Recording studios are performance spaces purpose built for recording, mixing, or mastering audio. The typical recording studio layout features the iconic glass window between rooms, so that the artist and recording studio engineer can see eachother, or so that the soloist or singer can see the band. It serves to allow visual information to pass through, while isolating the audio. This is useful when the audio engineer wants to listen to speakers, but the microphone would otherwise pick up the sound. The glass, and a pair of headphones, allows the artist to go “into the fish-tank” and be isolated from whatever might be happening in the control room.

Windows or Cameras for Eye Contact or Visual Cues

One or more rooms are usually linked with either windows, or a camera system. Typically a live recording room is large enough to accomodate a band, or large choral group. The additional space between instruments, or choral members, can allow for space in the mix later to separate elements out wider into the left and right of the stereo image of the mix. THe artist performs in the vocal booth, or live recording room and the playing is picked up by microphones. For electric instruments like keyboard, or synthesizer, a DI box or “direct box” is used. A DI box uses a small transformer or coil of wire, to convert the electrical signal from the instrument into something usable by a mixer, recording console, or audio interface connected to a computer.

Isolation or Vocal Recording Booths

Isolation booths, or ISO booths, or VOCAL booths are sound insulated rooms with doors to allow the artist to go inside, perform their parts, while the audio engineer does the recording. With his or her help, the artist can record multiple takes, or multiple tracks (known as a multi track recording). The Control room is typically where the audio engineer is, which is connected to the vocal booth or isolation booth. Additional producers, arrangers, composer, or even vocal coaches by by in the control room as well, to give the artist feedback on which takes sounded best, and which ones might need to be redone. It’s hardly ever the first take that sound the best. Vocalists often need time to warm up, and often, a take or two to warm up and get levels of the recording equipment is necessary. The Recording engineer listens back through speakers (sometimes called monitors) to monitor the sound, and manipulate the level or sound of the tracks by using tools like an equalizer (which changes the tone) compressor (which changes the volume), or effects like reverb (which can add echo or ambience).

Typical Soundproofing and Acoustic Considerations

Booths often are smaller than the control room, and are usually just big enough for a few people. The booth is soundproofed to keep external sounds out and whatever sounds generated in. They are designed to have a minimal amount of reflections, which can create unwanted echo or ambience in the track. Acoustic panels, or absorption type materials like foam are often used, but other methods such as angled walls, windows with double thick glass, or walls with double thick drywall, or offset studs and rubber pieces to isolate studs, or floated floors and air gaps or sound insulation between surfaces where we do not want sound transmitted, may be employed. You can make a cheap sound booth by throwing some pillows in a closet and running a cord under the door. Adding carpeting or soft furniture or other absorbing material may help as well. When you are trying to construct a good vocal booth, keeping in mind the density, and sound transmission of the materials used for construction is important. Everyone knows a piece of paper doesn’t do much to stop sound, but a sheet of metal which is much more dense, would stop a lot more. Cheap foam or egg cartons and blankets all have a relatively low density, so they have a relatively low amount of absorption. In addition, the transmission of sound through materials can be avoided by use of an air gap, or de-coupled layers of varying density to absorb the sound.

Dimensions and Geometry of Acoustics

The overall dimensions of the booth play a huge role in the sound too. Avoiding parallel walls which reflect flutter echoes us ofen times used as a strategy. Different ratios of length to width can be more favorable, so looking into the dimensions of a build out can greatly improve the acoustics. Square parallel shapes (such as the floor and ceiling, which are parallel surfaces) will reflect back and forth creating flutter echo. So a very absorbing ceiling, with an air gap between the “cloud” layer and the ceiling is often incorporated into professional recording studio booths.

Ideal Vocal booth Design

If I was designing an ideal vocal booth i would incorporate walls which are not parallel, and a ceiling which is very absorbent. A concrete or brick wall with multiple layers of varying densities, which each layer is not attached with a screw, but rather some sort of slightly resilient, or springy consistency such as rubber, or special sound absorbent adhesive. The floor would be floated on a layer of highly dense material, then a spongy underlayment. A wood floor and elements of wood are generally accepted as sounding good, but up to 80% and 100% of the ceiling should be covered in fabric, rockwool, then wood, or drywall. There are two mathematical numbers which can be used. The Absorption coefficient,. and sound transmission amount. The absorption coefficient is the amount of absorption each material exhibits in a given scenario. The Sound transmission level, is the amount of energy that can go through a merail and exit on the other side., Each of these plays a role in the sound coming in and going out. In addition, the STC and Absorption coefficient can be different for high and low frequencies.

Low Frequencies Carry more energy than High Frequencies and are harder to control

Low frequencies are the hardest to stop. Ever been at a stop light and had a car roll up 3 cars back with bass enough to rattle your teeth? That’s the power of bass. High density and very absorbent materials can deaden bass by a certain amount, but hardly anything except for a vacuum can stop it all together. While egg cartons and cardboard may absorb higher frequencies, the resounding, or resonating low frequencies or midrange can make the sound woody or downright cardboard sounding. Aim for a balanced approach, with many frequencies being able to live in a room, and a stiff, dense barrier to stop them from coming out. Rockwool or mineral wool is by far the easiest material to get ahold of for studio construction, but even material like cotton rags, or high density fiberglass or foam can be used. Rockwool has the highest density and can be purchased in varying densities. In general, the thicker higher density stuff is better. Rockwool is a material that can absorb frequencies as low as 160 hertz (and lower frequeist to a lesser extent) whereas fiberglass, or fabric absorbs almost nothing below 200 hz. Rockwool is an excellent insulator for sound, but its horrible to work with, and has a tendency to get very itchy if exposed to skin, or if particles are exposed to the lungs, a potential hazard to respiratory function. While the fibers are not cancer causing like asbestos. At the very least, gloves and a mask are necessary when working with it. While rockwool is quite stable, usually fabric is put over it to avoid having fibers become airborne or pieces falling off at a later date. is necessary, because it is a very crumbly material.

So where does the sound go? The sound energy actually bounces around and is dissipated into the molecules and creates friction. Since this energy cannot be destroyed or created, it actually dissipates as a barely measurable amount of heat from the friction!

Machine Rooms and other HVAC concerns

There may be different machine rooms, or other rooms within the recording studio where recording equipment is kept. Usually, its a good idea to have the computer or any noisey fans away from the recording area. Things like the furnace, HVAC, or power amplifiers, may create unwanted noise, or guitar amplifiers may be kept in a separate room from the drums to avoid bleed between the micropjomes. THe recording studio itself usually features soundproofing, and sonic insulation between the rooms to prevent sound from leaking between rooms. Recording studios, because they are sealed up well, require specialized heating and cooling equipment. With equipment like mixing board consoles, computers, amplifiers, lighting, and even humans giving off heat, an ultra-quiet furnace, and heating and cooling system that takes into account the needs of the the performers, audio engineers and whoever else is in the studio is important. If you think turning off the AC is doable, it may work, but doing it during the heat and humidity of summer may be a pain, or unbearable. The best types of heating and cooling for studios is passive radiator systems built into the floor. With no fans, and quiet radiant heat in the winter, and cooling in the summer, it keeps the studio at a proper temperature. A dehumidifier or typical wall mount AC system is good enough to keep the humidity within a reasonable range in the summer. Airflow, and the proper temperature for the studio is important. Between 60-73 degrees fahrenheit, and humidity between 40% and 60% are both ideal for humans, and ideal for storage of wooden instruments and recording equipment.

Recording Equipment In the Studio

Recording equipment usually includes microphones, cables, a recording interface, a mixing console, microphone preamplifiers (or pre-amps), outboard analog gear like compressors, expanders, or limiters, and a DAW or digital audio workstation. Although music can be made with tape machines, digital emulation has become much better in the past year, and for the most part, tape machines have become a thing of the past. In addition to the microphones, mixer and recorder, the recording studio requires mic stands and headphones, as well as amplifiers for headphones and speakers, studio monitors, possibly DI boxes, and any instruments or electronic music devices, or acoustic drum kids that may be needed.

Drums

Drum equipment may include wood or metal shell drums, cymbals, and the hardware to hold each drum and cymbal up. Popular brands include Pearl, Gretsch, Rogers, Ludwig, and Premier. Drummers may prefer to use their own cymbals, or snare drum, as well as use their own kick drum pedal. Drums usually include a kick drum, snare drum, floor toms or rack toms, high hat, cymbals, and any other percussion such as tamborine, bongos, congas, shaker, wood block etc.

Keyboards

Keyboard instruments can include pianos such as steinway, organs like Hammond, wurlitzer electric piano , fender rhodes, midi keyboard, or synthesizer, In addition to analog synthesisers and samplers, some keyboards can be plugged into the computer or linked into others with MIDI to tap into almost infinite sounds using the keyboard only for control.

Bass Guitar, Electric Guitar, and Amplifiers.

Bass guitar, and electric guitarists typically bring their own instruments. After all, if you were a race car driver, you’d probably have your own car right?! While what you have might not be the fanciest, or might not be what you wish you had, often times, its the best option for you as a player. You know your weaknesses, and are comfortable with the instrument, and tones you can produce. In other words, its a lot more about the performance than the tools used to accomplish it. On the other hand, many times, recording studios become havens for vintage instrument collectors, including amplifiers, and cabinets like Fender, Marshall, Vox, ampeg, SUNN. Bass and guitar manufacturers like fender, rickenbacker, gibson, Martin, and epiphone all have great instruments that can be used in the studio setting, so often times they are on had at the recording studio. At the very least, contact the audio engineer if you need to borrow an instrument, to ensure that the strings and various adjustments are properly set up. Often times, engineers can recommend the best instrument, or amplifier to get the type of tone your going for, but there isnt one instrument, or amplifier that is the holy grail that is perfect for all situations. Vintage or high end boutique amplifiers or instruments may seem alluring, but often times its the simplest and most tried and true setups that are the most reliable and sound the best. But as far as general advice goes, You almost can’t go wrong with a decent Fender or Gibson instrument for guitar or bass. For bass amplifier, I like Ampeg tube amps with an 8×10 cabinet, and Fender Twin Marshall or VOX guitar combo for guitar. It all comes down to personal preference, so getting that hie marshall tube amplifier may seem to be the answer to your prayers as a rocker, it’s not going to make you good at guitar.

The Recording Studio as an Musical Instrument

The recording studio resonates various frequencies ,and the sound of each room comes into play in every stage. As with any instrument, individual recording studios may have a certain tone, and each room of the studio may house different sounds in a unique way. Artists or producers pay with the ampiece level , and usually try to capture the appropriate level of ambience during recording. Of course, additional reverb or delay can be added artificially, but usually the process involves adding microphones to the room, or placing the microphones near the instruments in such as way as to capture the ideal sound. Modern multi track recording usually incorporates many layers of tracks. A session may have 50 or more tracks, with each element blended together by the audio engineer on a digital audio workstation, but the studio is still a huge factor to music, and while recording on a laptop, tablet, or even phone is possible, not matter what the medium the room will play a factor. Techniques to incorporate natural ambience, and audio signal processing are the audio engineers tricks of the trade, but if your studio stinks, it will likely make your tracks sound like the room they were recorded in. For classical or orchestral recordings, the room plays a huge factor. The symphony or band in essence, plays the room, each instrument inducing frequencies which play off each other, and the materials in the room, hall or church, to hopefully make a pleasing performance for listeners. When recording, the audio engineer is in a way, playing the studio. Following the individual components and recording each tracks into the DAW or tape machine to create a wide variety of frequencies, and levels, to capture an ex itng performance for the listener to enjoy later. This process is consistent with the principles of aocuiscs, and non-musical people, often don’t think about how the process may affect the sound. While some recordngs may strive to capture the true-to-life performance, other recordings may experiment with the realms of impossible or fantastical acoustic scenarios for the listener to exprece. With the invention of computers, sampling, and electronic music, the pre-recorded sound has made a huge impact on how music is made. Nevertheless, the speakers, control room and most importantly the audio engineer’s treatment of the sounds recorded play a large factor in what sort of sound results.

Home studio concerns

The home studio may be smaller, but often times an apartment, hotel room, or spare bedroom is what you have to work with, so making the best of it is essential. In general, small boxy rooms are not as good as medium and larger spaces, with more corners, and less parallel walls is better. Clap your hands, or click together some drumsticks to discover potential issues. Listen carefully for issues like foot traffic, cars, plumbing, or other environmental concerns. Pay particular concern to any air gaps, such as gaps underneath doors, and any heating vents or fans that might need to be avoided. Heat and fans can be a big problem for recordng evnivorents, as well as outside noises. Since recording studios ofen make a lot of noise too, keeping sound out, will also help keep sound in. WHile there is no perfect scenario, soundproofing or changing the recording environment around may be necessary.

Adding carpets, pillows, and furniture, can be a good idea to tame a wild room somd. You need a carpet for a drum kit, amd excessive foot noise can be tamed with a carpet as well. Poor acoustics ually are the result of flutter echoes, as the sound bounces around from surface to surface, slowly dissipating in the room. Pro studios have lots of absorbers and diffusion to enhance the natural acoustics of a room. While there is a hardly a perfect balance, you can modify your microphone placement, or remove things that are resonating to improve the acoustics of a room.

Speaker placement

Speaker placement and microphone placement make a huge difference as far as how the sound performs in the room. The worst places for sound are in the corner and up against the walls, because the sound immediately reflects back, or in the case of the corner, bounces around, and can create unnatural buildups in the corners. A professional control room, usually us the speakers somewhere near the middle, and with as many of the corners having some sort of absorber material or “bass traps”. Pay attention to the primary surfaces of reflection. In other words, the first immediate surface the sound hits. In the case of a speaker, the sound first hits the back wall, usually behind the listener. The ceiling is often times the worst part. While a soft absorbent ceiling is ideal, a heavy blanket or some similar fabric stapled or nailed to the ceiling is a great home studio hack.

Microphone placement

Microphone placement has a big role in what sounds are being picked up. For a regular cardioid microphone that you would use at a open mic, or concert can be used for recording. A helpful way to think is to place the microphone AWAY from what you DON’T want to hear, and towards the source. While this may seem self explanatory, sometimes, a simple angle change, or getting the microphone as close as possible to the source is the best way to avoid unwanted noise. The closer you are to the microphone the more signal will be generated, so it’s simple enough to understand how getting very close (as close as possible without touching) might be a great technique for getting a nice clean direct sound. Likewise, backing off the mic can get more a room sound, or make a thinner less direct sound that may fit better in the mix for an instrument like guitar.

Microphone Types

There are many different types of microphones. Which one is best for a given application?

There are 3 general categories of frequently used microphones in the studio. Dynamic and Condenser.

Dynamic Microphones

Dynamic mics work by moving a small coil within a magnet to generate electrical energy in the wire leading into the mixing console.

Here are some common dynamic microphones, although many others may exist.

Shure SM58
Shure Beta 52
Sennheiser MD421
Shure SM57
Beyerdynamic M201

Condenser Microphones

Condenser microphone work by charging a small metal disk to generate signal. They generally require +48V phantom power which is provided by the mic cable and mixing console.

Common Condenser microphones in the studio include:

Neumann u47
Neumann u87
AKG C414
Neumann TLM 103