People regularly ask me how to adjust the settings on their audio equipment so they can record the best sound on their productions. It’s a perfectly reasonable question, however, I can never supply the answer they want. I can’t instruct them to turn the gain on their audio recorder to 7, and set the camera input level to 3. Why? The variables will often be different, and where these adjustments need to be set will change. There is no short and sweet answer. What’s needed is real instruction, so, instead of authoring a paid eBook on the topic, I’m going to try to spell it all out in this blog post, using language that camera people can easily understand.
Getting good sound is similar to getting a sharp picture. You have to constantly focus a lens in order to achieve sharp images, and the same is true for sound; you need to attentively adjust the levels on your equipment in order to capture the best sound.
You can use Auto Focus on a camera, however, the downside is the camera will accidentally lose focus on the subject, and immediately stat donrt “hunting” for focus in the middle of a take, which, if you’re trying to create a polished production, looks really unprofessional. Again, the same holds true with sound. You can turn on Automatic Gain Control (AGC) on your recording device, which adjusts the audio levels for you, however, the levels of your recordings will be uneven. When someone starts speaking, the AGC will turn the levels down to avoid peaking and distorting. The moment they stop speaking, the AGC will turn the levels up, and the background sounds will get louder. When the person speaks again, the background will duck down again. The result is very unnatural and distracting sounding.
The thing that makes getting good audio levels difficult is that there’s a very slim threshold in which the audio levels are in the “sweet spot.” It’s similar to how a fast lens with a fully open aperture has a shallow depth of field — you can focus on a subject’s eyes, but the tip of their nose and their ears will both be out of focus. With cameras this is only a concern when you’re shooting with a low maximum aperture. In sound it’s a constant concern.
I don’t want to intimidate you. Adjusting your audio levels is an important responsibility, but it’s rather easy to do. It’s almost as simple as raising or lowering the volume on a TV. You just need to look at your audio meters to be able to judge if you should turn the levels up or down.
Most audio meters are marked by a column or row of numbers. The number 0 should be positioned near the top of the meter, with -6, -12, etc. below it. What do these numbers stand for? Don’t worry about that now! You can learn about that another day. Your goal is to learn how to set proper audio levels for recording. That’s it.
This is the big trick to adjusting audio levels: you need your audio levels to be bouncing between -20 and -12 on your audio meters. The animated meters (the ones that move up and down as sounds get louder and softer) need to dance between the -20 and -12 marks.
The picture above is the screen of a Zoom H4n. The audio in its meter is peaking around -24. This is a little low. The ideal spot is near the halfway point between the -12 and -24 marks, so the operator should turn the input level up a little bit. The problem with recording below -24 is that you won’t get the best signal-to-noise performance out of your recording device. The problem with recording above -12 is that you run the risk of overdriving and distorting. Digital distortion sounds terrible, so it must always be avoided.
Caveat. You knew it was coming. Here we go…
The meters on some recorders aren’t marked with numbers, so you can’t tell where the area between -24 and -12 should be. I’ve seen this on both professional video cameras and portable audio recorders. In these situations, the procedure is a little less scientific. Adjust the audio levels so that the meters dance a little more than halfway up. Do a test recording to make sure the audio isn’t too loud or too faint.
The picture above is the screen of a Tascam DR-40. As you can see, its meter is not marked with numbers like -6, -12, etc. However, on page 50 of its manual, it’s explained that the small inverted triangle on the dotted line above the meter is the -12 mark. The technical term for the inverted triangle is a “hash mark.” Hash marks like these are commonly found on the meters of professional video cameras. Under the word EFFECT on the screen you can see the current Peak Value, which is -23dB in the photo. Again, that is a bit low, so the operator should turn the Input Level up a bit.
Another example of inconsistencies in audio meters is the one on the Roland R-05 portable recorder, which marks 6, 12, 20, etc. Roland simply failed to add the minus sign to these numbers. The meter on the R-05 should read -6, -12, -20, etc., but it does not.
We’re not done. There are several important procedural duties to remember…
1) Prepare for and anticipate loud spikes in volume
When you’re adjusting the level control on your recorder and trying to get the meters to bounce around -12, set it for the loudest sound that’s going to happen during the recording. If you’re recording actors, ask them to say their loudest lines as your adjusting the level. Once you have it at -12, roll it back a little more (actors always get louder when you’re doing an actual take, however, be mindful not to set the recording levels too low). The same rule applies to recording musicians, nature, etc. Anticipate the loudest sound, adjust for it, but don’t go too low.
2) Don’t set it and forget it
Remember: your audio level controls are similar to the focus ring on a lens. Likewise, your audio meters are similar to the viewfinder on a camera. You don’t frame a shot then ignore the viewfinder once you start shooting. It’s the opposite. You look at the viewfinder constantly when you’re shooting. The same holds true for audio meters. It’s important to keep an eye on your meters as you roll. If the sound ends up being louder than you anticipated, you will immediately see your level is over -12, and you’ll be able to make an adjustment as you’re shooting.
“Static noise and other kinds of audio problems look just like good sound on audio meters.”
3) Always use headphones
I know I already used this analogy in my article, but I’m going to do it again: think of headphones as equal in importance to the viewfinder on a camera. Audio meters only tell you what’s happening with your sound visually. They are indispensably important, but they can’t be your only way to keep tabs on your sound. You must have headphones plugged in at all times when you’re recording. They’re mandatory because static noise and other kinds of audio problems look just like good sound on audio meters. You need to actively listen to your audio as you work, period.
In the past I used Sony MDR-7506 headphones, and I liked them a lot, but I recently switched to Senal SMH-1000 headphones. The Senal’s share a lot of the same qualities as the Sony’s, but they have the added benefit of a removable cable, and short and long cables are included. I use the short cable a lot. The long, non-removable cable on the 7506 headphones can be annoying at times.
— SamMallery (@SamMallery) February 11, 2013
The advice in this article is applies to using an external audio recorder with its built-in mics, as well as using external microphones, and line-level signals (such as from a DJ mixer). This advice applies to recording sound directly into a camera, too. It applies to the vast majority of recording situations. Above all, remember: Don’t fear your audio controls! Be calm, apply this advice, and record great sounding stuff! If you found my advice helpful, you can repay me by clicking on my Amazon links before you make a purchase. If you do this, I will receive a tiny commission — at no additional cost to you. Here is some of my favorite audio-for-video gear, with Amazon links for different countries:
Zoom H4n - Amazon USA, Amazon UK, Amazon Germany, Amazon France
Zoom H5 - Amazon USA, Amazon UK, Amazon Germany, Amazon France
Tascam DR-40 - Amazon USA, Amazon UK, Amazon Germany, Amazon France
Tascam DR-70D - Amazon USA, Amazon UK, Amazon Germany, Amazon France
Sennheiser G3 Wireless - Amazon USA, Amazon UK, Amazon France, there are some good bundles at B&H Photo
Sony MDR7506 Headphones - Amazon USA, Amazon UK, Amazon Germany, Amazon France
Senal SMH-1000 Headphones - B&H Photo, Amazon UK, Amazon Germany, Amazon France
Thanks again. Have fun, and remember… -12!