Necessary equipment, settings and tricks to improve the sound quality in your videos or in your live shows.
The path that sound follows
Here is a very simple outline of the path that the sound takes from the original source to the person who finally hears that sound. The example is applicable to both recording and live broadcast.
We can control the first part.
What affects the sound quality?
Factors that affect sound quality and that we have to take care of:
- The ambient noise : any unwanted sound collecting microphone, including for example the reverberation if we are inside
- The quality of the microphone and its correct use (almost always the fact of using it correctly has more influence)
- The cable that connects the microphone to the preamp stage
- The quality of the preamp . The signal coming from the microphone is very weak and needs to be amplified. At this stage, the electronic noise and distortion introduced by the preamp has a lot of effect on the final result.
- The quality of the analog to digital converter (ADC)
- The recording levels : get the appropriate level to optimize the signal to noise ratio while avoiding saturation (clipping)
The color of sound
What is this sound color …?
In the world of sound, color is used as an analogy because the language related to vision is richer than that related to hearing.
When a sound is emitted, that sound has a certain frequency distribution. A bell. The timbre is like the signature of a sound, which allows us to distinguish the voice of different people or the sound of different instruments.
Sound is transmitted through a medium (the path of sound, including electrical, digital, etc.) and reaches the person who listens to it.
If the sound arrives with the same timbre, the same frequency distribution, then we would say that the transmission channel is transparent.
In the real world, all phases or stages from when sound is emitted until it is received introduce some kind of change in the frequency distribution.
The mark that each element of the chain leaves on the sound (in its timbre, not in its amplitude) is what is known as color
The microphone
The microphone is usually the element that usually affects the most, the one that contributes the most color to the original sound.
A microphone is considered good if it is very transparent (true to the original sound) or if it adds a pleasant color to the sound it picks up.
A bad microphone is one that does not pick up sound well, distorts it, or adds an unpleasant color to most of the sounds it picks up.
Just because a microphone is good does not mean that it is good for all sounds and all situations.
For each instrument, type of voice or musical style there is a microphone model or a combination of them that best fits and gives it that special color.
Starting from a certain level of build quality and technical characteristics, all the microphones are very good. The difference between models and ranges would be in those nuances of color and in the specialization.
Some of the positive and negative characteristics of a microphone can be reinforced or corrected by editing the sound, using filters, equalization, etc.
But there are more subtle features that have to do with the physical construction of each mic and are very difficult to correct or emulate in post production.
Preamplifier
The preamp (the entire analog signal manipulation chain) is another element that can add color.
Each amplifier has its own frequency response. Also, if the amplifier is not completely linear it will introduce harmonics, frequencies that were not part of the original sound.
As with microphones, that preamp footprint can be good (if it generates ear-pleasing ‘distortion’ or EQ) or it can be bad, if it introduces distortion or EQ that is annoying or does not match the type of sound being picked up.
Once the sound signal is digitalized, it can be manipulated in many ways: equalization, compression, filtering … but there we would already have control, it is basically manipulating numbers.
Types of microphones. Summary
According to the principle of operation:
- Dynamic
The membrane is attached to a coil that moves around a magnet. The movement generates an electrical signal by induction.
They do not need external power.
They isolate ambient sound very well (since they have little sensitivity)
They are very resistant to shocks
Good behavior for the voice - Condenser
The membrane moves one of the plates of a condenser (in the microphone capsule) and causes voltage variations: it converts changes in sound pressure into an electrical signal.
They need external power.
Very high sensitivity, they capture weak sounds better
Better frequency response, more transparent (depends on the physical construction)
They are very delicate: blows or very loud sounds can break them
Good behavior for voice and almost all kinds of instruments
According to the way they pick up the sound around them (sound pickup patterns)
- Omnidirectional
They collect sound equally in the entire sphere around them. They are ideal for example to pick up ambient sound - Cardioids
are more sensitive in one direction, a hemisphere really. That is, if they are pointing in one direction, all the sound that comes from behind or from the sides will be very attenuated. - Supercardioid, hypercardioid …
Different versions of directional microphones, with narrower pickup angles. They are typical patterns of shotgun microphones. - Bidirectional
Basically they would be like two cardioids united in a single microphone. They pick up sound from the front and rear, and attenuate sounds from the side.
How to get studio quality sound?
With relatively little we can achieve ‘professional’ quality sound.
Once that level is reached, the improvements would already be small, we would need to invest in professional range equipment and it would not be worth it if we are going to use a video broadcast or publication platform, since they will apply their own compression systems.
What are we going to work on?
- In the ambient noise
- In the acoustics of the room
- Choosing the most suitable microphone
- Use the microphone correctly to get the most out of it
- Try to use a good preamp
- Correctly set audio levels
Reduce ambient noise
External noise from the street, neighbors, family … there are things that we cannot control.
Soundproofing a room is very complicated and expensive. This is not normally an option.
Yes we can control some sources of noise in the room itself: air conditioning, fans …
A dynamic microphone can be a good solution because they tend to have low sensitivity. It forces us to speak near the microphone but it rejects the sound that comes from outside very well and for voice the response is very good.
We can also play with the pick-up pattern (polar diagram) by placing the microphone so that the active direction, the most sensitive, points towards the area most protected from noise.
In any case, it is interesting to speak very close to the microphone, so that it works with the least possible sensitivity.
The acoustics of the studio
Sound waves reflect off the rigid surfaces of any enclosed space.
The main sound reaches the microphone first, but then the versions that have been bouncing off the walls, floor and ceiling will arrive. With a lower intensity, but out of phase in time.
If the room is very large, the lag is perceived by the brain as an echo. When the lags are small (small enclosures) the effect is known as reverb
When the reverb is very large, there are unwanted effects.
Interference patterns cause some frequencies to be boosted and others to be canceled (an effect known as a comb filter)
Audio picked up by the microphone will sound distorted and unpleasant.
Reverb at lower levels is not unpleasant, quite the contrary. A sound with reverberation sounds natural to us because we are used to hearing in closed environments.
Improve acoustics
What to avoid above all are direct rebounds .
Direct bounces are generated from bare surfaces: walls, floor and ceiling, which act as mirrors for sound waves.
You simply have to place elements on those surfaces: pictures on the walls, curtains on the windows, rugs on the floor …
These elements absorb on the one hand part of the energy of the waves, weaken them (especially fabrics and soft materials) and on the other hand introduce additional rebound angles.
The bounced waves now reach the microphone with a lower amplitude and the phase shift is no longer localized as it was with the primary bounces.
No need to go crazy, a normal room decoration should already generate an acceptable level of reverb
Depending on the configuration of the space, if we have the wall directly in front close, we may want to protect it a little more to avoid the main bounce.
The lower frequencies, the bass , can create some additional bumps.
These types of waves only ‘see’ large surfaces and are easier to generate direct bounces.
If the geometry of the room acts as a resonance box for certain frequencies, additive or destructive interference can be created: sometimes it gives the impression that the bass loses strength, other times the opposite effect, the bass is amplified or an annoying reverb is generated .
If any of this occurs (and it is not due to resonances from the microphone itself or its support) it may be necessary to reconfigure the space a bit to see if it is corrected or the option of placing bass traps in the corners should be seen.
Choosing the most suitable microphone
In studio we have quite a bit of control over external parameters and can focus more on sound quality.
My criteria would be to prioritize quality whenever possible , but we will see situations where we will have no choice but to sacrifice a little quality for more flexibility, or simply for convenience.
There is no universal solution.
The most important thing is to know why we do things : pros and cons of each option, the technical limits and how to get the most out of the team we have at that moment.
We are going to make a list of options (type of microphone) prioritizing the sound quality that we could achieve with this solution and we are going to go down through different options that would be a compromise between quality and flexibility.
- XLR studio microphone + audio interface / mixing console
It is the option that would theoretically give us more sound quality. We have control over the microphone, over the preamp and all the analog electronics (sound interface). We minimize the effect of background noise. - USB studio microphone This
is the simple version of the previous option. A USB microphone includes everything: the microphone itself and the sound interface: the preamplifier, the digital converter … We lose a bit of flexibility (and a bit of quality) but we gain in ease of use and comfort. - Lavalier / lavalier microphone (cable)
Very good option because we keep the microphone close to the sound source. The final quality will depend on the microphone itself and the preamplifier that we use. We will see different configurations below. - Lavalier microphone (wireless)
It would be a very good solution if we record or broadcast live doing some physical activity or if we move around the scene. We keep the microphone very close to our mouth and we take the hassle out of the cable. - Directional shotgun microphone
It allows us to place the microphone a little further away from the sound source. It is an option when we want to completely remove the microphone from the frame and it is a very comfortable solution: it allows us freedom of movement and the initial setup is very simple. - Headphones / headphones with microphone These
would be the typical gaming headphones. It is very difficult to find models that include a decent microphone. But sometimes it can be the most practical option. - Bluetooth headphones with microphone
It would also be an option that we would choose for reasons of ease of use but in general we would subtract sound quality compared to other solutions.
We are going to see each type of microphone that we have discussed, with its pros and cons, and the most common configurations.
XLR studio microphone + sound interface
In principle, it is the solution that can give us the best sound quality and at the same time it is a very flexible option.
In sound there are two great worlds: equipment for professional use and consumer electronics equipment.
Each one has its quality standards, its rules and its way of working.
The XLR microphones, the sound interface or the mixing console would be part of that world of professional electronics.
Be careful, it does not mean that a computer is excellent because it is XLR (XLR is only one type of connector / cable). There will be everything, including lousy equipment.
But the idea is that if we choose a decent mid-range team we will be working with quality standards very close to those of a professional production. And you do not have to spend a fortune, we have at our disposal equipment with an excellent value for money.
Another advantage of this configuration is that the XLR cables are balanced cables . These types of cables protect the signal coming from the microphone (a very very small signal) very well from external interference.
How to choose XLR microphone?
XLR is not really a type of microphone. It is a way of differentiating, so to speak, that the microphone works with the standards of the professional range.
There are literally thousands of known studio microphone models (aside from unknown brands, cheap copies, etc.). We already said at the beginning that each situation, type of voice, type of instrument … has that microphone model that suits the best and provides a color that favors the sound.
But for normal use you don’t have to go to that extreme.
The rule that is usually applied is that of 100 euros (or dollars, as you prefer).
That guide price would be the cut that usually separates the microphones that are already going to offer a more than acceptable quality.
Above we would have higher quality microphones, but the differences in the sound would already be subtle and it is more a matter of the specific color they contribute to the sound.
Below that cut we can find everything, but let’s say that it is more likely to find models with design problems (resonances of the frame) and construction (materials and elements of the membrane / capsule).
It’s not a very scientific criterion, but it usually works.
Criteria for choosing :
- If you are going to work in an environment with some ambient noise, perhaps a dynamic microphone is a better option.
- If you are going to work in a controlled environment: a condenser microphone
- Large diaphragm condenser microphones tend to be great for vocals
- Small diaphragm condenser microphones are usually very transparent (very flat frequency response) and are great for almost every use. Then in the editing part it can be equalized to reinforce the midrange or bass a little more depending on the type of voice or the instrument.
- Choose a known model from a known brand
- In microphones, price is usually related to quality . But from a certain threshold we would have a very good base quality and the increases would already be subtle as we go up the range.
Sound interface
To use the XLR microphone you will need a sound interface (and an XLR cable)
The sound interface takes care of:
- Provide power to the microphone if you need it (condenser microphones need external power, which is known as phantom power)
- Amplify the microphone signal (preamplifier)
- Convert analog signal to digital signal
- USB communication interface with computer
- They normally include other inputs: for instrument (eg guitar) and line (eg for keyboards)
Criteria for choosing a sound interface:
- Pick a familiar model from a well-known brand . As with microphones, there is a minimum quality threshold. It is noticeable above all in the quality of the preamp and the analog-digital converter.
- If you are only going to record voice with a microphone you can choose an interface with a single input, but in general I recommend choosing a model with at least 2 microphone inputs (the inputs are usually hybrid, you can connect, for example, a microphone on a channel and one instrument in another)
Sound interface or USB mixer?
A traditional mixing console is a device that works with the analog signal: analog inputs and analog output.
There are mixers that include the digital part: analog-digital converter and the USB connection interface.
A mixer of this type would give us a little more control over the analog part and it would make our work a little easier if we are going to use several audio sources at the same time: several microphones, microphones and instruments …
Nowadays all that part of mixing and channel management can be done in the digital part, from the computer.
The choice of an audio interface or a mixing console (USB) is therefore a matter of personal preference.
Tips / correct use of studio microphones
- All microphones, except omni-directional, have an ‘active’ part, which is what we have to talk to. In some models it is the upper part, in others it is one of the sides, etc. depending on the location of the membrane. If we speak to the wrong part of the microphone the sound will lose a lot of quality.
- The microphone has to be close to the mouth and in the direction of the sound we emit. The optimal distance between the microphone and the mouth would be between 15 and 20 cm, but it depends a lot on the type of voice and the effect you want to achieve. The shorter the distance, the more the bass is usually reinforced and if we are very close, the proximity effect is produced (distortion that greatly increases the bass).
- Use an anti-pop filter
- Somehow isolates the microphone from the table (shock mount / separate mic stand) so that vibrations and shocks are not mechanically transmitted to the microphone
- Play with the microphone’s directional pattern to isolate external noise sources (eg a window facing the street)
- Only your voice (or an instrument, etc.) should sound in the room. The computer speakers must be turned off. You would have to wear headphones to monitor the sound.
- It is very important to correctly adjust the gain of the preamplifier to optimize the signal-to-noise ratio but keeping a sufficient margin to avoid saturation (clipping)
USB studio microphone
USB microphones are a kind of all-in-one: microphone (usually condenser) + sound interface.
It is a very comfortable and easy-to-use solution , you just have to connect the microphone to the computer with a USB cable and that’s it.
With respect to a configuration with an XLR microphone, we lose flexibility and a bit of quality.
To visualize it in a simple way, think that a 100 euro USB microphone will have inside it a 50 euro microphone and a 50 euro interface.
And we lose flexibility because the whole pack goes together. Imagine that a dynamic microphone is more convenient in your studio.
USB microphones would be in the world of consumer electronics.
To record sound for videos (to publish on YouTube or similar) or for live, I think they generally offer an acceptable quality.
To record a song, sing, etc. I would choose the XLR microphone + sound interface option.
The tips for use would be the same as for a studio microphone .
Lavalier / lavalier microphone
This would be a solution if you don’t want the studio microphone to be seen (remember that the ideal is to place it a few inches from the mouth)
Here are some popular midrange lavalier mics (with 3.5 jack plug)
All these microphones would be in the consumer electronics part.
And everything that goes through unbalanced cable and jack connectors usually generates a certain level of hiss noise (a kind of shsssssss that sounds in the background, especially in the silences)
There are also slightly higher end lavalier microphones with XLR connectors.
Keep in mind that the sound quality sent by the microphone can be affected depending on the next stage (preamplifier).
We are going to see different configurations:
Direct microphone to computer
The microphone connector would go to the microphone input of the computer (see below the whole topic of the TRS and TRRS connectors to avoid problems).
The problem with this option is that the preamps that carry the integrated sound cards of the computers are usually quite bad.
You will have to prove in your case.
Sometimes the problem is with the computer, other times with the specific combination of microphone and computer.
If you see that the electronic noise level is very high and degrades the sound quality, you can try a simple sound interface:
Direct-to-camera microphone
If you are recording it is possibly the most comfortable option because the video and audio will already be synchronized in the video file.
If you are going to broadcast live, you will have to see if your camera sends the audio signal together with the video signal: through HDMI if you use a video recorder or through USB if you use this method.
The preamps built into cameras are usually not very good, but they are surely better than those built into computers.
Microphone to external recorder
To record is one of the best options.
Recorder preamps are much better and in general a digital recorder offers much more control over the sound.
If you are going to do live, you will have to see if your recorder can function as a sound interface. Some models allow you to connect the recorder to your computer via USB and you would normally have a cleaner sound.
Microphone to audio interface / mixing console
It would probably be the best option in terms of sound quality, but it means investing in a sound interface or a USB mixing console.
These teams are part of the ‘professional’ world: XLR connectors and 1/4-inch jack
You will have to see if the model includes any input for 3.5 jack
If not, you could buy for example a 3.5 jack to XLR adapter
Lavalier microphone + wireless system
This would be an ideal combo for those types of live shows in which the person is doing some physical activity (fitness, yoga…) or is away from the camera and needs to move freely around the scene.
The microphone is independent of the wireless system.
Think of the wireless system as simply a transmission channel: a transmitter with a microphone input and a receiver with an audio output .
Everything that we have discussed about the connection options would apply equally to the receiver : it can be connected directly to the camera’s audio input, to an external recorder, directly to the computer or through an audio interface / mixing console.
Advantages of the wireless system:
- The microphone is always close to the person’s mouth, regardless of how they move and where they look.
- We eliminate the cables. There is only a small cable that goes from the microphone to the bodypack (transmitter). The receiver will be placed next to the camera or next to the computer.
Disadvantages:
- The price. To achieve a minimum of quality you have to go at least to mid-range systems, where we can find a good value for money. For professional range systems the prices would already be in another order of magnitude.
- More elements are involved and therefore the probability that something will fail increases: the transmitter battery, the receiver battery, electromagnetic interference … But hey, once you have experience you already know what to check and how to solve it quickly.
How about bluetooth systems?
It is not usually a good option if we are looking for quality.
The transmission capacity is limited, they can only use a pre-compressed audio signal. All the preamp, digital conversion and compression part would be done by the microphone itself, we have no control over that part.
The quality of the microphone itself. They are devices designed to carry on a telephone conversation, not to transmit high quality sound.
Directional / shotgun microphone
These types of microphones are designed to work at a slightly greater distance from the sound source.
There are professional range shotgun microphones with XLR connection, but here we are going to refer above all to the ‘on camera’ shotgun microphones that are designed to work with consumer range equipment: external cameras and recorders for example.
We can simply place them on the camera’s hot shoe or a better idea is to place them on a small tripod, on an articulated arm or on a tripod or mic stand, in such a way that they are positioned pointing to the face, relatively close (but outside of the frame if we want it).
This option is also interesting if we are going to be moving around the scene or doing some activity. Because in those cases using a cable can be somewhat cumbersome.
The directional microphone gives us freedom, but we have to get used to always speaking towards the microphone, and we have to try to maintain a more or less fixed distance between the person speaking and the microphone, to avoid that the sound level varies a lot.
In this type of configuration, the acoustics of the room are very important because the microphone will more easily pick up all the sounds that bounce off the environment. Try to avoid bare walls, floors with a very large free surface, etc.
Also keep in mind that shotgun microphones usually use an interference tube to increase directionality. Interference tubes are more sensitive and more dependent on room acoustics . The principle of operation is altered by reverberation and frequency-selective comb filtering effects can be produced.
The connection possibilities would be the same that we have discussed with the lavaliers: to the camera, directly to the computer, through a sound interface …
Headphones / headphones with built-in microphone?
In general, it is not usually the option that will give us the best sound quality.
For some strange reason, the manufacturers of this type of device (especially those oriented to the gaming sector) focus all their effort on the part of the headphones and then add a microphone garbage.
This happens even with high-end headphones and / or headphones.
If for a practical matter you prefer to use this type of headset with a built-in microphone, try to find a model that includes a microphone with at least an acceptable quality.
Headphones required?
All the sound that is emitted in the studio will be captured by the microphone.
If the computer, for example, is reproducing the streaming sound through its speakers, feedback may occur (the microphone is attached) or unwanted echoes may occur.
The same applies to recording.
As a general rule, your computer’s speakers should be turned off .
Live broadcast can be done without headphones.
You always have to monitor the audio by means of a visual indicator (a digital audio meter) and you should be aware that the levels are correct: that we are emitting with a sufficient level and that we do not reach levels close to saturation (clipping)
However, it is also convenient to have an idea of the sound quality, that there are no strange noises, etc. and in many cases we need to listen to the alert sounds of the transmission.
If you are mixing your voice with music from the computer, or the sound of a game, etc. direct monitoring with headphones is recommended.
Optimal audio levels
Why is it important to manage the audio levels correctly?
The quick answer is that we want to offer the user the best possible experience , our user is the person who will listen to our podcast, our video or our live.
The objective will be:
- Achieve a suitable level
That is, a signal level somewhat enough so that the user can listen correctly without having to increase the volume of their equipment excessively - Avoiding clipping distortion
In the digital audio environment, clipping is enemy number 1. Clipping occurs when peaks in the audio signal try to exceed 0dB on the digital scale. Nothing can top that digital ceiling, therefore the signal is clipped and a very nasty distortion occurs. - Meet the requirements of the broadcast or publishing
platform Most platforms include requirements or limits for audio levels (referenced to sound perception using the LUFS standard). If we go beyond these limits, the platform automatically limits our audio and in general we will lose sound quality. - Be consistent
A good user experience is achieved when all our videos, podcast episodes, live shows, etc. maintain consistency and are consistent when it comes to audio levels. It is very annoying from the point of view of the user having to constantly adjust the volume of their equipment every time content is opened.
The advantage of the digital world is that the audio signal is referenced to a fixed universal scale (dBFS). All users who receive our audio will receive the exact same version. We cannot control in which equipment each person will listen to it, their preferences in terms of volume, hearing capacity, environment, etc. but we can control that our audio has the appropriate levels.
TRS / TRRS jack connectors
The subject of connectors seems like a nightmare at first, but it really is silly.
In the consumer range, 3.5mm jack connectors are used (the ones we see every day for mobiles, cameras, etc.)
There are 3 types, but one of them we will never use (TS), so we only talk about the two most frequent:
- TRS . Has 3 metal connections (2 black separating stripes)
- TRRS . Has 4 metal connections (3 black stripes)
TRRS connectors are used mainly in mobiles, because 3 independent channels are needed : left and right channel for headphones and an additional channel for the microphone. One of the connections is the neutral, common to all the channels.
TRS connectors are used in audio equipment (for headphones and earphones for example). They can only carry the signal of two channels: eg left and right channel of the headphones.
The microphones typically use connectors TRS .
There are microphones specifically designed for use with mobiles that already come with a TRRS connector.
The cameras having external microphone input connector often used TRS .
The computers typically use two connectors TRS : one for the output of earphone and one for the entry of external microphone.
There are computers that also use TRRS, such as mobiles.
If you use the wrong connector, that is, if you mix TRS with TRRS or vice versa, it may happen that it works, that it works half (it is heard low and / or with noise) or that it does not work or the device detects it.
It is best to always use the correct connector. And for this you can use adapters. Sometimes you will need a TRS to TRRS adapter.
Other times you will need a TRRS to TRS adapter.
Accessories Needed for Microphones
Shockmount / isolate microphone from table
If the microphone is directly on the table, any vibration or shock on the table will be transmitted to the microphone in the form of a mechanical wave and the microphone will pick it up as sound (usually annoying).
Ideally, use some type of anti-vibration system (shockmount) that isolates or attenuates these vibrations.
Another option is to place the microphone on a boom whose base is off the table.
Anti-pop filter
When we speak, we generate some sounds by emitting a jet of air (consonants like p or b ).
If the microphone membrane is very close and in the direction of the air jet, the microphone will pick up both the sound and the additional pressure from the jet. And that pressure translates into a ‘ pop ‘ sound that is very annoying.
To avoid this effect, anti-pop filters can be used: a membrane that lets sound through but acts as a diffuser for the air stream.
Another option is to position the microphone membrane at an angle to the direction of your mouth. In this way the sound is collected well but the air jet does not impact directly.