Ever wondered about Microphone Frequency Response? How does this work? And what should we know about this? This article will be going to discuss the things behind microphone frequency response. This article includes knowing the frequency range chart, how to read the frequency response graph, etc.
In fact, the frequency response is a significant specification in a microphone. You can get to determine the characteristic sound of the microphone through its frequency response. So, when you plan to buy a microphone, you’ll need to check its frequency response to know if it’s the right for your need. In addition, learning the ins and outs of the microphone’s frequency is helpful for your decision-making.
Let us get to know more about microphone frequency response in the following section.
What is Frequency Response?
Frequency response measures how well an audio component reproduces all audible frequencies. Also, this determines if there is any change on the signal all the way through. You will get the frequency response by adding the sum of the change in generation and the change in demand, divided by the frequency change. From there, you will get the megawatts per 0.01 Hertz or MW/0.01 Hz.
In fact, the frequency response is one significant factor when it comes to determining the sound of a microphone. In short, it is imperative to assess whether your microphone has a good frequency response in order to get good sounds. Usually, it is presented by a frequency response chart. There are two types of frequency response – the flat response and the shaped (or tailored) response.
Knowing the difference between flat and shaped response microphones
When we say Flat Response microphone, the component is sensitive to all frequency ranges equally. On a Hz frequency chart, the curves are showing almost a flat line. A flat response microphone can reproduce a sound source with little to no difference from the original sound. In short, it can possibly produce an accurate sound like the original one. A flat response microphone is perfect for recording sound effects and musical instruments. However, this kind is not suitable for recording voices.
On the other hand, the Shaped Response (or Tailored) microphone, component is quite sensitive to some frequencies than others. If you see it on the Hz frequency chart, the curves have peaked. Some microphones with a shaped response are much sensitive to low frequencies.
Thus, it reduces the pickup of handling noise and the rumble when you use it on stage while standing on the mount. Typically, it has a boost on the upper mid-range, between 3,000 to 6,000 Hz. It is also called the ’Presence Rise.’ It can enhance the clarity or punch of musical instruments as well as voices.
But, whether a microphone has a flat or shaped response, the frequency response curve should be a flat, smooth line. The lesser the peak and valleys, the pleasing sounds it can reproduce. If it has quite a lot of heights, then probably the microphone give natural sounds. In addition, it tends to create feedback with a PA system. With our technology today, some microphones allow you to adjust their frequency response. Therefore, you can adjust it to suit a variety of applications.
How To Measure The Frequency Response Of The Microphone?
There are two measuring blocks of Frequency Response – Decibels and Hertz.
Frequency is measure in Hertz (HZ) or (cycles per second), while Decibels (Db) is used to measure relative microphone output levels. But how to the microphone frequency response is measured?
When it comes to measuring the microphone’s frequency response, it is not that hard to conceptualize. But, in order for microphone manufacturers to calculate or measure frequency response accurately, they will need specific expensive equipment. These are Anechoic Chamber and a perfectly calibrated loudspeaker. What are those pieces of equipment?
The Anechoic Chamber is a space that is acoustically dead. In short, there is no ambient noise or any reflective surfaces in the room or chamber itself.
On the other hand, a perfectly calibrated loudspeaker is also needed to measure microphone frequency response. This equipment needs a flat response and must be able to reach 20 Hz to 20,000 Hz equally. Both the Anechoic Chamber and Loudspeaker require a genuinely incredible amount of design detail.
How does this work?
When measuring the mic’s frequency response, the microphone should be placed in front of the loudspeaker. Then it should be connected via XLR to a calibrated spectrum analyzer. When all these are ensured, then you can start the test.
You will play the Pink Noise through the loudspeaker so the microphone can capture the sound. The reason why Pink Noise is used for testing is that it has equal energy across all octaves. In short, the noise is equivalent in the human range of hearing.
So, if the resulting frequency range chart has peaks and valleys, then it has something to do with the microphone’s response to some frequencies. The signal of the microphone is routed to a spectrum analyzer then a frequency range chart is produced.
Is there any alternative way to measure the microphone’s frequency response?
Fortunately, Yes! There is another way to measure frequency response without using expensive equipment. Some manufacturers use this alternative in order to produce accurate frequency responses. The thing is, they are comparing against a known or high-end reference.
To measure, you just need to analyze the microphone in question against another mic having a known and accurate frequency response. Then you may need to calculate the difference and reduce the frequency response to the unknown microphone.
When you are doing this option, there are things that you need to consider first. You need to ensure that microphones are in both tests. After that, you need to take notes of this:
- Both microphones you are comparing must be in the same room.
- Everything in the room must be with both the microphones while testing and analyzing.
- The microphone must be in the same and exact position.
- Both microphones should have the same distance from the speaker.
- The microphones should have the same pink noise with the same volume.
This alternative is cheaper than using an anechoic chamber and calibrated loudspeaker. Both microphones will undergo the same stimulus. When measuring frequency response, you do not need to have a perfect loudspeaker. However, it should be calibrated in order to determine if the pink noise is flat as it can be.
Measuring the frequency response of the microphone is made possible through a frequency analyzer or spectrum analyzer. This thing presents the frequency range chart. Manufacturers need to undergo their entire microphones for testing before releasing them to the market to serve their customers better.
Basically, there are two ways to measure the microphone’s frequency response. Through the anechoic chamber and calibrated loudspeaker or the alternative, it is the comparison between known microphones having good frequency response.
Which Type Of Microphone Has The Best Frequency Response?
For the record, microphones have two main types – the Condenser and Dynamic mics. These types of microphones differ when it comes to their tonal characteristics and how they actually work.
Of course, these types of microphones have fundamental differences. The best example is their frequency response. They do not share the same frequency response as one type is less sensitive than the other. However, which is, has the best frequency response? Let’s familiarize each type first.
This type of microphone is commonly used in a live environment. Dynamic Mics is also referred to as moving-coil microphones. In reverse, this is considerably used as loudspeakers. This type is very robust and is suitable for live performances. It can withstand very high sound pressure levels or high volumes. Besides, it is very resistant to feedback, making it the best option for live situations.
When it comes to frequency response, dynamic mics are less sensitive than condenser mics, especially to higher frequencies. However, it is not a bad thing for dynamic microphones. When you need to record, or mic up loud sources without more high frequencies, using a dynamic microphone is perfect.
As the years go by, manufacturers are designing dynamic microphones for specific use. Here are some examples:
- Drum and percussion microphones
- Reed, brass, woodwind, and stringed instruments microphone
- Bullet or harmonica microphones
- Wireless microphones
For the past years, this type of microphone has been the best option for professional studios or music enthusiasts. This is because it is considerably far more common and affordable.
The diaphragm of the condenser microphone is thinner, and there is a plastic film, which is usually plated with gold. It is commonly mounted on a backplate.
The following are the main types of condenser microphones:
- Large-diaphragm condenser microphones like AKG C214 and MXL CR89
- Side-address condenser microphone – CAD U37
- Dual-diaphragm condenser – You can check this out Neumann U87 Review
- Tube condenser microphones
- Small-diaphragm condenser microphone
- USB microphone
The good thing about condenser mics is they can preserve the higher frequency content of a sound source. The sensitivity of Condenser microphones results in a higher dynamic range. Since it has improved frequency response, it is ideal for recording almost anything that requires high frequencies. It includes vocals, acoustic guitars, pianos, drum overheads, and other string instruments.
However, it is not so robust compared to a dynamic microphone, and it requires more care. Also, not all condenser microphones can handle higher sound pressure levels, unlike dynamic mics. It has higher sensitivity, making it not suitable for live performances. What is interesting is there are manufacturers designing condenser microphones for live purposes.
How to Read the Microphone Frequency Response Graph?
The frequency response graph is produced by testing the mic using an anechoic chamber. Like what we have mentioned earlier, it is a room constructed just for audio or frequency testing. It does not form nor absorb any noise and sound.
When the Pink Noise is playing, the microphone signal is routed to a spectrum analyzer. That is when you finally get the microphone frequency response graph. But, how to read the microphone frequency response graph?
Usually, the chart ranges from 20 Hz to 20 kHz. It is the range of human hearing.
Image Source: Wikimedia.org
In the frequency response chart, the horizontal numbers represent frequencies, usually over 20 Hz to 20 kHz. The sheer numbers represent the relative output level in decibels. When you look at the chart, you can tell how a microphone works at specific frequencies.
Now, you already have a heads up about microphones’ frequency response. You already know what type of microphone is best suited for your situation and need by this time. Frequency response is not that hard to comprehend, as long as you know the basics.
Knowing about frequency response is essential so you can have the best output possible. By choosing the microphone tailored to your particular need, you are likely to develop the sound you are aiming to have. It feels so satisfying getting the sound that you like without having EQ’ing afterward.
So, now you know how vital the frequency response is, you can choose the best microphone on the market for your specific need. Whether you need a dynamic microphone or a condenser microphone, it really does not matter. What matters is where you will use it!