How to Use Pink Noise to Tune/EQ a Room

Mixing Board

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At the risk of sounding trite, the point of music is to make sound that makes people happy. I don’t think a more basic definition of music is possible- beyond that, all bets are off. But regardless of the way you are making music, and how you are trying to sound good, we can agree on one thing. Music is about creating and controlling sound.



The Importance of Acoustics

The often-forgotten element in this process is acoustics. Whether we are discussing a practice space, live venue, recording room, or critical listening room for mixing and producing, acoustics make a huge difference. What’s the point of trying to express yourself sonically, if your message is going to be sabotaged by bad acoustics? A musician should always be aware of the acoustics of their space.

The tricky part is that the human mind adjusts for acoustics, just as it does for light. So if you are producing music in a room with bad acoustics, you might not even realize that you are subconsciously compensating for poor acoustics. But you may create music that only sounds good in your room without realizing it. Other people will play the music in cars, phones, computers, good speakers, etc, and your mix could have major problems that you overlooked. If you are putting on a live show, you might not be paying attention to the acoustics of your room. But audience members who have heard better acoustics will walk away unimpressed.

Fixing Room Acoustics

Band Playing at Bar

Of course, depending on what you are trying to do, there are different processes involved to fine-tune the acoustics of your room. But no matter what you are trying to accomplish, there are some basic principles that always apply. Room sound problems tend to fall into two categories: frequency problems and reverb problems.

Reverb Issues

For most acoustic treatment, we want to minimize the natural reverberation of a space, so that the music’s own reverb can be heard and the sound doesn’t become muddied. (The main exception to this is concert halls and churches for classical and acoustic performances- these are usually intentionally reverberant to amplify the performers.)

Frequency Response Issues

On the other hand, a room with frequency problems will unnatural amplify or mute certain frequencies in music. Ideally, any performance, rehearsal, recording, or listening space will have as “flat” a response as possible. That way, the music can speak for itself, and be heard the way it was meant to be heard.

If your room is not treated, and the frequency response is uneven, you have a few paths to take. You can tune the room itself with audio treatment- usually blocks and panels of foam. And you can tune your speakers or PA by adjusting their EQ. There’s no substitute for fixing a room with physical audio treatment. But it can be expensive and involves installing physical treatment in the room- not always an option. Tuning a room with EQ is more of a band-aid. It can make an improvement, but it can’t fix all problems.

But to tune any room, you have to know what problems you’re trying to fix in the first place. Pink noise and programs like SMAART can be an excellent starting point here.

Pink Noise

You have probably heard of white noise, but you might not know that it actually has a scientific definition. White noise sounds like random distorted static, but it’s actually a sound that has equal power at every frequency across the audible spectrum (approximately 20Hz – 20,000 Hz). Pink noise is a variation of white noise that specifically designed for music-related applications.

Pink noise sounds similar to white noise- blank static. But pink noise has a different technical definition. In pink noise, each octave has an equal amount of energy. In other words, the power spectral energy is inversely proportional to the frequency. This is not necessary to understand in order to use it. All you need to know is that when you are tuning a room, use pink noise.

Using Pink Noise To Tune a Room

By Ear

You can start by using your ears. After all, at the end of the day, music is subjective, and our perceptions of it matter. The longer you are aware of acoustics, the more trained your ear will become, and the more you can rely on your ear in lieu of fancy technical processing. Try a website or app such as Quiztones to train your ears’ precision.

Try playing pink noise on your speaker or PA system, and use your ears. Walk around, and observe any changes you detect in the character of the sound at different points of the room. For example, bass frequencies build up and amplify in corners. You should notice the bass frequencies of the pink noise become stronger if you put your head where the wall meets the floor, or where two walls meet. Rooms also have certain “resonances” which refers to signals that either amplify or cancel themselves out due to the size and shape of the room. You may be able to hear these by ear as well.

While you are at it, try playing pink noise through just one channel, and then the other (for example, Left and then Right.) You might notice differences between the two!

Using a Reference Microphone

Honestly, you should not rely on just your ear until it is very precise, and you are very experienced- in which case, you’re probably not reading this page anyway. You can use a laptop and a reference microphone, in conjunction with pink noise. This way, you can make scientific observations that will almost certainly go beyond what your ear is telling you.

Several software options are available for tuning a room. SMAART is the (expensive) industry standard, capable of tuning huge venues for touring acts, dive bars, places of worship, and everything in between. Many pros take courses specifically to train to use SMAART. On the other hand, Room Equalization Wizard is a bit obtuse, but free and powerful. I am a full-time freelance producer and songwriter, and I personally have had great experience using REW to tune my recording and listening rooms. If your goal is to measure a room’s frequency response using pink noise, you can even use a DAW and spectrum analyzer of choice, and do things independently.

DAWs

A DAW (Digital Audio Workstation) is a host program that can record and process audio- it takes the place of tape machines, and VSTs take the place of effects units. Audacity is not beautiful, but it’s a free open-source DAW. Reaper (my personal favorite) is extremely powerful, has a free trial, and a bizarrely inexpensive one-time price of $60 to own. (Pro Tools, the industry standard, costs $599 by comparison.) The Apple-only Logic Pro is becoming an industry standard as well. FL Studio, Ableton, and Reason are also popular choices.

Spectrum Analyzer

Pink Noise Frequency ProfileA spectrum analyzer is an audio processor that shows a graph representing a sound’s frequency profile. The graph shows pink noise’s profile. Recording pink noise in a room and comparing its frequency profile to the picture can reveal room frequency issues. This blog post links to a handful of free spectrum analyzer VSTs- take your pick!

Gear

To use pink noise to tune a room, you will need some specialized gear aside from your laptop. First of all, specialized microphones exist specifically for measuring rooms. These “reference mics” are usually small-diaphragm omni-directional condenser mics. The comparably-priced Behringer ECM8000 and Dayton Audio EMM-6 are equally good choices. I usually encourage people to buy better-than-bottom-shelf mics for recording, but for tuning a room, these are just fine. dbx also offers the slightly more expensive RTA-M. I personally trust dbx to be better manufactured and last longer, but as I said, any of these will do the job.

If you don’t have one, you will need an audio interface too. The Focusrite Scarlett Solo is an eternally popular choice for all kinds of new musicians and producers, and it’s a great choice at that. If you only need an interface for the purpose of room tuning, and don’t anticipate needing it in the future, try the very inexpensive Behringer U-Phoria. It may have reliability and quality control issues, but as I said, if you need it just for this, it might be worth the savings. Finally, you will need an XLR cable to connect the mic to the interface.

If you are tuning a room for critical listening (such as mixing or production) place the microphone where your head will be when in the listening position. If you are tuning a room for live performance, try taking measurements at different places throughout the audience’s space. Which software you are using to analyze your results, and whether you intend to use EQ and/or physical treatment to fix your room, will determine what to do with your measurements. You are best off finding a specific guide that fits your needs beyond this.

Conclusion

Creating perfect acoustics in a space is impossible. Improving a room’s acoustics is very possible, and the average person can learn to do it. But it’s also a specialized skill that can take years to truly master. Still, I hope this guide is a useful starting point to use pink noise to inform room corrections. You will be shocked by the difference in how music sounds in your space once you have started to tame its acoustics. Keep on working, and feel the joy of the music!