The Audio Producer's Guide to Loudness

I've been dealing a lot with this topic lately, as I'm working on my second feature-length film mix in as many months. When you're working on mixing levels for a project that's 90 to 100 minutes long, over the course of several days or even weeks, it's easy to lose track of the loudness of the mix over time. Having a properly calibrated listening environment is key, but having tools to help you keep track of your overall loudness levels over time can be a great tool.

Today as you mix audio productions you most likely monitor levels with a peak meter — those two little bars that jump up and down in tandem with the waveform — and you know those meters don’t always line up with what you hear! You look at two very different pieces of tape on the meter (say, your studio-recorded voice against an interviewee on the phone), tweak those two voices until they appear the same on the meter, and your ears tell you they play back at quite different volumes. You might decide to forego the peak meter for the RMS meter, which can provide a small advantage over a peak meter, but they too do not take perception into account. This is a problem that a new audio measurement method, loudness, can help you solve. Finally there’s a way to simplify levels.
— Rob Byers

Using Logic Pro to generate "air"

A while back, I linked to a Designing Sound article by Doug Murray (whom I later would go on to work for on Dawn of the Planet of the Apes!) about using convolution reverb to generate room tone to fill holes in dialog tracks.  At the end of that linked post, I speculated on using Logic Pro's Space Designer plug in, since I didn't (and still don't) own a convolution reverb for ProTools.  Well, I finally had a reason to sit down and try it out, and the results were pretty great.

Using Space Designer to generate endless room tone!

Using Space Designer to generate endless room tone!

I was really pretty happy with the results. The general process:

  • I cut in ProTools, so when I needed a piece of fill, I'd copy-and-paste a clip of room tone onto a new track that I had labeled "FILLSeed", and consolidated it (OPTION+SHIFT+3) into a new file, and named it according to the character, room, and reel, i.e. "FILLSeed_Chris_BR_R1". I called it "FILLSeed" because I didn't want to confuse this short clip of room tone with the synthesized version that will come out of Logic later.
  • Switching over to Logic, clicking on the disclosure triangle next to the IR Sample label in Space Designer brings up a menu for importing a sound file as your new impulse response.
  • Make sure to set the Dry level to "0", which in less confusing terms would be -∞, and setting the "Rev", or wet signal, to "max." Space Designer is also a multi-channel plug-in, so it will always come out as stereo, so I set the Input slider to the mono setting, over on the left side of the window.
  • Turning on the Test Oscillator insert plugin (with white noise, output at around -50 to -60 dB) on my AIR SOURCE track in Logic, white noise starts pouring into Space Designer, which gets convoluted with the impulse response of room tone that I just imported, and sweet magical room tone comes pouring out!
  • Space Designer does have built-in EQ, so if you need to tweak it a little bit with some high or low-pass/shelf, it's really easy to do that right in the plugin window.
  • I set the input of a second track to be the bus output of my SOURCE track, put it in Record Mode, and record a chunk of fill! Drop that new recording into your ProTools session, and cut it in. Huzzah!

So, there you have it. For about 1/5th the cost of Altiverb, you can buy a copy of Logic Pro and have your own capable convolution reverb. And, you get a pretty nice DAW with some great features of its own, to boot! With the improvements to Core Audio in OS X, having two DAWs open at the same time, using the same hardware, is actually possible, making this type of workflow far less painful.


POST SCRIPT (11/09/2015): While this process has been rendered less useful due to features in software like iZotope's RX and the Ambience Match algorithm, this is absolutely still relevant if you a) don't own RX or 2) don't have it available immediately.

Pro Tip: Comb Filtered Audio

I'm not going to name names, but I'll just say that what I'm about to show you is actually destined for a real live actual television show, with actual famous people on said show. However, if you've ever wondered why sound people are special, it's because we do our best to avoid things like this:

This is bad.

This is bad.

This is a spectrogram of a clip of dialog. See all those shadowy spaces that make lots of horizontal lines? That's what audio people call "comb filtering," and it sounds terrible. This is most likely the result of a mic going into a mixer (or camera) and being combined with itself, but the 2nd signal had a slight delay - like a millisecond or less. Headphones, people! Listen to your sound before you hit record!

Not good.

Mac OS 10.10 Yosemite

Just a quick note to say that I've installed OS 10.10 on my laptop (MacBook Pro, Late 2011), and so far my sound tools (ProTools 11, Logic Pro X, QLab 3) are running with minimal problems. No, Avid has not certified ProTools to run on Yosemite yet, but since my studio Mac Pro is running Mavericks with aplomb (and will for some time to come), I was willing to jump in and make the switch to Yosemite on the MBP. I had been running the beta versions of 10.10 for a couple months on a separate partition, so I had a good idea what I was getting into.

Your mileage may vary. As always, if you're currently in a project, wait until it's finished to upgrade. And, back yo self up!

Sonnet Rack Mount for new Mac Pro/Mini

This is pretty brilliant:

[The] new xMac Pro Server is a 4U rack-mountable enclosure that holds a 2013 Mac Pro, includes three standard PCI Express expansion slots that hook up to the Mac Pro’s Thunderbolt ports, and has enough extra room leftover to fit two 5.25-inch rack peripherals (examples include tape drives or SSDs used for backup purposes).
— Ars Technica

The same company also makes a 1U rack mount for a Mac Mini that-

uses the Mini’s Thunderbolt port to add support for up to two external PCI Express expansion cards.
— Ars Technica

Seems to me a great solution if you're looking to upgrade to a new Mac that doesn't come with PCI card slots - video/audio pros come immediately to mind. ProTools HD users with existing PCIe Core/Accel cards wouldn't have to trade in for a Thunderbolt Native interface. Seems like a great idea to me.

See the products on Sonnet's website:


Massey AAX Plugins!

I don't know how I missed this, but Massey has released 64-bit AAX versions of their plug-ins for ProTools 11! Huzzah!  It comes with a fancy new Wizard installer thingy...

Installin' ma plugz

Installin' ma plugz

So far, it looks like the vt3 3-band EQ, ct5 compressor , L2007 limiter, and TapeHead saturator are the only ones to get the AAX treatment so far, with the others listed as "Coming Soon," but if you're a fan of the Massey plug-in suite and a ProTools 11 user, head on over to Massey's site and download the goodness!

ProTools Tip

Hey folks! Back with another ProTools tip for  you - this one I found through the Avid "Knowledge Base".  I was getting an assertion error -

Could not create a new document because Assertion in "/Volumes/Development/123191/ProTools/DFW/MacBuild/../Views/", line 1547.

- when trying to create a new session. Seems like a pretty major error to be getting, right? I thought so, too.  Anyway, a quick Google search for the text of the error yielded nothing, which is normally a bad sign. But, lo and behold, Digi- sorry, old habit - AVID's Knowledge Base to the rescue!  Holding down the N key while launching ProTools will bring up the Playback Engine dialog before ProTools finishes it's startup sequence. Who knew ProTools even had startup keys?!?

Playback Engine dialog, right in front of the ProTools splash screen!

Playback Engine dialog, right in front of the ProTools splash screen!

For whatever reason, this solves the assertion error that happens when ProTools tries to create a new session when it's not in a familiar audio habitat.  This makes sense to me, because I just fired up away from my home studio and my trusty old Presonus interface.  This startup key will come in handy. Ever startup a ProTools session while connected to a network that has an AppleTV connected, and had ProTools freak out on you about sample rates? Well, here's a quick way around that.

Follow up: ProTools & OS 10.9 Mavericks

So, almost a month ago I posted a link to an article noting that Avid had released an update to ProTools that supported Mavericks, but in the release notes it mentioned that co-installation was not supported.

As it turns out, I can confirm that, at least in a limited role, you can keep and use ProTools 10 (10.3.2, to be specific to my case) and use it while having ProTools 11 and OS 10.9 Mavericks installed.

As it turns out, ProTools 11 has a bug about importing AAF/OMF files. The only suggestion offered by Avid is to open the AAF in 10.3, save, and open back up in 11. Of course, you're not supposed to be able to do this in Mavericks, according to Avid. So thanks a lot, Avid.  But, you can get ProTools 10 to function in Mavericks, but be careful, as Your Mileage May Vary.

Carry on.

iPhone 5C/5S and iOS 7 Review from Daring Fireball

This is a fantastic overview of the new hardware and software Apple is unleashing in the coming days, including a great summary of why the move to 64-bit software is about more than just RAM access. Gruber writes:

The iPhone 5S and 5C

What I find remarkable about the 5S’s benchmarks is not that they’re the current top scores in the mobile world, but rather that they’re at the top despite the fact that Apple famously values the ratio of performance-to-power-consumption far more than performance in and of itself.

Apple doesn't do these types of things just because. There is a real, tangible benefit from it, and I'm confident we'll all see that benefit in the coming years and versions of iOS and the software that runs on it. 

I can't wait to get iOS 7 on my iPhone 4, and I can't wait to get my hands on an iPhone 5S.