“No need to buy absorbent panels for your studio’s acoustic treatment, just put up cardboard egg boxes…!”
Have you heard that before?
I’m not surprised, it’s one of the most widespread myths regarding acoustic treatment.
The fact is that it’s a complex subject, and if you want to have a studio with good acoustics, you need to be patient and take the time to understand what you’re doing.
That’s why I wrote my Acoustic Treatment Guide — to provide you with all the necessary information in a centralized manner.
That said, beyond that, it’s also useful to know about bad practices. That is, the “hearsay” that doesn’t contribute much to the acoustics of (home) studios, and may even imbalance it instead of improving it.
Hence this article — to put an end once and for all to the misconceptions on the subject! 🙂
1. You absolutely need perfect treatment to make a good mix
It’s often read on forums that without acoustic treatment or if it isn’t perfect, it will be impossible to make a good mix.
Fortunately, this statement is false, and for several reasons.
First of all, there is always the possibility to use headphones for mixing. Certainly, it’s not always ideal — but it’s a good way to check the behavior of certain frequency bands without being dependent on the room’s acoustics.
Moreover, even if you exclusively use monitoring speakers, it will always be possible:
- to mix at a lower volume to minimize the perceived effect of certain reflections
- to take the time to understand the limitations and problems of the equipment used and the room where you mix.
A perfect acoustic treatment does not exist.
On this last point, for example, you could choose to check your mixes on other listening systems (phone, car…) or compare them with a known high-quality commercial mix. We’re talking about using “reference tracks,” and this will help you highlight the acoustic flaws of your room.
Finally, in any case, a perfect acoustic treatment does not exist. A room will never be completely flat in terms of acoustics.
Certainly, it’s better to mix in a room with partial acoustic treatment than nothing at all. But even if it’s not perfect, it is entirely possible to achieve excellent mixing quality!
2. There should be no sound reflections in the room
One of the most common misconceptions is that to record or mix in “studio” conditions, to achieve that coveted professional sound, the room must be completely “dead.” That is, there should be absorbent panels on all walls so that there are no acoustic reflections in the room.
However, if the room is dead in terms of acoustics, the sound will not be natural at all. It would become an anechoic chamber, in a way.
On the contrary, it is usually preferable to have acoustic treatment that does not cover all the walls (and includes diffusers), in order to control reflections and modal resonances without completely eliminating them.
Don’t believe me?
Just look at the famous Studio 2 at Abbey Road, where the Beatles, Adele, and Pink Floyd recorded…
In this photo, you can see that the room is not covered with absorbent panels, quite the opposite!
Sure, some portable panels are sometimes positioned to facilitate recording, but the room is far from being “dead”… On the contrary, it greatly contributes to the ambiance and quality of the sound recordings.
3. Acoustic treatment is mainly for recording
Often, we tend to think that acoustic treatment is mainly for sound recording, that is to say, for the recording phases also known as tracking.
It’s true, after all: it’s at this moment that the room’s resonances are most noticeable, as the microphones capture the natural reverb of the space. If it is too present, it shows up in the recording.
That said, the influence of reflections off the walls of the room is just as important for mixing and mastering.
Indeed, since the reflected signals are not in phase with the emitted ones, sound waves tend to cancel each other out or amplify. Some frequencies will stand out, while others will disappear.
In other words, the perception of frequencies is altered, which will of course influence all the decisions made during mixing — particularly regarding the adjustment of reverb.
Ultimately, the lack of acoustic treatment is almost worse for mixing than for recording: for example, during recording, you can always bring the microphone closer to minimize the effect of reflections on the sound capture. For mixing, however, having appropriate acoustic treatment is the only solution.
Moral of the story: if you use monitoring speakers, acoustic treatment is essential to truly benefit from their qualities! 🙂
4. Egg cartons, carpets, mattresses…
Let me return to my introductory example from this article.
Acoustic treatment can be quite expensive, and it is clearly not the most fun part of building a studio or home studio. So, naturally, a number of “cheap” ideas have emerged over the years…
… such as putting egg cartons on the walls instead of foam or mineral wool absorbent panels.
However, it doesn’t work.
As for mattresses and other carpets, while they can be useful in some cases, they cannot fully replace proper acoustic treatment.
Indeed, properly treating the acoustics of a room or studio does not simply involve covering the walls with somewhat absorbent materials.
First of all, the amount of material is extremely important: between 10 cm of mineral wool and a few millimeters of egg carton, the difference is huge in terms of absorption capacity.
Moreover, not all materials are equally effective, as their ability to absorb a frequency depends, beyond thickness, on two physical properties:
- their density;
- their resistivity to the passage of air.
So, where does this myth come from that egg cartons can replace mineral wool or acoustic foams for studios?
In fact, egg cartons (and carpets, for example) do absorb a little. But only in the high frequencies, to which we are quite sensitive. This is shown in the graph below, where a high absorption coefficient indicates a better ability to absorb a sound wave:
The result: it seems better, but ultimately the room is still not balanced since only the high frequencies are absorbed.
In comparison, a 5-centimeter thick mineral wool panel will be much more effective as it will absorb much better and over a wide range of frequencies.
5. Just use acoustic correction software
Several brands offer solutions to the acoustic problems of your room in the form of software. For example, IK Multimedia with Arc or Reference from Sonarworks.
The principle is as follows: you measure your room with a specific microphone, the software analyzes this response and corrects the sound coming from your speakers by applying a filter (frequency correction, phase correction…).
On paper, it’s a both brilliant and very logical approach.
But can this type of technology really replace proper acoustic treatment?
Not at all, but that doesn’t mean it’s completely useless either.
Let me explain why (and I hope to clarify my response to Jérôme, a reader who asked me some time ago via email: “What do you think of the ARC 2 from IK Multimedia?”):
First of all, one room cannot correspond to a single correction: indeed, depending on your position, the sound changes. For example, start playing a piece of music you know well and move around the room. You will notice that the sound evolves — especially in the bass due to modal resonances.
The fact is that these resonances cause the disappearance of certain specific frequencies, with attenuations that can easily reach -30 dB. This is a lot: it’s impossible to fully correct something so precise.
Finally, software can never correct certain problems such as a reverb time that is too long.
From these observations, it is clear that software solutions like IK Multimedia’s Arc cannot replace real treatment.
However, they are definitely high-end, high-tech tools that will prove very useful for improving the acoustics of a room once the main issues of reflections and modal resonances have been addressed. A bit like a cherry on top of the cake, so to speak… 🙂
To learn more about how these types of tools work, feel free to read, for example, this review of Sonarworks on homelyrecords.com.
To go further…
In summary, here are the main points to remember:
- You can achieve good mixes in a room whose acoustic treatment is not perfect;
- Covering the walls with absorbent panels is a very bad idea;
- Acoustic treatment is just as essential for recording as it is for mixing or mastering;
- Egg cartons on the walls do not work
- Software solutions like IK Multimedia’s Arc are not enough to correct a room’s acoustics.
And if you want to go further in improving the acoustics of your (home) studio but don’t quite know where to start, check out my Acoustic Treatment Guide. It condenses all the necessary information 😉
I also recommend the training “Acoustic Solutions for the Musician, Sound Engineer, and Music Lover” from SawUp, which is just THE reference training on the subject.