How to achieve better vocal recordings: room acoustics

August 15, 2018

On one hand, laying down vocals is simply a matter of hitting ‘record’, doing your thing, and relying on the power of technology to capture your voice (musical or otherwise) in all its glory. On the other, laying down vocals is an endless gauntlet of fine-tuning and troubleshooting and fiddling with software and shouting profanities at your equipment and… well, you get the picture. Those with experience recording vocals will know all too well the struggle of getting recordings ‘just right’ – the process can be puzzling, and it’s certainly not as easy as ‘just hitting record’.

Luckily, there are a number of practical steps you can take to improve your recording game, allowing you to produce squeaky clean vocals that sit nicely in the mix every time. In this post, we will look at an often overlooked part of the process of recording vocals: room acoustics.

What are room acoustics?

To get the best out of your vocals you need to step back and consider the space around you. Before your voice slides down a microphone wire and crystallises into a series of digital signals, it is first influenced by a number of environmental factors. These factors make up the acoustics of the room and they determine the amount of reverb and delay present in your final recording. Intuitively, vocals recorded in a small padded closet will sound vastly different to vocals recorded in a large room with the windows open. As such, you will need to choose (and perhaps design) a space which is suited to capturing vocal recordings that tick all the right boxes.

Bad acoustics can lead to problems in your recording that cannot simply be “fixed in the mix” – rather than simply treating the symptoms, you need to tackle these problems at the root by making changes to your recording space. Your goal is to eliminate any disruptive room noise and prevent the sound of your voice from bouncing off surfaces and re-entering the microphone. These ‘reflections’ of sound can prevent you from capturing the most pure version of your voice. Room reflections are influenced by the size of the room, the positioning and texture of the walls, and the material of surrounding surfaces. In a home studio, we recommend that you give the room in which you intend to record some acoustic treatment to control any unwanted reflections.

Sound treating a room for recording

The classic DIY vocal booth comprises a pokey closet with mattresses leaning against each wall and a mic stand placed in the middle – some brave souls have even been known to use a shower cubicle to a similar effect. Small spaces such as these generate better vocal sounds, giving recordings a dampened sound with little interference. However, we would suggest that you invest in some proper acoustic treatments to get the most professional-sounding results. The main types of room treatment on the market are as follows (before making a purchase, be sure to do your own research to establish that a given treatment is suited to your needs):

  • Reflection Panels: These are thin absorbing panels that are attached vertically to walls, preventing mid-to-high frequencies from reflecting and mitigating slap echo in the room. Although they result in a cleaner sound, they do not completely eliminate reverberation.
  • Diffuser Panels: Rather than absorbing sound like many panels, these panels work to diffuse and scarrer sound waves. This has the effect of reducing echo and interference. They’re best used on front and back walls with some distance from the sound source. Oh, and they also tend to look very cool compared to your average acoustic panel.
  • Bass Traps: These come in the form of absorbers, usually made of foam or fibreglass, that are designed to remove unwanted lower frequencies and eliminate flutter echo. These treatments are usually placed in the corners of a room to give them more depth.
  • Ceiling Clouds: These are acoustic panels which are mounted or hung from the ceiling, in a horizontal position, in order to reduce natural reflections of sound from above.

What kind of space do you need?

In order to capture the cleanest vocal recordings, you are better off using a smaller space. Larger rooms are best reserved for recordings of instrumentation and live band performances – in these contexts, a slight acoustic footprint is preferable as it makes for a more robust sound. However, vocal recordings should be pure, unmuddied by reflections and echo. In other words, your primary aim is to capture the raw signal with the smallest acoustic footprint possible (especially with podcast or voiceover recordings). Smaller spaces produce less echos, delays, reflections and flutters compared to larger spaces, allowing them to function as a ‘blank canvas’ for your vocal recordings. Remember, vocal effects and reverb can all be added with your DAW. Ultimately, your best bet is to locate a small space and repurpose it as a makeshift vocal booth (although we know this may not always be possible – we’ll get to this later). As we said above, many people find that closets are a good starting point for home recordings.

Acoustic treatment for vocal recordings

If you have access to a small enclosed space, you now need to give it some acoustic treatment. As a rule of thumb, you should aim to treat between half and three quarters of the surface area; too little will result in acoustic interference, whereas too much will result in dry vocal recordings. Cover each wall (and preferably the ceiling) with reflection panels of medium-level thickness, and ideally made of rigid fibreglass rather than foam. While some foam panels are effective, they are less capable of absorbing lower frequencies and leave you with the arduous task of removing unwanted bass frequencies with EQ. It’s always best to play it safe and buy your acoustic treatments from trusted vendors who develop products on the basis of research, development and extensive testing. We’ll leave you to go out and do your own research here – but trust us, there are plenty of great brands to choose from!

Most vocal booths also make use of bass traps to more effectively absorb the lower frequencies (i.e. frequencies which are not as easily absorbed by standard reflection panels). Being thicker, bass traps usually need to be placed in the corner of the booth where they are given more depth – the result is an environment in which the bass in your voice does not become muddied, leaving you with a recording that is clean from top to bottom. Of course, this all depends on the quality and functionality of your bass traps: cheaper treatments bought off Amazon Prime always run the risk of being too porous to actually ‘trap’ any soundwaves. So we’ll say it again: do your research, figure out your requirements, read plenty of reviews, and you can’t go wrong.

Now, if you don’t have an appropriately small space in which to build a makeshift vocal booth, fear not… there are alternatives that don’t involve emptying out an old closet and padding it with layers of oddly-shaped wallpaper! Once of the most effective ways of treating a larger room for better vocal recordings is with the use of a reflection filter. This is essentially a small shield made of acoustic treatment panels that attaches to your stand and prevents reflections from making their way back to your microphone. Sure, it may be a quick fix and it may not guarantee the same crystal-clear results as a fully-treated booth. But given its simplicity and affordability, the results are more than good enough. Plus, any unwanted acoustic effects that your recording does pick up can easily be removed in the mix. A slightly more sophisticated acoustic treatment would involve closing off a section of your room by putting up a series of large acoustic baffles. However, despite covering an increased surface area and replicating the effects of a full booth, the ordinary consumer should be warned that this set up will come at a higher price!

Our London recording studio offers a range of vintage and modern gear and the expertise of veteran producer, George Apsion. We ensure that sessions always brings out the best in every client.

If you like what you hear, please get in touch to book some time in our studio for vocal recordings. Keep your eyes peeled for part two of this blog series on the vocal recording process. Next up, we consider the recording equipment necessary to get the most out of your angelic voice.