In this article, we will be doing an in-depth explanation of how to use pink noise to EQ a room.
There are a few methods of how you can EQ a room using pink noise, such as doing it by ear, with the help of a reference mic, and using other gear. As all of those methods will show you issues with acoustic treatment, it’s important to address them as well. Fixing room acoustics can be done with the help of sound-absorbing materials, correctly positioning monitors, and yourself.
Let’s dig a little deeper.
Fixing room acoustics with pink noise
There are several ways how the room’s acoustic can be EQed with the help of pink noise. It can be done by ear, meaning that you would use your ears to hear any imbalance or frequencies that don’t sound right. Also, it can be done by using a reference mic with the collaboration of a laptop or iPad, XLR cable, DAW of your choice, and spectrum analyzer. Note that there’s a difference in positioning the mic depending on whether you are EQing the space for mixing or live performance. Finally, you can use digital room calibration software that will create a frequency response curve that can be applied to any audio material to eliminate inconsistencies and show specific areas of your studio that need acoustic treatment.
What is pink noise?
Pink noise was specifically designed for music-related applications and, in fact, is blank static in which every octave has an equal amount of energy, which means that you will have a flat frequency response. If you play pink noise back into your room, it will show how your room interacts with frequencies from the audible frequency range.
Do it by ear
The good point to start will be to use your ears, regardless of whether you haven’t done it before or you did many times, you ought to be aware of acoustics. With more practice, you will be able to rely more on what your ears can hear.
So, you should play the pink noise through the speakers and just use your ears. You should walk around the room and listen carefully whether you can hear the changes in the character of the sound in various parts of the room. If you put your head in the corners or in places where the wall meets the floor, you may find out that the bass frequencies of pink noise become stronger there. Regardless of the different sizes and shapes of rooms, all of them have specific resonances that allude to signals that they cancel out or amplify. And you should be able to hear these resonances as well.
Do it using a reference mic
While you’re training your ear to be as precise as possible, another good idea would be to use a reference microphone and pink noise. So in order to do it, you need a small-diaphragm omnidirectional condenser mic, XLR cable, a DAW of your choice, and a spectrum analyzer. The spectrum analyzer is needed for showing the graph with the pink noise profile and a graph that you will have after you record a pink noise in your room. That’s how you will know which exact frequency issues your room has.
After you have what you need, you have to choose for what purpose exactly you are EQing your room, as it can be either critical listening for mixing and production or live performance. In case of mixing and production, you should place the microphone where your head is going to be in the listening position. And for live performance, it’s better to take measurements at various places throughout the space.
Using digital room calibration software will help you to determine and correct frequency response issues in your studio. Using this software, you can get accurate measurements of the frequency response of the mixing position in your studio and, as a result, get a calibration profile that illustrates flaws that you have in your recording space. This software uses a reference mic with a neutral frequency response for measuring test signals played by studio monitors. The process is repeated several times at various positions in order to create a frequency response curve. Then you can apply this curve to any audio that is played through the audio system so that any issues with added coloration and frequency performance of the speakers can be fixed.
Also, digital room calibration can show you which exactly acoustic treatment specific areas of your studio need.
Importance of acoustic treatment
Acoustics is the key to every successful sonic enterprise and any space you use for recording or playing should be aimed at giving you the best result possible. The interesting part is that the human mind adjusts for acoustics, so if you’re composing in a poorly treated room or room with bad acoustics, you compensate for the lack of accurate sonic representation. If that’s the case and you’re used to hearing music the way you created it, you may not realize that other people, when they will hear it using other devices, will notice the tiny inconveniences or rather major problems that you haven’t noticed. So to never find yourself in such a situation, you have to make sure that the working space has the best acoustics possible.
Basic principles of room acoustics
Your studio is capable of creating more reflecting sound as sound waves reflect from the walls and all of the equipment in the room. So to fix the room acoustics correctly, you should have an understanding of the basic principles of room acoustics, such as sound reflection, echo, and reverberation time.
In order to achieve the best listening experience possible, you have to treat your room using either rugs or sound-absorbing materials so that when the sound wave hits the treated wall, the sound will be reflected in a diffuse manner.
The way of dealing with echoes is quite similar to sound reflections, with one small difference you need to use sound absorbent or diffuse materials on the wall from which sound waves wouldn’t bounce back.
Basically, reverberation time measures the time that is needed for sound reflections to decay until the sound is no longer audible. The rule is that the more sound absorbing material you have in the room, the lesser reverberation time would be.
Fixing room acoustics
Interestingly enough, you don’t have to invest much into fixing your room’s acoustics if we talk about your home studio. Basically, you need to use some absorbent materials and putting a sofa on the right spot, bookshelves, and curtains over a huge window will do the trick. If one surface is reflective, then the opposite one has to be absorbent.
The next thing that you want to do is to position your monitors the right way. Typically monitors have the instruction on how far from each other they should be positioned and the distance from them to the wall. Generally, 70-90 cm between monitors will do, and you should put them in a symmetrical acoustic space, on the same stands, on the rubber feet or shelf.
Lastly, you have to make sure that you have positioned yourself in the studio environment correctly. Make sure that you’re sitting from your monitors at the same distance that they’re from each other. Monitors should be at your head height with the tweeters that are pointed at your ears. So in total, it would make a triangle shape.
No one really likes when the space gives much of an echo, especially when we’re talking about the home studio, as excessive reverberation will negatively affect your recordings as it will spoil the accuracy and clarity of what you hear on your monitors. Also, it’s worth mentioning that rooms with low reverberation time might sound unnatural or dead, but rooms with high reverberation time cause bigger problems.
So to absorb unwanted sound, any amount of soft furnishing will do the trick, but acoustic panels will do it even better. These panels are capable of catching from mid to high-range frequencies. Generally, the bigger size of the panel and the number of panels in the room, the more it will absorb and the more impact it would have.
Another great option is using bass traps that will catch low-end frequencies. You will get better results if you place bass traps in the corners of the room, where low frequencies tend to have the most impact.
Also, you might want to use a diffuser as it’s capable of reducing echoes and reflections while leaving a live-sounding space. There are many shapes of diffusers, so you can choose those that would look good in your studio.
Frequency response is about how well a particular audio component is able to reproduce all of the tones that we can hear and whether it makes any changes to the signal on the way. The frequency response is split into bass, middle, and treble sections. But, frequency response isn’t just about how much of these sections are coming out of a particular sound system, but also whether there is anything that affects the tone, balance instruments of the track, or any unwanted coloration.