“No need to buy sound-absorbing 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, above all, 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 the bad practices. That is, the “common sayings” that don’t contribute much to the acoustics of (home) studios, or even disrupt 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 is often read on forums that without acoustic treatment or if it is not 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 option to use headphones for mixing. Sure, 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 quieter 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.
Of course, it’s better to mix in a room with partial acoustic treatment than nothing at all. But even if it’s not perfect, it’s 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 must be sound-absorbing 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 often 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.
You 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 sound-absorbing 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 recording, that is to say, for the recording phases also called tracking.
That’s true, after all: it’s at this moment that the room’s resonances are most noticeable, since the microphones capture the natural reverb of the room. If this 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 studio monitors, acoustic treatment is essential to truly benefit from their qualities! 🙂
4. Egg cartons, carpets, mattresses…
I’m returning to my introductory example in this article.
Acoustic treatment can be quite expensive, and it’s 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 absorption 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 is not just about covering the walls with somewhat absorbent materials.
First of all, the amount of material matters a lot: 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 that egg cartons can replace mineral wool or acoustic foams for studios come from?
In fact, egg cartons (and carpets, for example) do absorb a bit. But only in the high frequencies, to which we are quite sensitive. This is what we see in the graph below, where a high absorption coefficient indicates a better ability to absorb a sound wave:
Result: it seems better, but in the end the room is still not balanced since only 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 an acoustic correction software
A number of brands offer solutions to your room’s acoustic problems 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 both a 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.
I explain to you why (and I hope to clarify more clearly for Jérôme, a reader who asked me some time ago by email: “What do you think of the ARC 2 from IK Multimedia?”):
First of all, a room cannot correspond to a unique correction: indeed, depending on your position, the sound changes. For example, start playing a piece of music that 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 is impossible to fully correct something so precise.
Finally, software will never be able to correct certain problems such as a too long reverb time.
From these observations, it is clear that software solutions like the Arc from IK Multimedia cannot replace real treatment.
However, they are clearly high-end, high-tech tools that will prove very useful for improving the acoustics of a room once the main problems of reflections and modal resonances have been addressed. A bit like a cherry on the cake, in a way… 🙂
To learn more about how this type of tool works, 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:
- Good mixes can be achieved 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 the Arc from IK Multimedia are not enough to correct the acoustics of a room.
And if you want to go further in improving the acoustics of your (home) studio but don’t know where to start, head over to 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.