Achieving Sound Quality Requires A Good Microphone

Whether you are recording at a studio or conducting a live interview on the scene, sound quality is best captured if you have a great microphone. Crappy audio often is the result of an inferior quality microphone or recording device. This cannot be stressed enough to creatives, who later spend on a good microphone when they realize how horrible their audio sounds on video. The audio is often neglected and this can be a price to pay.

For podcasts it becomes perhaps one of the most important piece of equipment. You cannot really do a high fidelity podcast unless you have a nice microphone. It also has to do with the mixing and sound recording system that processes the audio. For live broadcast or streaming it is even more important because the audio plays a big part of the content. You can still shoot video clips with poor audio, but for podcasting it surely makes a difference to have a low noise amplified system with a great microphone to get your message out clearly.

Microphones basically convert audible sound that can be amplified and recorded on media like tape or digital storage. It also delivers amplified audio to speaker systems directly from the source. You can use the mic without recording the audio too, like during a live talk or performance. The transducer element converts the audio from the mic into electrical energy that is then amplified with intensity and reproduced by speakers.

There are two particular types that I want to discuss.

  1. Dynamic microphones — They make a great choice when recording multiple people or in places where there is plenty of noise. It is best for the source to be very close to the mic. These mics don’t pickup background noise as much, so they are ideal for live performances, talks and podcasts. This is because they are not as sensitive to the surrounding, thus they can just pick up the audio of the person or source closest to the mic. They are durable in design and great for minimizing feedback since they are not too sensitive.
  2. Condenser microphones — They are more sensitive but precise. Condenser mics work like capacitors. Through the use of what is called phantom power, which is a +48V charge, a change in the capacitance due to the sound allows the conversion of audio to electrical energy. This power is provided either by the pre-amps or a battery source. Since the condenser mic is more sensitive, it is ideal for high fidelity sound recording with a good frequency response. It will require a quiet room though, due to the sensitivity of its components. Due to its features, condenser mics are more expensive.

All mics have an inherent noise characteristic. There is a concept called self-noise. Self-noise is the signal the microphone produces by itself, even without a sound source. It is an unwanted presence, but exists due to the law of physics. In terms of signal to noise ratio, it is expressed as the interval from 94 dB SPL (Sound Pressure Level) to the level of the self-noise, RMS, A-weighted. Luckily the job to reduce self noise is the microphone manufacturers duty.

There are two ways to measure this, also called the Equivalent Noise Level. The noise is measured in units called dB (Decibels). It is a measure of the intensity or sound level, applicable to sound including noise.

1. A-weighted RMS-measure — Relates to the ear’s sensitivity, filtering out low frequency noise. For a good result a value below 15 dB(A) indicates a very low noise level.

2. CCIR 468–4 or ITU-R 468 — For a good result, values below 25–30 dB are ideal.

Another characteristic of microphones is that a larger diaphragm will lead to lower self-noise.

Here are things to consider when selecting a microphone.

Acoustic Principle or Mic Type : Dynamic or Condenser

Polar Pattern : This indicates how sensitive a mic is to sounds arriving at different angles about its central axis. You can find out more about polar patterns at this link.

Frequency Range : The lower and upper range of frequencies the mic can support e.g. 1 Hz ~ 140 kHz. The audible range is between 20 Hz and 20 kHz.

Output Connection : The type of connector used e.g. XLR for high-end systems and USB for digital computer interfaces.

Output Impedance : Impedance is a type of resistance in a circuit. For mics, the impedance can determine at what cable length before high degradation occurs. Lower impedance is ideal for longer cable runs.

Sensitivity : This is measured by a 1 kHz sine wave at a 94 dB (SPL). The ratio of the analog output voltage or digital output value to the input pressure. High sensitivity means the mic can pick up more sounds. Example -> -57.0 dB re 1 Volt/Pascal (1.60mV @ 94 dB SPL) +/- 2 dB @ 1kHz. The lower the dB value, the more sensitive the mic is. A sensitivity rating of -44 dB is more sensitive than -55 dB.

Here are some things to add to a microphone to get better performance.

Pop Filter — This is placed between the source and the microphone. It functions to reduce popping sounds from the air and mechanical impact of fast moving air. It can also prevent saliva from getting on the mic. This is most common in recording studios and can also be used by podcasters or live streaming talks.

Windscreen — This is usually found when recording audio outdoors in windy environments. They function much the same way as pop filters.

I am not going to give any product endorsement, so I would rather not answer this question directly. A good audio engineer can make recommendations, but the truth is that it really depends. You can review products from trade magazines that provide detailed information on the latest and greatest products. Higher end brands tend to be the best but most expensive as well.

For creatives who stream on platforms like YouTube or podcasts, perhaps a good microphone is ideal. This is because it provides better sound quality for content. YouTube is not just video anymore, since vloggers like to talk and tell stories. Having a good microphone provides better audio quality.

For recording, a combination of microphones that include both dynamic and condenser type is common. For recording the specific instruments with minimal background nose, dynamic mics can be used. When recording songs a condenser mic gives better precision and frequency response, but requires a really quiet room or studio. In other words it is excellent for recording vocals.

For gamers who use platforms like Twitch, any microphone will usually do. There are various types available in stores that include headphones or mics integrated with headsets. These type of mics are cheaper and usually good enough for conversations depending on how fast the Internet connection is (audio quality over IP is dependent on low latency networks).



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Vincent Tabora

Editor HD-PRO, DevOps Trusterras (Cybersecurity, Blockchain, Software Development, Engineering, Photography, Technology)