- Posted: 14/03/25
Small Studio Acoustic Design
Welcome! The First installment in the Signal Path Series (referred to as “SPS” from here throughout) begins a journey that we are taking here at mixrevu.com to improve the home recording studio mix environment and mix process. We are looking to learn a lot, and inform others along the way; after all, we are a community based around novice engineers and student engineers.
If you go to any forum, blog or magazine website based around pro audio you will find questions upon questions from student engineers, as well as, novice pro engineers asking about the many ways to improve your home recording studio setup. Since this question is one of the most asked, (and probably most misunderstood) we decided to tackle the home recording studio mixing process in a step-by-step series. We are going to chase the audio signal through the (mixing) signal path and illustrate what we can improve on at each stop along the way!
If you are reading this article first, then I hope you jump aboard for the ride. We are just getting started. If you don’t start with us on the first leg that’s ok too, we are going to travel along with the signal and you can join anytime to learn with us as we seek to improve our mixes at every turn!
What are the major ways I can improve the sound of the records that I mix?
What areas of my studio should I improve on to help me analyze my mixes better?
Questions like these are the reason the first topic of the SPS is based around Recording Studio Design. I quote:
“If you can’t take your room out of the mix, you can’t take your mix out of the room”
There is a reason that if you Google “Small Studio Acoustic Design” you will get a plethora of articles. Small rooms (esp. square bedrooms) come with inherent challenges that large custom built studio control rooms don’t suffer from, and so it is imperative that engineers mixing in small rooms (I’m raising my hand too) look to control our room deficiencies as a major part of our "mix room readiness". This article isn’t about pontificating about why you should or shouldn’t mix in a small room, because the fact of the matter is, many of us don’t have a large amount of choices. In this article we will focus on getting the information that will help us, at least to some extent, get “control” of our control room (pun intended).
Mission: Learn how to make your small studio the best listening environment it can be…
Just to clarify before we get into the weeds, your small home recording studio design is going to be different, in many ways, than your home studio listening environment because the recording space is propagated on the recording of the sound source and how it reacts with the room it is being recording in, The control room/listening environment is determined by the reaction between the monitors and the room the sound is being reproduced in. It’s important to make a note that this article is focused on the control room dynamics and how it works well or not so well with your playback monitors.
What are we dealing with in a playback environment?
- Direct sound
- Indirect Sound
- Frequency response
- Room Modal resonances / Low Frequency Reproduction
For any mixing engineer it is important that we are aware of all of these factors in how our room reacts to playback from our monitors. Let’s just take a short detour to define each of these terms before we illustrate how they affect our ears and what information our ears receive.
-Direct Sound- sound coming from the monitors (i.e. what we are trying to hear)
-Indirect Sound-Sound reflections that we receive from objects in the room including walls and anything else sound can reflect off.
-Frequency Response-This exposes where your rooms sensitivities are. You may find that your room is especially sensitive at a certain frequency, and that in turn will need to be a “mental note” for your subsequent mixes.
-Room Modal Resonances-This is tied very much to the Frequency response. Most room modes are in the 1st -4th octave (31-250Hz) range and these fundamentals and their multiples can propagate in certain parts of your room i.e. certain frequencies may dissipate at a lower rate in the corner than they do in other parts of the room so you will notice a “boost” of that frequency in your corner.
-Low frequency reproduction-Large control rooms tend to be able to reproduce low frequencies more efficiently than smaller rooms and this is where many small control rooms have trouble. In some instances these low frequencies can cause resonance node issues that can cripple mixing in a small room. With low frequencies the wavelengths are so long that many times an expanded room size coupled with sufficient bass traps and absorption is required to mix properly.
So, let’s cut to the chase, how do we handle these major issues in a small home recording studio environment? I’ve only had the pleasure of being involved in a few studio setups from the outset, so I am only somewhat familiar with accomplishing this task. I've had the same questions while looking for “key ingredients” to take from setup to setup wherever I go. Much of the knowledge that I gained in research for this article can be credited to the F. Alton Everest and Ken C. Pohlmann book “Master of Acoustics” and my avid reading of Sound on Sound articles along with a nifty Acoustical Physics paper by UIUC, check the sources list at the end for more information.
Making the most of direct sound- If you have read the masterful book by F. Alton Everest and Ken C. Pohlmann (Master Handbook of Acoustics) or had the pleasure of going to any major studio you’ll notice the term or maybe just the results of trihedral design. This design is based on the desire to create the RFZ (as illustrated in Chapter 20 of the Everest, Pohlmann book) “Reflection Free Zone”. This is established to create a wide “sweet spot” that is free from early reflections for the mixing engineer. I don’t want to delve too much in to this, but this is a largely used alternative to what many small rooms use to manage direct and indirect sound called the LEDE (Live End-Dead End) room. To learn more about how large studios use trihedral design to accomplish the “RFZ”, check out the Everest/Pohlmann book.
The vast majority of small rooms will utilize the LEDE approach so let’s delve into more about how that works. In a small room we need to determine what side of the room our playback is coming from. Whatever side of the room that is, the wall behind it can be set as the dead end and the wall behind the mix engineer shall be set as the live end. (Just as a quick note) If you have a more rectangular room it’s generally better to set yourself along the longest path of the room so that your monitor’s sound has the longest possible length to travel. Once we have our live end and dead end established we should set our monitors on axis with our mixing position and free from the neighboring walls (this is in a near-field monitoring situation). With my current monitors I tend to like the horizontal orientation, but that decision is personal and based on your situation, and how you prefer your monitors. As long as you have set your volume and distance suitable to clearly hear direct unabated sound from your monitors in a comfortable “sweet spot” for mixing you have your direct sound set. Look to base your head at the “top” position of an equilateral triangle with your monitors being the other axis’s.
Indirect Sound is directly related to the previous paragraph. Indirect sound as defined above is the reflection you get from around your room. Major factors in your indirect sound will be your mixing desk, your console (if you have one), the walls, floor and any other objects. Our main objective when dealing with indirect sound in the control room is to minimize if not eliminate early reflections. Early reflections (some less than 1-5ms) can cloud what we perceive as direct sound. The human ear only distinguishes sounds as separate at a certain time frame. Early reflections that are shorter in length then that time frame are heard as comb-filtered parts of the direct sound. For instance, while in your control room a reflection from your mixing desk gets blended with what the actual loudspeaker is sending you, and your judgment of the sound may be clouded. This is the reason to setup the wall behind your playback monitors to be deadened so that you minimize the closest propagators of early reflections. After you have minimized your early reflections with diffusers
(Auralex Roominator Pro Plus)
additional indirect sound comes from your live end of your room where you have placed your diffuser (one of your diffusers goes on the wall behind the mix position). Your diffusers help to eliminate specular reflections, which reflect back in the same angle that they are produced. Your diffusers will disperse these reflections throughout the room and ultimately allow these reflections to reach your ear in a time frame where you hear these reflections as completely separate from the direct sound. In general this sound will be heard as room ambience.
Your Room’s Frequency Response can be measured in many different ways. There are a few filter sweep CD’s you can buy or perform them yourself on your monitors to see if and when your room resonates at certain frequencies. You may want to make a note if your window jitters at a certain frequency for instance. Low Frequencies are some of the most difficult to manage in a small room and not only would you want to make a note of any resonances of the fundamental in your room but in addition it is wise to be aware of the multiples of that frequency when it comes to compensating in your mix. After knowing the frequencies that are problem areas, your first tactic should be to use absorption and diffraction to diminish the problems on the whole.
Room modes are often significant issues with small control rooms and more so when it comes to their ability to reproduce low frequencies. There are some not so easy ways to measure your room modes, but I have seen a time-energy-frequency analysis used to measure where standing waves occur, and how they interfere with your room’s response. Adding a low frequency diffuser
is a well-established way to disperse this standing energy. You are basically trying to get rid of energy that is propagating irregularly in certain areas of your room to “even out” the low frequency response. Illustrated in the book by Everest & Pohlmann is an equation to take the diagonal of your room and use that to determine the low frequency response of your room. The authors state that anything below that frequency will not be properly supported in your room’s response. Analyzing that determination then gives fodder to the notion that for some rooms, even with acoustic treatment , there may be limits to frequencies the mixing environment can correctly reproduce.
Acoustic Design and Treatment should be one of the first places any mix engineer starts when trying to perfect and improve the sound of their mixes. The mix environment is all about clarity and "truth" coming from your direct sound source so we are aiming to make our room source more neutral in response to our playback material.
Indirect sound management is really the key in a small home recording studio. Deadening the end of your room with absorption and using diffraction in the right areas to keep the live end of your room dispersing waves in a more random fashion.
You should be aware of your room’s frequency response and where its sensitivities are, this will make you better able to compensate for any deficiencies.
Standing waves around room modes are a large part of how capable your room will be in reproducing low frequency content. Diffraction in those areas can help to keep the energy in the room (rooms can be too dead, so don’t go overboard with the absorption) while dispersing those modal resonances so that your bass content is more accurate.
Like I said in the introduction of the SPS, we started with Acoustic design because that’s the basis of any good mix environment. Next up, we delve into the D.A.W. environment and audio processing.
**If you have any comments on this or any other article, catch us in the forum and let’s discuss! **
PS: Just to geek out, my favorite magazine Sound on Sound does a few excellent articles, including some “How to” guides. Check them out if you’d like more information on this topic.
Sources other than my own meager studio design experience: Master Handbook of Acoustics by Everest & Pohlmann, UIUC physics 406 Acoustical Physics of music.