Room Tone is the atmos or ambiance of a location. It is the sound of that location when there is no direct input from any props or people. This does not necessarily mean the sound of something prominent, like the buzzing of a fridge, nor does it mean complete silence; it is only the natural sound of the location, which is often very quiet.
Room Tone is often recorded during the production of podcasts, films, and other similar media. You may be wondering what the purpose of recording it actually is. Essentially, there is never true silence in any environment (except for outer space); there is always some sound. Whatever environment you find yourself in now, it’s guaranteed there is some noise and not 100% silence. Like real life, there should never be any true silence in a podcast or film, as these sections of complete silence will come across as jarring.
This is one of the main reasons recording Room Tone is necessary, to be available in the postproduction stage, which has a range of uses for allowing more freedom for the editor, which can result in the creation of a higher-quality sounding piece.
Even if you did somehow find yourself in a place of complete silence, recording a Room Tone will not necessarily result in complete silence. Examples for why this occurs could be due to the electrical noise that is picked up from a preamp or microphone self-noise. If you would like to learn more, the Noise Floor, which is typically a part of room tone, and these examples and others are discussed in more detail within this previous article.
Table of Contents
How to Use Room Tone
Room Tone has some main applications; filling in large audio gaps, smoothing audio, and noise reduction.
Filling in large audio gaps using Room Tone comes in useful for a range of scenarios. For example, imagine you are recording a simple scene where two main actors are shown walking into a room and they begin talking.
In the editing stage, an issue becomes apparent; the editor thinks there should be an establishing shot of the room before the two main actors are shown entering and talking, because without it is not clear that they are in a location that is important for the narrative of the story.
Fortunately, the editor can use a shot of the room from a different scene and it works perfectly for an establishing shot. However, no audio was recorded for the establishing shot, as the shot was used in a sequence that features only music, so it was deemed unnecessary to record any audio at the time of filming.
The editor realizes that it appears jarring how there is complete silence before the next shot where we hear the two main actors talking to one another. The editor considers using music to cover-up the silence but is following strict instruction from the director to not use music at all in this scene.
Luckily, a Room Tone has been recorded for the space and is placed to play alongside the establishing shot in the edit. It works perfectly to show the establishing shot and there is no sudden noise that becomes apparent in the next shot.
This is just a single example of where Room Tone is useful for filling in large gaps of audio, but there are many more situations where more freedom can be given to improve the quality of a piece.
In podcasting, it is less likely you will be using Room Tone for reasons like this. But Room Tone is extremely useful in podcasting for the remaining applications I will be discussing.
Room Tone can be used for smoothing audio in many scenarios. I find that the most useful is for replacing gaps in audio created by the removal of coughs, breathes, or similar unwanted sounds. Placing a Room Tone recording where there is an audio cut from the original recording of the dialogue can hide the fades and cuts in the dialogue audio. Not using Room Tone for these gaps creates a noticeable area of silence that it will make your audio come across as less professional, as there will be a noticeable absence of sound.
Room Tone can also be used for capturing a noise profile. A noise profile is essentially a way of capturing the unwanted background noise (or Noise Floor) that is audible in your recordings in a way that can be interpreted by your DAW.
Capturing a noise profile means that it will be easier to remove any background noise in any recordings, such as dialogue or sound effects. Some DAWs have automatic tools that use the noise floor information to remove the noise from a recording. A Room Tone provides more data than a few seconds of background noise taken from a recording can offer, so is more likely to create a better result, and in my experience is extremely effective for reducing background noise.
How to Record Room Tone
Recording Room Tone sounds easy, but in reality, trying to record for a minute straight without anything getting in the way is more challenging than you might think.
Room Tone should be recorded in all main locations where you are recording audio during production. This will allow for the Room Tone to more closely resemble the other audio recordings, which will allow more freedom for the editor.
You should aim to point the microphone in the same direction as when you were recording your production audio. I’ve seen boom operators on film sets recording Room Tone and they’re pointing the microphone in a completely different direction to when they were recording the main audio. The Room Tone recording will be different from the main audio because of the level change caused by varying reflections in different parts of the room.
Additionally, if an actor is recorded away from a sound source, like a buzzing fridge, you do not want to record audio with the microphone pointed at the fridge! Even if it is in the same room, the Room Tone will be very different!
I’d recommend you record Room Tone for at least 30 seconds. Of course, the more Room Tone available, the better. You could record up to two minutes if you really wanted; again, it can give more freedom to the editor.
Whatever you can record, even if it is just 30 seconds, should then be listened back to at an increased level. Doing this will let you know if there are any unwanted irregular noises in the recording. Keeping these irregular noises in the Room Tone recording, like a distant car horn or a Fly buzzing close to the microphone, might be noticed and break immersion, especially if that portion of the Room Tone is frequently used.
Always ensure that everyone during production is aware that you will be recording Room Tone. Try to let them know in advance if possible. On a film set, there will be a shooting schedule where you should aim to have a few minutes available to record Room Tone. The crew will not be happy if you request at the time of production that you need to record some Room Tone, you might be changing the schedule, and this will create stress for the crew.
If you only have a short amount of time available to record Room Tone, I would recommend you record it once the main production has ended. This way, you will have a clear understanding of all the microphone placements and positions, so will know where to record. Recording after production can be challenging however, as the production process, especially for films, is grueling. Many of the crew will be eager to get home and keeping everyone from dismantling equipment and packing equipment will be difficult!
Recording Room Tone after production also means that you will roughly know the gain levels used during recording. Keeping the gain at the same level during the recording of the Room Tone will mean it will be less likely that the gain needs to be adjusted during the editing phase.
Room Tone could be recorded before the main production begins. Obviously, this will mean that if you have to change the positioning of microphone placements during recording that your Room Tone will not match as nicely due to your Room Tone being recorded in different positions and locations within the room. You are more likely to get a quieter crew, however, and I’ve known some directors and producers to prefer recording Room Tone here to calm the crew down before the main production begins.
In my experience, you should allow for more time to record Air Tone. This is basically Room Tone but outside. I have found this more challenging to record in the past. When you’re indoors, closing windows and doors can eliminate a lot of noise. You can’t do this outdoors; a plane flying overhead, a dog barking, or an Ice Cream Van driving past can cost you minutes, so extra time for Air Tone will ensure you can capture something usable.
If you forget to record Room Tone or are unable to, you might be able to find a small portion of silence during recording in the main production that could be used instead. This could be a large pause between dialogue, for example, or the pre and post silence when recording sound effects.
Doing this can achieve the same effect as standard Room Tone, but is more likely to contain noises, may not be long enough in duration for the desired use, and might be noticeable if repeated. You could loop it to make it usable on a longer section, but the effects of containing noises and the noticeability of its repetition may still be an issue.
Step-by-Step: Room Tone for Filling in Large Audio Gaps
This will be the easiest of the three step-by-step instructions shown and is a really simple use of Room Tone. I’ll be using it for filling in the audio for the example scenario discussed previously, where an establishing shot is added. Although this step-by-step is best suited for media that uses video, it can still come in handy for podcasts that also feature video. Despite its lack of video capabilities, I’ll use Audacity for demonstration purposes, as Audacity is similar to most DAWs.
The image below shows Dialogue A and Dialogue B, which is all the main dialogue for this scene. There is an empty gap of 5 seconds before the dialogue begins, this is because the establishing shot that the editor has added will feature in this space.
To fix the gap of silence, Room Tone will be added. Drag the audio clip for the recorded Room Tone into Audacity. This will add it to a new track.
As you can see, the Room Tone is one minute in length, so will need to be cut down to be 5 seconds long. From the point 5 seconds into the Room Tone audio, click and drag to the end of the clip until the remainder of the audio is highlighted in blue.
Pressing Backspace will delete this section of audio, leaving just 5 seconds at the start.
Although less jarring than if we hadn’t included Room Tone, listening back to the audio we now have will still result in a noticeable change in the cut between the Room Tone and the dialogue.
This is because the background noise in Dialogue A and Dialogue B has been combined, meaning the level has increased to a level higher than the Room Tone. Typically, if you combine two audio signals that are the same, there will roughly be a 6 dB increase. Increasing two audio signals that are not the same will result in roughly a 3 dB increase.
I was expecting to have to increase the gain of the Room Tone by 6 dB to make up for this, as I thought the background noise would be similar for both dialogues as they were recorded in roughly the same position and microphone orientation, but it turns out that the noise wasn’t similar enough, so I ended up increasing the dB by only 3 to match the level.
Step-by-Step: Room Tone for Noise Reduction
In the above Step-by-Step, I increased the Room Tone to match the levels of the dialogue. This may not always be the best option, as I have just increased the amount of background noise.
To fix this, the Room Tone can be utilized to create a noise profile to reduce the amount of background noise within the scene, as discussed previously. This is also useful for cleaning up sound effects.
First, let’s start with the same audio files used previously; two dialogue tracks and one minute of Room Tone.
Highlight the Room Tone track by double-clicking it. The longer the Room Tone, the more information there is available that be can be used to create a more detailed noise profile.
Next, select “Effect” from the top of the screen and then “Noise Reduction…”
This will open the Noise Reduction window. Select “Get Noise Profile” and the window will close.
Next, select Dialogue A by double-clicking the audio and then open the Noise Reduction tool again.
There should now be a Noise Profile based on the Room Tone. Pressing “OK” will apply the noise reduction to Dialogue A. Do the same for Dialogue B to remove the noise on both tracks.
You may think that removing the Room Tone track will now make sense, as it isn’t necessary anymore to match the audio from the establishing shot to the dialogue. However, the silence will be unnatural to listeners, so I’d recommend you reduce the gain on the Room Tone so that it is only barely audible.
Step-by-Step: Room Tone for Smoothing Audio
It is more likely that you will be editing out all unwanted noises in a recording. A piece of dialogue in your DAW is more likely to look like the screenshot below, especially if it is dialogue for a film.
The sudden drops to silence will be noticeable, so Room Tone needs to be added. I’ll show you how to place Room Tone in the gap between approximately 17 and 18 seconds. On the Room Tone track, drag the audio up to 17 seconds by selecting the Time Shift Tool shown below.
Then, highlight the remainder of the track from 18 seconds onward and press Backspace to delete that portion of Room Tone, leaving only the section that fills the gap.
This Room Tone worked in the silence gap nicely. However, sometimes the Room Tone will sound slightly different to the background noise in the dialogue. To fix this, you can first make the Room Tone slightly longer, like below.
Then, press the Envelope Tool in the Cursor Tools section at the top of Audacity. This will allow you to automate fade-in and fade-out of the audio.
You can then select the waveform to add a fade-in at the start and fade-out at the end of the Room Tone, making the transition much smoother.
In other DAWs where a crossfade can be easily applied, I’d recommend utilizing it, as you can simply place the Room Tone sample between two pieces of audio where there is a gap and have the Room Tone fade in and out automatically. Where crossfade isn’t available, you can also create an even smoother transition by fading out and in the dialogue that surrounds the Room Tone. Take a look at this video to see how easily Room Tone can be added in a video editor.