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Recording in a noisy room
Getting good audio when recording in a noisy room can be a problem, especially if it is a public space. But you will get a much better recording if you use a cardioid microphone, get as close to the talent as possible and avoid pointing the mic at obvious noise sources
- Use an external microphone but NOT one that is attached to or next to your camera
- Get the microphone as close to your talent’s mouth
- If the room isn’t too noisy try using a shotgun mic
- In a medium noisy room try a lavalier or clip mic
- In noisier rooms use a handheld interview mic, such as a dynamic cardioid or super-cardioid microphones
- Point directional microphones at your talent in a way that avoids noise sources
- If all else fails, clean up your recording with a de-noise tool
First, let me explain what I mean by an external microphone in the context of recording in a noisy environment.
Although many video cameras, DSLRs, and smartphones have built-in internal microphones an external microphone will usually give you much better audio quality.
Strictly speaking, any microphone that plugs into your camera is an external microphone. However, having an external microphone that sits on or next to your camera will not necessarily give you great audio, although it may be an improvement on the built-in camera microphone.
External microphones on your camera, like the Rode VideoMic on this DSLR, maybe an improvement over the camera’s internal mic, but they are not the solution to recording in a noisy room. You need to get the microphone away from the camera and close to your talent.
Conventions and trade shows are noisy events. In the example above Andrew from Hashtag-Events is using a handheld cardioid radio mic and is being filmed on a smartphone.
The proximity of the microphone to his mouth ensures his voice is much louder than the crowd noise in the hall. The audio and video recordings will be synced in the video editor.
Good sounding audio is frequently a result of getting the microphone as close to your talent as possible.
When using a camera’s internal microphone there will be times you do not want to get close up to your talent because the composition of the shot may be completely wrong. With an external microphone, you are free to compose the shot the way you want it while still being able to record good quality sound
In this set up I was recording interviews with my Canon XF100 and wanted to blur out the tiny wrinkles on the collapsible backdrop. This would be easy to do with a fast lens on a DSLR but is harder to do with the zoom lens on a video camera.
To get the effect, I had to zoom in using the XF100 that was 13ft (4m) from the interviewee. The speaker was in focus but the background was nicely blurred. For more details of this technique see my article on using depth of field to remove muslin backdrop wrinkles.
In such circumstances, the internal microphones on the Canon video camera would be too far from the subject to record good audio. However, the external microphone above and in front of the interviewee captured the voice perfectly.
Although this room was reasonably quiet, under noisy room conditions an external microphone is important for recording good audio because it can get close to the talent. The closer you can place the microphone to the talent the better.
Although shotgun microphones are often used for outdoor recordings, I have had a great deal of success with a Sennheiser ME66 in noisy environments.
The ME66 is a condenser shotgun mic with a super-cardioid pickup pattern, so it rejects sounds that are off-axis. However, if the room produces an echo or reverberation, my ME66 recordings have needed post-processing to remove or reduce the reverberation.
A microphone that has worked well under the same conditions is the Samson CO2 pencil condenser microphone. It also has a super-cardioid pickup pattern and is much cheaper than the Sennheiser.
Position the microphone so that your talent is on-axis but the room noise is off to the side or behind the microphone. Having the microphone above (as in the previous image) or below the talent normally works well.
To record good quality audio I placed a directional microphone as close to the talent as possible while keeping it out of frame. Normally I attach the shotgun mic to a boom stand and have the microphone above the talent.
However, if the ceiling is relatively low and has acoustic ceiling tiles I will lower the mic stand and have the boom arm down by the floor, with the microphone point up and towards the talent’s face.
If you do not have a microphone stand available use let the talent hold the microphone just out of shot and pointing up towards their mouth. If possible, have the microphone on a pistol grip with shock mount it should.
The beauty of lavalier microphones is that they can get very close to your talent’s while remaining quite discrete. Most lavalier mics have sub-miniature microphone capsules, so although they are not invisible they are pretty small.
Most lavalier microphones are omnidirectional, meaning they will record sound equally from all directions. Initially, you may wonder why you would use an omnidirectional mic when recording in a noisy room
When you reduce the gain to bring the voice back to a normal level you’ll also reduce the noise level. Although the room noise has not gone away the voice will be clearly above the background room noise.
Typical omnidirectional lavalier microphones for use in video production include the Sennheiser ME2 if you want to spend a bit more, or the Audio Technica ATR3350 or MOVO LV1 at the budget end of the price scale.
When miking the talent the microphone capsule is placed about 6 to 10 inches (15cm to 25cm) from their mouth. This can be on a tie, jacket lapel, or neckline of a T-shirt, dress or blouse. If you wish to hide a lavalier microphone the mic capsule can be placed beneath light clothing.
A good example of a cardioid lavalier microphone would be the Sennheiser ME 4. Because of the tighter pickup pattern, it would work well in noisy conditions. Watch out for large movements of the talent’s head that may cause their voice level to appear to rise and fall.
A handheld dynamic cardioid microphone is frequently used as a vocal or reporter microphone. A handheld mics I have used in noisy environments is the Audio Technica PRO 31 (now updated to a PRO 41) and the Shure PG58. Both look very similar to the popular Shure SM58 but are cheaper. All of these mics are normally used for close-up vocals but can also be used for voice recording in a noisy room.
The mics are directional
If you require even more rejection of off-axis sound you could opt for a super-cardioid microphone. However, such a mic would be more difficult to use in an interview situation.
A typical cardioid dynamic handheld mic for noisy environments would be the Shure SM58. It is probably the worlds most popular live vocal microphone and is very robust. Cardioid mics are frequently used for vocals, street interviews, and red carpet events.
Hear how much background noise the Coles 4104b and Shure SM58 reject in Mike Delgaudio’s video. Mike has set up the two mics in front of a construction site with a noise level of 70-80dB A. You’ll be amazed at how well both mics reject background noise.
Examples of super cardioid microphones would include the Aperture Deity, Sennheiser ME66 and Samsom CO2. Super-cardioid mics are frequently used to record dialogue on film and television sets. They are useful when you want to “zoom in” on the dialogue without capturing the nearby sound. So super-cardioids would be good when recording at sporting events, business shows, and conventions.
If you are using a directional microphone think about how you are going to point it towards your talent. If they are standing a few feet in front of a noise source, don’t point the microphone horizontally at them. By doing so you will also be pointing your directional microphone at the noise source.
In such circumstances, point the mic down from above the subject, or up from below. This is because fewer noise sources are likely to be above or below your speaker.
However, watch out for ceiling mounted air conditioning vents that could be a noise source. Your best bet is to do a test and determine the best way to angle your microphone.
Another concern about how you point your microphone at your speaker is the pickup pattern of your microphone. When using a shotgun, super cardioid or hyper cardioid microphone it may also pick up some sound from the rear. When this is the case you obviously do not want a noise source behind your microphone.
If you are unsure of the pickup pattern of your microphone check the documentation that came with it. Many microphones will show a small graphic on their body of their pickup pattern.
The image below is of my Samson C02 microphone, showing a super-cardioid polar pickup pattern printed on its side. Although this microphone will pick up most of the sound from in front it will also pick up a small amount of sound from the rear. For more details about microphone polar pick up patterns check out this article.
De-noise your recording
Although the above techniques will help you reduce the amount of room noise in your recording, you probably will not eliminate all of it.
If you need your audio to be as noise free as possible you can try processing your recordings in your favorite digital audio workstation (DAW). For instance, Adobe Audition has some built-in tools you can use but there are a number of plugins you can also try
The one I am particularly impressed by is iZtope’s RX7 for Post. Check out the Dialogue Isolate and De-Rustle tools from RX7 on the iZotope website. iZotope have introduced AI into their RX7 audio repair tools and they do a fantastic job, but the full software is not cheap.
A cheaper alternative is to use RX Elements. When I last looked it cost $129, however it was $29 in their Christmas/New Year sale. RX Elements includes De-Click, De-Clip, De-Hum and Voice De-Noise elements from their full package. You can install them as VST plugins or use the RX Editor, that’s included in the purchase
Open your audio in the RX Editor. If your camera produce mp4 or Quicktime files you should be able to open them directly. You can then use the Voice De-Noise option manually.
An easier way to repair your audio is to to use the built-in AI. Click on Repair Assistant in the top right corner and choose the type of material you wish to clean up. The options are Dialogue, Music, and Other. Choose Dialogue and then Start Analysis. The software will produce three repair preview (light, medium and heavy). Choose the one that you like the most and then render the repair.
If you do not want to splash out on RX Elements and have access to Adobe Audition, try the included noise reduction filters. A totally free alternative is Audacity. Go to the Effects menu and use the Noise Reduction plugin. The results may not be as good as you will get in RX Elements, but at least the software is free.
Can you get too close to the microphone?
The answer depends on…
- The sound style you are aiming for
- Do you mind if the microphone
appearin the shot
- What type of microphone you are using
Some microphones exhibit what is known as a proximity effect. This is where low frequencies are accentuated when you get right up to the microphone. This is often exploited by radio presenters, announcers, and vocalists.
As Neumann says of the proximity effect, “You can use it to make things big, fat and sexy”. That is why the proximity effect is frequently thought of as being something desirable by voice over artists. But it does not necessarily sound natural and can make the voice sound “muddy”.
Furthermore, a close-mic technique is not easy to maintain on camera without it looking as if you are having a love affair with the microphone.
You could use the proximity effect to your advantage if you have a voice booth and intend to record a voiceover. It may also apply if you are going to be presenting from behind a desk with a large diaphragm microphone clearly in shot
Here is an example of the proximity effect on a Samson C02 super-cardioid microphone, with speech record at about 5-6 inches and 12 inches from the microphone.
However, when recording a piece-to-camera, or interviews, the proximity effect is unlikely to be a feature of your videos.
The proximity effect is typically associated with directional microphones. However, directional microphones like the Electro-Voice RE20 can compensate for the proximity effect and eliminate it. The RE20 achieves this through the use of their Variable-D™ technology. Essentially this uses multiple slots cut into the side of the microphone body.
Apparently high frequencies enter nearest to the microphone’s diaphragm. Mid frequencies enter about halfway down the microphone body. Finally, lower frequencies enter farthest from the diaphragm. The result is that the proximity effect is eliminated.
Some mics tackle the proximity effect by including a high pass switch that rolls off bass frequencies. This can also help reduce low-frequency rumble from nearby sound sources, such as roads and industrial plants.