computer. It allows sound to be recorded onto the computer’s hard drive.

Using recording software, you can perform the following operations:

Record music onto the computer’s hard disk.
Edit audio tracks to trim mistakes, remove unwanted material, or duplicate/cut certain sections of the song.
Use a mouse or controller to adjust virtual control elements on the computer screen and mix the audio tracks.
You can also compose a song by combining musical note samples or loops. Samples are recordings of individual notes from various instruments, while loops are repeated musical segments.

2.1.6 MIDI Sequencing

This recording method involves performers playing on MIDI controllers such as keyboard or drum machines. The controller outputs MIDI signals, which are a series of numbers indicating which keys were pressed and when. The MIDI signals are recorded into the computer’s memory through a sequencer, either a standalone hardware device or a sequencer program within the computer. When playing back the MIDI sequence, it triggers sound from a synthesizer or sound module. The synthesizer can be hardware-based or software-based (such as a “software synthesizer” or “virtual instrument”). MIDI sequences can also trigger digital recordings of real instrument performances, known as samples.

Similar to an automated player piano, MIDI sequences simply record the performer’s gestures rather than the audio signal. MIDI/digital audio software can record MIDI sequences and digital audio onto the hard disk. Initially, the MIDI sequences of a few tracks are recorded onto the hard disk, and then audio tracks (such as vocals, saxophone solos, or any other instrument) are added, all of which will stay in sync.

2.2 Advantages and Disadvantages of Various Recording Methods

Live stereo recording is simple, cost-effective, and quick. However, when recording rock music, the recorded sound often tends to be muddy, and it is often necessary to adjust the balance by moving the musicians’ positions. When recording classical music, certain ethnic music, or acoustic jazz, this method can still yield satisfactory results.

Live mixing is relatively simple and quick. However, due to the “leakage” of sound from loud instruments into other microphones, it can create a distant sound in the recorded work. Additionally, it is not possible to correct mistakes during mixing or performance unless a re-mixing is done. Furthermore, it is challenging to monitor the live sound of the band clearly.

Multitrack recording has many advantages. It allows for the insertion of new sections to modify incorrect musical phrases, covering up the mistakes with correct passages, and layering multiple instruments. This reduces “leakage” and achieves a tight sound. Of course, it is also possible to schedule a separate time for mixing after all the performances are completed and then listen to the mix in a quiet environment. However, this method is more complex and expensive compared to live mixing.

If separate multitrack recorders and mixing consoles are used, each device can be operated independently. For example, the mixing console can be used solely for sound reinforcement, or if a mixing console is already available, an additional recorder needs to be added, along with cables connecting the mixing console to the recorder and external effects processors. This is a reliable and intuitive system for live recording or studio multitrack recording.

Integrated DAW (Digital Audio Workstation) systems installed in a portable single unit box are convenient to use. The unit contains most of the recording equipment, such as a recorder, mixing console, effects processors, and often includes a CD burner. Apart from microphones, instruments, and monitor speakers, it does not require additional cable connections. High-end equipment also allows for music editing. It also features automatic mixing functions, where the storage chips inside the mixing console can remember the settings for mix adjustments, which can be restored during subsequent playback.

Computer-based DAW (Digital Audio Workstation) is not too expensive but offers powerful functionality and easy operation. It can handle complex editing and automatic mixing tasks. DAWs also come with plugin programs (software effects) that can be purchased and installed, allowing for inexpensive upgrades to the recording software. However, computers can crash, and optimizing their settings for audio work can be challenging.

MIDI sequencing allows for the gradual input of musical notes, sometimes even one note at a time, to record musical passages. After completing the MIDI recording, the notes can be edited to correct errors or change the instrument’s timbre or playing speed. With synthesizers, sound modules, and software synthesizers, a wide range of sound modifications can be achieved. However, unless using MIDI/Digital-Audio software to add instrument sounds captured through microphones to the mix, there will be limitations in terms of the original timbre of the instruments.

• Live stereo recording of orchestral music
• Live stereo recording of rock music
• Live mixing – jazz music
• Multitrack recording – pop music
• MIDI sequencing – synthesizer-based folk (early jazz) music (folk music that combines characteristics of jazz, blues, and gospel, characterized by syncopated rhythms and a deep, often repetitive bassline)

2.3 Recordingthe Mixes

No matter which recording method you use, the final step is to mix the music onto a two-track recorder or record the mix as a stereo WAVE file on the hard drive. You can also convert the WAVE file to MP3 or WMA format and then upload it online.

You may want to compile the recorded mix into an album. This can be done using a computer and editing software. You can remove noise, add count-ins between songs, place songs in specific locations, or add a few seconds of silence between songs. All of these tasks can be accomplished using a computer and editing software. The final step is to duplicate the song collection onto a blank CD. This is the final product that can be used for replication or distribution.

Regardless of the recording method used, each step will affect the sound quality of the final product. If any weak link in the process, such as using low-quality microphones, improper microphone placement, or incorrect mixer settings, is present, it can result in a poor-sounding CD. To achieve high-quality recording results, each step needs to be optimized.