Easy-to-follow video tutorials help you learn software, creative, and business skills.Become a member

Calibrating levels using an SPL meter

From: Audio for Film and Video with Pro Tools

Video: Calibrating levels using an SPL meter

When you are mixing audio for video you might ask yourself, how loud is too loud, how quiet is too quiet? As you are going to send your work out to the world, these are important questions to ask. By properly calibrating your loudspeakers prior to any work you do and leaving the listening volume set the whole time, you will have a baseline volume reference that relates to the outside world. This way you can use your ears to accurately determine when dialogue, effects, or music are too loud or too quiet. As a consequence your mixes will translate to the outside world and they will conform to volume level standards. The tools you will need to calibrate are as follows.

Calibrating levels using an SPL meter

When you are mixing audio for video you might ask yourself, how loud is too loud, how quiet is too quiet? As you are going to send your work out to the world, these are important questions to ask. By properly calibrating your loudspeakers prior to any work you do and leaving the listening volume set the whole time, you will have a baseline volume reference that relates to the outside world. This way you can use your ears to accurately determine when dialogue, effects, or music are too loud or too quiet. As a consequence your mixes will translate to the outside world and they will conform to volume level standards. The tools you will need to calibrate are as follows.

You will need an analog or digital SPL meter. You can get this at your local RadioShack. You'll also need a digital file of pink noise. This is a test tone and you can get this at a web site Blue Sky. They make professional speaker monitors and they actually offer a free bundle of test tones, which is where I got the test tone that we'll use in this lesson. So what is pink noise? Unlike white noise which is randomized noise with energy weighted equally for all frequencies, pink noise is randomized noise with energy weighted equal for all octaves.

Basically pink noise is a test tone that best approximates how we hear. Pro Tools also does have a built-in signal generator that provides pink noise. But some engineers have argued that Pro Tools tone generator isn't randomized enough for the best calibration. So instead we are using here the Blue Sky Pink Noise file which is full bandwidth at -20 decibels Full Scale. And we're using it as an audio file in our tones track. So let's talk about our loudspeakers. I want to look at a slide that shows how they should be arranged physically in your room. This is important.

First of all, you want to make sure that the speakers form an equilateral triangle between the optimum listening position, where you would be, and the speakers themselves and the angles should be 60 degrees at each corner of this triangle. You also want to make sure the tweeters of the speakers are at ear height. That's the best position for them to be vertically. If you have an external mixer or any device between your Pro Tools output and the speakers, you want to make sure that you've calibrated the output levels of Pro Tools and that device. So the way to do this is to use another test tone. This time it's just a 1 kHz sine wave also playing back at -20 decibels Full Scale.

So you have 20 decibels of headroom above this test tone and take a listen to what this sounds like. (Beep) Okay, so we're probably familiar with that kind of tone. You want to play that out of Pro Tools and you want to make sure it's coming out at -20 and you want to set that up so that if your external device, your mixer between Pro Tools and your speaker, is going to have a VU meter or an analog meter. Now remember decibel Full Scale is a digital meter at -20 and that should equal 0 VU on an analog VU meter on your external mixer.

So, you want to adjust your input trim on that mixer until -20 coming out of Pro Tools equals 0 VU, on that mixer between Pro Tools and your speakers. Then we are going to calibrate the actual level of the speaker monitors and for this we would use our pink noise. We want to position the SPL meter where your head would be in the engineer position. Then you want to set the meter to C weighting, slow response. Those are two settings that you'll see on the meter itself.

So C-weighted, slow response. You want to set your tones track to output just to one speaker. We can calibrate each speaker one at a time and then we play the test tone. (Buzzing/white noise) And as it's playing we're going to adjust the output of our speaker up or down to hit in certain SPL levels and once we get there, we're calibrated for that one speaker and we move on to the next speaker. So what are these SPL levels? Let's take a look at a chart and it shows us where we should be hitting.

For a theatrical film work, say you're mixing for a film that's going to play in a movie theater, we listen a little louder as we work in Pro Tools, and if you're working in a very large studio where you are farther away from the speakers or a dub stage for example, you are going to want to calibrate your SPL meter to 85. That's the decibel level dBSPL on the SPL meter. So you play back the pink noise and you adjust the output of the speaker until it reaches 85. Again, if you're working on a theatrical film but you're in a much smaller room, 85 is going to be a way too loud to be listening to for hours on end.

So you're going to want to actually go down to 82 dBSPL, which will give you a loud enough reference but it won't be blowing your ears off. For other type of work such as Internet, TV, broadcast, or even DVD mixing, you're going to be monitoring back at a slightly lower level. This would be 79 for a large studio or dub stage and also 79 or even 78 for a smaller room. Again, remember if you are listening back lower your mixes will tend to be a little bit hotter. It kind of works in the inverse fashion that way.

So these are again just recommended SPL levels, kind of taking a survey across a lot of professionals that I know and work with. These are typical SPL readings that people calibrate their monitors for out in the professional world. So what about audiometers? Within Pro Tools you can use a meter such as the PhaseScope here and it can be a helpful reference to ensure you're in the ballpark but it should only be used as a reference. Truth is that no meter can perfectly tell you all the info that you need all the time. As you can see here on this PhaseScope I'm referencing two things at one time, Peak metering and RMS.

These are two different styles of metering. RMS, which stands for Root Mean Square, gives you information about the average level over time and Peak gives you an instantaneous read on the loudest peaks for any given moment. In general, RMS metering can tell you more about the true loudness of your audio, so I use it to check general dialog range and when normal spoken dialog is reading somewhere in the -20 average range RMS, it's usually a good spot to start. Now I'm going to playback a piece of this sequence so we can see where it's landing on both the Peak and the RMS level.

(Background noise, car engines, crowd) You'll see the Peak meter is the green meter that's a little higher and the RMS is the blue. (Cars revving their engines) So remember that your ears are really the best reference and as long as you have calibrated your monitors like we spoke about here to output to the correct SPL level, that's really the point of calibration. You can rely on then your ears and not meters. But you can use a meter just as a general ballpark reference.

Once you have completed this kind of calibration and you work with it for a while you'll learn to better trust your ears and they will tell you where the overall levels of your mix are at. So if it sounds too loud to you it is too loud; if it sounds too quiet it is too quiet. It will take a bit of time to get acclimated, but if you work consistently in this calibration for all the projects you work on, they will give you an accurate frame of reference and it will make your mixes translate better to the outside world.

Show transcript

This video is part of

Image for Audio for Film and Video with Pro Tools
Audio for Film and Video with Pro Tools

51 video lessons · 9585 viewers

Scott Hirsch
Author

 
Expand all | Collapse all
  1. 6m 13s
    1. Welcome
      1m 3s
    2. Using the exercise files
      40s
    3. Using this course with Pro Tools 10
      1m 57s
    4. Relinking audio files
      2m 33s
  2. 18m 37s
    1. Understanding the new audio for video features in Pro Tools 9
      5m 17s
    2. Exploring the hardware requirements for Pro Tools 9
      5m 19s
    3. Understanding the audio components of a finished video
      5m 22s
    4. Understanding the audio production workflow
      2m 39s
  3. 25m 10s
    1. Understanding video formats, SMPTE timecode rates, NTSC, and PAL
      6m 21s
    2. Understanding video formats, codecs, and pull-up/pull-down
      5m 16s
    3. Setting up your Pro Tools session for video
      8m 44s
    4. Exporting OMF and AAF files
      4m 49s
  4. 32m 14s
    1. Importing OMF and AAF files
      8m 8s
    2. Importing and the DigiBase browser
      4m 0s
    3. Conforming the OMF import to your template
      6m 51s
    4. Setting up groups and windows
      6m 2s
    5. Spotting film and using markers
      7m 13s
  5. 52m 55s
    1. Organizing the dialog tracks
      5m 0s
    2. Optimizing the dialog in the first pass
      4m 30s
    3. Using room tone
      4m 10s
    4. Creating fades to smooth out audio edits
      5m 4s
    5. Understanding sound effects, ambiences, and backgrounds
      7m 12s
    6. Sweetening and hard effects
      6m 52s
    7. Processing tips for sound effects
      8m 46s
    8. Bringing emotion to the mix with music tracks
      5m 33s
    9. Leveraging clip-based gain in Pro Tools 10
      2m 51s
    10. Exploring AudioSuite enhancements in Pro Tools 10
      2m 57s
  6. 15m 29s
    1. Preparing the session for foley and ADR recording
      9m 19s
    2. Recording ADR and editing with VocALign LE
      6m 10s
  7. 45m 5s
    1. Noise-reducing hums, rumbles, and buzzes
      8m 11s
    2. Eliminating crackles and digital clicks
      5m 30s
    3. Taming plosives and sibilance
      6m 10s
    4. Reducing broadband noise
      9m 26s
    5. Conforming to video changes
      8m 36s
    6. Pitch shifting for effect or utility, TC expansion
      7m 12s
  8. 56m 19s
    1. Setting up for stereo mixing
      5m 11s
    2. Calibrating levels using an SPL meter
      7m 2s
    3. Mixing with automation
      11m 4s
    4. Advanced mix automation
      8m 0s
    5. Automating plug-in parameters
      9m 22s
    6. Mixing with reverb
      7m 20s
    7. Ducking techniques
      8m 20s
  9. 42m 4s
    1. Setting up a surround mix template
      11m 14s
    2. Calibrating for 5.1 surround mixing and bass management
      9m 2s
    3. Mixing and spatial techniques for 5.1 surround
      14m 9s
    4. Downmixing, encoding, and using Neyrinck plug-ins
      3m 38s
    5. Automating techniques for 5.1 surround mixes
      4m 1s
  10. 10m 6s
    1. Print mastering and stem mixes
      5m 47s
    2. Mastering delivery levels and dynamics
      4m 19s
  11. 5m 29s
    1. Backing up your final project
      5m 29s
  12. 18s
    1. Goodbye
      18s

Start learning today

Get unlimited access to all courses for just $25/month.

Become a member
Sometimes @lynda teaches me how to use a program and sometimes Lynda.com changes my life forever. @JosefShutter
@lynda lynda.com is an absolute life saver when it comes to learning todays software. Definitely recommend it! #higherlearning @Michael_Caraway
@lynda The best thing online! Your database of courses is great! To the mark and very helpful. Thanks! @ru22more
Got to create something yesterday I never thought I could do. #thanks @lynda @Ngventurella
I really do love @lynda as a learning platform. Never stop learning and developing, it’s probably our greatest gift as a species! @soundslikedavid
@lynda just subscribed to lynda.com all I can say its brilliant join now trust me @ButchSamurai
@lynda is an awesome resource. The membership is priceless if you take advantage of it. @diabetic_techie
One of the best decision I made this year. Buy a 1yr subscription to @lynda @cybercaptive
guys lynda.com (@lynda) is the best. So far I’ve learned Java, principles of OO programming, and now learning about MS project @lucasmitchell
Signed back up to @lynda dot com. I’ve missed it!! Proper geeking out right now! #timetolearn #geek @JayGodbold
Share a link to this course

What are exercise files?

Exercise files are the same files the author uses in the course. Save time by downloading the author's files instead of setting up your own files, and learn by following along with the instructor.

Can I take this course without the exercise files?

Yes! If you decide you would like the exercise files later, you can upgrade to a premium account any time.

Become a member Download sample files See plans and pricing

Please wait... please wait ...
Upgrade to get access to exercise files.

Exercise files video

How to use exercise files.

Learn by watching, listening, and doing, Exercise files are the same files the author uses in the course, so you can download them and follow along Premium memberships include access to all exercise files in the library.


Exercise files

Exercise files video

How to use exercise files.

For additional information on downloading and using exercise files, watch our instructional video or read the instructions in the FAQ .

This course includes free exercise files, so you can practice while you watch the course. To access all the exercise files in our library, become a Premium Member.

Join now Already a member? Log in

Are you sure you want to mark all the videos in this course as unwatched?

This will not affect your course history, your reports, or your certificates of completion for this course.


Mark all as unwatched Cancel

Congratulations

You have completed Audio for Film and Video with Pro Tools.

Return to your organization's learning portal to continue training, or close this page.


OK
Become a member to add this course to a playlist

Join today and get unlimited access to the entire library of video courses—and create as many playlists as you like.

Get started

Already a member ?

Become a member to like this course.

Join today and get unlimited access to the entire library of video courses.

Get started

Already a member?

Exercise files

Learn by watching, listening, and doing! Exercise files are the same files the author uses in the course, so you can download them and follow along. Exercise files are available with all Premium memberships. Learn more

Get started

Already a Premium member?

Exercise files video

How to use exercise files.

Ask a question

Thanks for contacting us.
You’ll hear from our Customer Service team within 24 hours.

Please enter the text shown below:

The classic layout automatically defaults to the latest Flash Player.

To choose a different player, hold the cursor over your name at the top right of any lynda.com page and choose Site preferences from the dropdown menu.

Continue to classic layout Stay on new layout
Exercise files

Access exercise files from a button right under the course name.

Mark videos as unwatched

Remove icons showing you already watched videos if you want to start over.

Control your viewing experience

Make the video wide, narrow, full-screen, or pop the player out of the page into its own window.

Interactive transcripts

Click on text in the transcript to jump to that spot in the video. As the video plays, the relevant spot in the transcript will be highlighted.

Learn more, save more. Upgrade today!

Get our Annual Premium Membership at our best savings yet.

Upgrade to our Annual Premium Membership today and get even more value from your lynda.com subscription:

“In a way, I feel like you are rooting for me. Like you are really invested in my experience, and want me to get as much out of these courses as possible this is the best place to start on your journey to learning new material.”— Nadine H.

Thanks for signing up.

We’ll send you a confirmation email shortly.


Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

Keep up with news, tips, and latest courses with emails from lynda.com.

Sign up and receive emails about lynda.com and our online training library:

Here’s our privacy policy with more details about how we handle your information.

   
submit Lightbox submit clicked
Terms and conditions of use

We've updated our terms and conditions (now called terms of service).Go
Review and accept our updated terms of service.