Digital vs. Analog – Mixing

Digital vs. Analog – Mixing
When it comes to mixing, the debate gets more interesting. There are basically three camps: The “in the box” all digital people, the all analog “big consoles supported by racks and racks of additional analog gear” -people, and the hybrids (that do a little bit of both.) Before I tell you which camp I belong in, let me talk a little bit more about why people prefer these three ways.

Big Analog Consoles
A good example from the Big Analog Consoles camp is the very successful and well known New York Mix Engineer Michael Brauer. Projects arrive to him in both analog and digital form. If it’s analog tape, he has a player and can mix directly from that (although it will be synced up to Protools so that he can transfer individual tracks there for editing if needed). If it’s digital tape or any DAW’s project files, he (or more likely his assistant) will transfer it all to Protools first.

Michael uses an 80 input SSL J Series Console together with racks, racks, and even more racks of great (and very expensive) analog outboard gear. (Take a look at the soundtowers section of his website.) All the tracks are output individually from Protools to the SSL via the standard Digidesign DA-Converters. Once analog on the SSL, everything gets sent to all of Michael’s toys in various complicated way, and then finally brought back to a digital stereo track again.

From a technical purist point of view, that means that everything in the mix ultimately has gone through an extra stage of conversion (analog source to digital recording, digital playback to analog console, then analog console output to digital recording) compared to mixing in the box. Out of all the things that affect the sound of the final product, I’d say it’s one of the least significant ones, but it’s definitely at least as valid as the issue of sample rate or arithmetic used (24, 32, 48 or 64 bit, fixed or floating point etc.) when mixing in the box.

The main benefits of mixing this way (at least for Michael) are that:

  • It works really well. Countless hit records have been mixed this way by the top mixing engineers in the industry.
  • The gear he uses is the best of the best, acquired over many years. He picked every piece because he tried it and liked it. In a way, it represents one aspect of his accumulated knowledge gained from years and years of work.
  • Clients get very impressed, and gear junkies have multiple orgasms when they attend one of his sessions.

The main drawbacks compared to an all digital scenario are:

  • Equipment Cost. All his gear has taken years to collect and I really have no idea how much his collection is worth. Needless to say, an engineer that’s just starting out will not be able to have 24 hour access to such an array of equipment (unless he happens to land the assistant position for Michael or one of the other top mix engineers that work this way).
  • Maintenance. Keeping all that outboard gear, as well as the console, in good shape requires a skilled technician. That’s why engineers at this level usually have permanent residence in a major commercial studio with in-house technicians and studio managers.
  • Recallability. I know Michael has a nice system down for recalling every mix session, including the automation on the console, all the physical routing done in the patch bays, as well as detailed notes of the settings for all of the outboard gear used in the session, but the time it takes for the assistant to setup a session is still significantly more than the few seconds it takes to load up a session in Logic or Protools.
  • Cost. This is the biggest one. Housing all that gear, keeping it maintained, having a studio staff and an assistant all cost money, and naturally, that cost gets passed on to clients.

In The Box Mixing
In the box Mixing means that the mixing, or summing, of all the individual audio tracks that make up a song is done inside the computer. I would include mixing on an all digital Mixing Console in this camp as it’s really only a glorified computer with very custom hardware. Sure, the arithmetic used (24 or 48 bit fixed vs. 32 or 64 bit floating point etc, that I referred to before) varies, but that’s true of different DAW software too.

Since this style of working became practically possible sometime around 1995, (depending on your definition of practical) many people have expressed concerns about it and made statements about the negative impact it supposedly has on the quality of the final product. Naturally, the validity of these concerns and the accuracy of the negative statements varied widely.

  • The bit rates used for audio transport and summing (arithmetic) are too low.
  • Digital summing just doesn’t sound the way analog summing does.
  • Plugin versions of classic outboard gear do not sound like the original units.
  • The delay that inevitable happens on tracks after inserting plugins destroy the phase coherency of the recording.
  • Multi-bus mixing techniques cannot be used inside a DAW without loss of phase coherency due to plugin latency.
  • The available audio headroom on the master track is not as great as it is on good analog consoles.

I’m sure there are more, but let me go through these one by one:

  • The bit rates certainly were a bit low in the beginning, and it could arguably have lead to lesser quality in the final products. Today, however, all DAW’s use at least 32 bit floating point arithmetic which, so long as the software is used correctly by engineers who know what they are doing, should not present a problem. Some of the DAW’s even use 64 bit float or 48 bit fixed which makes it hard even for incompetent people to run into headroom problems.
  • The issue of the sound of digital vs. analog summing is very strange to me. First of all, different analog boards can sound very different from each other. In any analog design, the sound is highly dependent on what kind and the quality of all the components used. And none of them will sum signals perfectly. Whichever analog mixing board one prefers is totally a matter of taste, and for many people, their choices (if given choices) might vary depending on what (song, genre, how it was recorded etc) they are about to mix. So, to lump all analog mixing together and contrast it with digital mixing just doesn’t make much sense to me.

    Inside a DAW, the summing really is perfect in the theoretical sense of the word. Not to say that every mixer will prefer the sound of it, but the summing in all the major DAW’s will sound very close to, if not completely, identical, and to choose to compare this one sound to the wildly varying sound of analog would be kind of like picking one fruit, say a pineapple, and then compare that alone with all other fruits as a group. Everyone is of course entitled to their own taste in what equipment they like to use when they mix, but to categorically say that analog summing sounds better than digital summing is just plain stupid.

    Here’s a good quote from the very successful mix engineer Dave Pensado: Show me a guy who doesn’t like a particular format, and I’ll show you a guy who doesn’t know how to use it.

  • When it comes to plugin emulations of classic gear not sounding like the originals, I don’t doubt it. This is very different than comparing what is best. It’s extremely hard to make a faithful emulation, and I don’t think they will ever be perfect. On the other hand, why does it matter whether the emulations are perfect or not? Maybe for someone who used a particular piece of equipment for every single song, then lost it, and is now trying to replace it with a plugin. He’s actually after a clone of what he lost. Most mixers, however, are not after clones. They are simply trying to mix music, and will try whatever they happen to try. If it sounds good, they’ll use it, and if not, move on to something else. I would say that often, individual units of the same analog piece of gear might sound more different from each other than from a plugin emulation (compare two different vintage 1176 compressors that might have been manufactured at different times, with slightly different components, and have been treated with very varying care over the years to the sound of UA’s 1176 plugin processor, and you probably have three different sounds, and faced with a blind-test, I’m sure most engineers wouldn’t be able to tell which was which unless they happened to be the actual owners of those two units.
  • The delay, or latency, that comes from inserting plugins has definitely been an issue, and if not dealt with correctly, it often did cause phase coherency problems. It was always possible (even though inconvenient) to deal with this through manually keeping track and compensating for latency though. And today, all the major DAW’s feature automatic latency compensation. The one omission here is the LE version of Protools which is one of the reasons that I wouldn’t recommend it for serious mixing.
  • Multi-bus mixing techniques work great in any DAW that feature full automatic latency compensation.
  • This can be true, depending on which DAW is compared to which specific analog mixing console. Mostly, this is not a problem anymore, any professional Mix Engineer should be able to easily deal with headroom issues regardless.

Now, what about the benefits of in the box mixing?

  • Complete and perfect recall-ability. No need for assistants spending time tweaking knobs while looking at photos of how a unit was set at a session that took place three weeks ago; no strange issues resulting in the patch bay not having been reset exactly as it was the last time the session was open; no need to use a different compressor on the lead vocal this time since the one originally used was sent out for repair, and so on…
  • Use as many copies of the plugins you like as your computer can handle. (and with today’s, computers, that number has gotten really really large) So if you liked the sound of a particular compressor on one of your backup singers, no reason not to try it on the other backup singer too.
  • Plugins don’t take up physical space in your studio. Tons of outboard gear means having to house it all, preferably within reach of you while you work which might lead to acoustic issues in your mixing space (reflections from the flat surfaces of your equipment racks and so on). Outboard gear also means either less space in your room, or having to pay for a larger room. With plugins, all your virtual equipment is right at your fingertips – either through the use of a mouse or through control surfaces of various sizes. Whatever you prefer.
  • Plugins are generally much, much less expensive than equivalent outboard units, which of course means that whatever your budget is, you’ll be able to afford many more plugins and thus have a much larger arsenal of available tools at your disposal when you work.
  • With plugins (used in a DAW) you’ll be able to easily save complete channels strip settings in a library of your own, so that you can easily get that same great sound you had on the vocal in another project, for the current one. Just load it up with EQ’s, Compressors, Delay’s, Reverbs and all. And, as you work, you can of course copy settings from one track to another within your current session.

I could go on here, but a lot of these advantages or obvious and already well known, so I’ll stop.

Hybrid Mixing
The point of the hybrid approach is of course to try and merge the respective benefits of both of the above while leaving most of the disadvantages out. Another reason to go hybrid is of course that many engineers already have a lot of analog gear that they would hate to get rid of. At the same time, they see all the advantages of in the box mixing and want to get in on that.

Some hybrid mixers already own a large analog console and have the space and financial means to support it, yet they want the ease of use that come with working in the box. So they might end up with a scenario where they bring all the tracks out of the DAW through individual outputs that end up on the inputs of their consoles, just like the Big Analog Consoles people. However, they’ll still have lots of plugins running on all the tracks inside the DAW, and they’ll use the automation of the DAW while leaving all the faders on their analog console at unity gain. That way, they never have to deal with recalling the analog settings since they always stay the same while all their plugin settings get recalled by the DAW. This approach, however, prevents them from using the EQ’s on their boards, and it might (so long as they don’t want to start documenting everything again) prevent them from using many great multi-bus mixing techniques. So in essence, they really only use their mixing consoles for the summing. If one happens to really like the way a particular console sums audio, then that’s a good reason to have a setup like this.

This scenario also leaves the option of plugging in an old favorite on a track. Just connect that Pultec EQ to the insert of the channel where you usually have the lead vocal. And the time spent having to document the settings used is quite minimal since it’s just for one track.

A newer spin on this strategy which keeps its benefits while making the whole setup smaller and more transparent, is the use of a so called summing box. Various companies basically make compact mixing consoles that don’t have any faders or knobs (and thus doesn’t need any hands on attention) yet they still feature the summing and routing capabilities of an analog console, allowing select pieces of gear to be patched in before the summing like I described above.

I would say this last approach is the only analog approach that makes sense for a beginner that doesn’t already have a significant investment in analog gear or has a knowledge investment or an emotional attachment to analog gear. What it really comes down to is of course whether one prefers the sound of a particular summing box over the sound of digital summing, and how much money and complexity that preference is worth.

If it’s mostly about getting to use a few treasured analog pieces while mixing, there is a simpler way to do so while staying in the box. So long as your computer audio hardware has additional unused audio in and outputs, it’s easy to insert an analog piece of gear into a digital channel strip. Most DAW software feature insert plugins that enables compensation for the latency that occurs during the roundtrip through the DA converter, to the analog piece of gear, and back to the DAW through the AD converter.

So, what do I do?
Well, as you might have already guessed, I mix in the box. It’s simply what makes the most sense for me. Occasionally, I’ll patch the compressor section of my Rupert Neve Portico Channel Strip into a vocal track inside a Logic session. My studio is setup so that it’s easy to do that, but even so, it doesn’t happen very often. Logic’s compressor plugin, with the different sensor technology emulations, sounds really good to me, so I’m pretty much covered.

Even while recording, I don’t use the compressor part of the Portico unit to get a particular sound, but rather, just to level the signal a bit in a clean and transparent way without affecting the sound, so that I can record at a hotter level and thus achieve better audio resolution through my converters.