An Interview With Mastering Engineer David Glasser

David Glasser Airshow Mastering image

David Glasser is the founder and chief engineer of Airshow Mastering in Boulder, Colorado, and Takoma Park, Maryland. With two Grammy awards for his work, he has mastered thousands of records over the course of his 35 years in the business, including those for some 80 Grammy nominees. An expert in catalog restoration, David has worked on culturally significant releases by Smithsonian Folkways Recordings and the Grateful Dead, among many others. Here’s an interview we did for the Mastering Engineer’s Handbook.

Bobby Owsinski: How did you get started in the music business?

David Glasser: I started in college radio; then I worked for a classical music station in Boston that had the contract along with WGBH to record and syndicate the Boston Symphony and Boston Pops. Syndication in those days consisted of high-speed reel-to-reel duplicates that were sent out in the mail to the various stations, which is what I did. After a while I started doing the recordings as well. From there I worked at NPR in Washington, DC for eight years as a staff engineer doing all the news stuff as well as location jazz and classical recordings and post-production.

How did you get into mastering?

I was doing a lot of location recording and jumped on the Sony F1 [the first inexpensive digital recorder], and like a lot of people got blinded to the fact that it didn’t sound that good but was so convenient. You didn’t have to haul tape machines and a rack of Dolbys [noise-reduction units to quiet the tape hiss] to every gig, but you couldn’t edit any of the tapes. 

I got one of the first Sound Tools systems [the precursor to Pro Tools], and I was suddenly able to edit the things, and it grew from there, from doing simple editing to preparing CD masters. All of a sudden, I was in the mastering business. From there, I bought a used 1610 and just started acquiring all the tools for mastering around 1990 or so, which happened to be when a lot of the small boutique labels were just starting to repurpose their catalogs for CD.

What’s your philosophy on mastering, and how did you come to it?

A lot of it was by studying records that other mastering engineers were doing. A lot of it came out of my NPR experience, where pretty much all the work we did was direct to two-track, so we were dealing with making stereo recordings sound good on air, mostly because we didn’t have the budget for anything else. That made me develop the mastering mindset.

How do you approach a project?

I think anybody that’s decent at this can hear what the producer’s going for and where it works when you hear a mix. Your job then is to get it to where you think the producer was headed. After a while that becomes intuitive and almost a little automatic. You know what’s going to work and what won’t. 

How have things changed in mastering?

Most budgets have gotten way smaller, even for independent artists who didn’t have much of a budget in the really good times. More and more people are doing EPs and singles today.

Are you doing separate masters for online distribution?

Usually not. It’s easy enough to check to see what’s going to work. Most people don’t have the budget for two versions, but often I’ll do a CD version and then a less limited version for the downloads. 

At NPR, one of our mentors always said that if you can make it sound good in your studio, then it’s going to sound good on a TV, AM radio, or anything else. I think that’s true, so I don’t really see a reason to do separate versions except for overall level and limiting.

Are you asked to make loud masters?

It depends. Some people want it to sound good but don’t want it to get lost. Other people will compare it to other records, including ones that aren’t very appropriate for comparison, and ask for a louder record. I’ve found out that my version of really loud is not like other people’s idea of loud. I pull my hair out trying to make it sound really good and really loud. That’s a challenge.

What are you using for a workstation?

SoundBlade. I also have Pro Tools and a Sonoma workstation for DSD. I use Pro Tools for surround and video stuff because it just works so well for that. I also use it for capturing at a different sample rate than the source files are at.

Do you have any favorite plugins?

You know, I don’t use that many plugins. I’ve got the Fraunhofer Pro-Codec, which is really more of a useful tool than a plugin. All the processing that I do is with outboard gear.

On the digital side, I’ve got a Z Systems EQ and compressor and a Weiss EQ and compressor, a TC Electronic TC 6000, and a Waves L2 limiter. In analog, I have some of the new Pultecs, a Prism EQ, an API EQ, a Fairman compressor, an SSL compressor, and a Maselec console.

For convertors, we have a choice between Pacific Microsonics or Prisms. For monitors, I’m using Dunlavy SC-Vs for left and right and SC-IVs for the center and surrounds, with Paradigm subs and Ayre amplifiers.

We’ve also got Ampex ATR and Studer 820 tape machines with headblocks for pretty much anything, if we get a project in on tape.

What’s your signal chain like?

I usually go out into the analog domain. With good enough convertors it’s not totally transparent, but it’s a compromise worth making. Usually it’s analog EQ, analog compressor, A/D convertor, and then maybe some digital EQ and a final limiter. It’s pretty basic and standard.

Is your L2 always at the end of the sign chain?

When I use it, yeah, before dithering. Occasionally I’ll use the limiter in the TC 6000. If it’s something that doesn’t need a lot of limiting, then I’ll stick with the Maselec analog limiter. I’ve just started using the Sonnox Oxford Limiter, and I’m pretty impressed. Very occasionally it will be the limiter in the HDCD model 2. I’ve been starting to use one of the LUFS loudness meters, and I’m going hotter than default Apple setting [–16 LUFS] but only by about 3dB LUFS, so it’s around –13 LUFS. Some of the louder mastering jobs done by other engineers come out at about –9 LUFS. 

I see you do a lot of restoration. How did that come about?

That started when I was back in DC. One of our clients was Smithsonian Folkways, who had tons of great old recordings. We bought one of the first Sonic Solutions NoNOISE systems, and we’ve been doing that sort of stuff ever since.

I love doing oddball things like that. We’ve always jumped on esoteric things like SACD. We don’t do SACDs much anymore, but we do get DSD mixes in, so we have the tools for that. We’ve also invested in the Plangent Processes replay electronics for one of our tape machines. The process removes wow and flutter from analog tapes by extracting the bias signal that’s still on the tape and using it as a reference for the software to eliminate all the speed problems. We used it on all the Grateful Dead studio records, and the results are amazing. 

Is your mastering approach different when you’re doing catalog?

Maybe slightly. If it’s a well-known album, then you can’t stray far from what everybody already knows and loves, so you have to check back with the original a lot. If it’s an archival thing that wasn’t widely known, then probably not. The goal then is to just make it sound as good as you can.

You can read more from The Mastering Engineer’s Handbook and my other books on the excerpt section of

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