Tag Archives: Console

Console Questions

A few simple queries can get you going on just about any console.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

Back when I was in school, we were introduced to “The Four Console Questions.” The idea behind the questions was that, if you walked up to a strange mixer, you could get answers to the questions and be able to get work done. Mixing desks come in many varieties, but there aren’t very many truly different ways to build them that make sense. In any case, all the basic concepts have to essentially stay the same. If a console can’t take some number “a” of audio inputs, and route those inputs to some number “o” of outputs, you don’t have a mixing console anyway.

With the growing commonality of digital mix systems, I feel that the essential “console questions” need some expansion and tweaking. As such, here’s my take on the material that was presented to me over a decade and a half (GEEZE!) ago.

1. Do I Know What I Want To Do?

You might say that this isn’t a console question at all, but in truth, it’s THE most important one. If you don’t know what you want to do with the console, then knowing a bunch of information about the console’s operation won’t help you one iota. The unfortunate reality is that many people try to engage in this whole exercise backwards; They don’t know what they want to accomplish, but they figure that learning the mixer’s whys and wherefores will help them figure it out.

Certainly, learning about a new feature that you haven’t had access to previously can lead you to new techniques. However, at a bedrock level, you have to have some preconceived notion of what you want to accomplish with the tool. Do you want to get a vocal into the FOH PA? Do you want to get three electric guitars, a kazoo, and a capybara playing Tibetan singing-bowls into 12 different monitor mixes?

You have to know your application.

2. How Do I Correctly Clock The Console?

For an analog console, the answer to this is always: “No clock is required.”

For a digital rig, though, it’s very important. I just recently befuddled myself for an agonizing minute with why a digital console wasn’t showing any input. Whoops! It was because I had set it to receive external clock from a master console a few weeks before, and hadn’t returned it to internal clocking now that it was on its own.

You need to know how to indicate to the console which clock source and sample rate is appropriate for the current situation.

3. How Do I Choose What Inputs Are Available To The Channels?

This is particularly important with consoles that support both on-board input and remote stageboxes. You will very likely have to pick and choose which of those options is available to an individual channel or group of channels. What you need to discover is how those selections are accomplished.

4. How Do I Connect A Particular Input To A Particular Channel?

You might think this was covered in the previous question, but it wasn’t. Your global input options aren’t the end of the story. Many consoles will let you do per-channel “soft-patching,” which is the connection of a certain available signal to a certain channel without having to change a physical connection. Whether on a remote stagebox or directly at the desk, input 1 may NOT necessarily be appearing on channel 1. You have to find out how those connections are chosen.

5. How Do I Insert Channel Processing?

In some situations, this means a physical insert connection that may be automatically enabled…or not. In other cases, this means the enabling and disabling of per-channel dynamics and/ or EQ, and maybe even other DSP processing available onboard in some way. You will need to know how that takes place, and with all the possible variations that might have to do with your particular application, it is CRITICAL that you know what you want to do.

6. How Do I Route A Channel To An Auxiliary, Mix Bus, Or The Main Bus?

Sometimes, this is dead-simple and “locked in.” You might have four auxiliaries and four submix buses implemented in hardware, such that they can only be auxiliary or mix buses, with the same knobs always pushing the same aux and a routing matrix with pan-based bus selection. On the other hand, you might have a pool of buses that can behave in various ways depending on global configuration, per-channel configuration, or both.

So, you’ll need to figure out what you’ve got, and how to connect a given channel to a given bus so that you get the results you want.

7. How Do I Insert Bus Processing?

This might be just like question 5, or wildly different. You will need to sort out which reality is currently in play.

8. How Do I Connect A Given Signal To A Physical Output?

Just because you have a signal running to a bus, there’s no guarantee that the bus is actually going to transfer signal to any other piece of equipment. Especially in the digital world, there may be another layer of patching to assign signals to either digital or analog outputs. Bus 1 might be on output 7, because six matrices might be connected to the first six outputs. Maybe output 16 is a pre-fader direct out from channel 4.

You’ll have to figure out where all that gets specified.


Obviously, there’s more to being a whiz at any particular console than eight basic questions. However, if you can get a given signal into the desk, through some processing, combined with other signals you want to combine, and then off to the next destination, you can at least make some real noise in the room.


The Unterminated Line

If nothing’s connected and there’s still a lot of noise, you might want to call the repair shop.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

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“I thought we fixed the noise on the drum-brain inputs?” I mused aloud, as one of the channels in question hummed like hymenoptera in flight. I had come in to help with another rehearsal for the band called SALT, and I was perplexed. We had previously chased down a bit of noise that was due to a ground loop; Getting everything connected to a common earthing conductor seemed to have helped.

Yet here we were, channel two stubbornly buzzing away.

Another change to the power distribution scheme didn’t help.

Then, I disconnected the cables from the drum-brain. Suddenly – the noise continued, unchanged. Curious. I pulled the connections at the mixer side. Abruptly, nothing happened. Or rather, the noise continued to happen. Oh, dear.


When chasing unwanted noise, disconnecting things is one of your most powerful tools. As you move along a signal chain, you can break the connection at successive places. When you open the circuit and the noise stops, you know that the supplier of your spurious signal is upstream of the break.

Disconnecting the cable to the mixer input should have resulted in relative silence. An unterminated line, that is, an input that is NOT connected to upstream electronics, should be very quiet in this day and age. If something unexplained is driving a console input hard enough to show up on an input meter, yanking out the patch should yield a big drop in the visible and audible level. When that didn’t happen, logic dictated an uncomfortable reality:

1) The problem was still audible, and sounded the same.

3) The input meter was unchanged, continuing to show electrical activity.

4) Muting the input stopped the noise.

5) The problem was, therefore, post the signal cable and pre the channel mute.

In a digital console, this strongly indicates that something to do with the analog input has suffered some sort of failure. Maybe the jack’s internals weren’t quite up to spec. Maybe a solder joint was just good enough to make it through Quality Control, but then let go after some time passed.

In any case, we didn’t have a problem we could fix directly. Luckily, we had some spare channels at the other end of the input count, so we moved the drum-brain connections there. The result was a pair of inputs that were free of the annoying hum, which was nice.

But if you looked at the meter for channel two, there it still was: A surprisingly large amount of input on an unterminated line.


More Features VS Groundwork

In this case, groundwork won: There wasn’t a compelling reason to lose it.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

The Video

The Summary

If you have significant prep that’s already done for one mixing system, you might want to avoid losing that effort – even if it would be to put a more powerful/ flexible mix rig into play.


Console Envy

When it comes to sound quality, any console capable of doing the show will probably be fine.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

The Video

The Summary

Which console sounds best? The one with the features you need. If an inexpensive mixer has all the necessary features for your shows, spending more doesn’t have much of a point.


Case Study: Creating A Virtual Guitar Rig In An Emergency

Distortion + filtering = something that can pass as a guitar amplifier in an emergency.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

The Video

The Script

Imagine the scene: You’re setting up a band that has exactly one player with an electric guitar. They get to the gig, and suddenly discover a problem: The power supply for their setup has been left at home. Nobody has a spare, because it’s a specialized power supply – and nobody else plays an electric guitar anyway. The musician in question has no way to get a guitar sound without their rig.

At all.

As in, what they have that you can work with is a guitar and a cable. That’s it.

So, what do you do?

Well, in the worst-case scenario, you just find a direct box, run the guitar completely dry, and limp through it all as best you can.

But that’s not your only option. If you’re willing to get a little creative, you can do better than just having everybody grit their teeth and suffer. To get creative, you need to be able to take their guitar rig apart and put it back together again.

Metaphorically, I mean. You can put the screwdriver away.

What I’m getting at is this question: If you break the guitar rig into signal-processing blocks, what does each block do?

When it comes right down to it, a super-simple guitar amp amounts to three things: Some amount of distortion (including no distortion at all), tone controls, and an output filter stack.
The first two parts might make sense, but what’s that third bit?

The output filtering is either an actual loudspeaker, or something that simulates a loudspeaker for a direct feed. If you remove a speaker’s conversion of electricity to sound pressure waves, what’s left over is essentially a non-adjustable equalizer. Take a look at this frequency-response plot for a 12″ guitar speaker by Eminence: It’s basically a 100 Hz to 5 kHz bandpass filter with some extra bumps and dips.

It’s a fair point to note that different guitar amps and amp sims may have these different blocks happening in different orders. Some might forget about the tone-control block entirely. Some might have additional processing available.

Now then.

The first thing to do is to find an active DI, if you can. Active DI boxes have very high input impedances, which (in short) means that just about any guitar pickup will drive that input without a problem.

Next, if you’re as lucky as I am, you have at your disposal a digital console with a guitar-amp simulation effect. The simulator puts all the processing I talked about into a handy package that gets inserted into a channel.

What if you’re not so lucky, though?

The first component is distortion. If you can’t get distortion that’s basically agreeable, you should skip it entirely. If you must generate your own clipping, your best bet is to find some analog device that you can drive hard. Overloading a digital device almost always sounds terrible, unless that digital device is meant to simulate some other type of circuit.
For instance, if you can dig up an analog mini-mixer, you can drive the snot out of both the input and output sides to get a good bit of crunch. (You can also use far less gain on either or both ends, if you prefer.)

Of course, the result of that sounds pretty terrible. The distortion products are unfiltered, so there’s a huge amount of information up in the high reaches of the audible spectrum. To fix that, let’s put some guitar-speaker-esque filtering across the whole business. A high and low-pass filter, plus a parametric boost in the high mids will help us recreate what a 12″ driver might do.
Now that we’ve done that, we can add another parametric filter to act as our tone control.

And there we go! It may not be the greatest guitar sound ever created, but this is an emergency and it’s better than nothing.

There is one more wrinkle, though, and that’s monitoring. Under normal circumstances, our personal monitoring network gets its signals just after each channel’s head amp. Usually that’s great, because nothing I do with a channel that’s post the mic pre ends up directly affecting the monitors. In this case, however, it was important for me to switch the “monitor pick point” on the guitar channel to a spot that was post all my channel processing – but still pre-fader.

In your case, this may not be a problem at all.

But what if it is, and you don’t have very much flexibility in picking where your monitor sends come from?

If you’re in a real bind, you could switch the monitor send on the guitar channel to be post-fader. Set the fader at a point you can live with, and then assign the channel output to an otherwise unused subgroup. Put the subgroup through the main mix, and use the subgroup fader as your main-mix level control for the guitar. You’ll still be able to tweak the level of the guitar in the mix, but the monitor mixes won’t be directly affected if you do.


What A Mixing Console Isn’t

Magically turning a band into something else isn’t what we’re here to do.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

I’m working on a new video, but it’s taking a while due to scheduling issues. (Being busy isn’t a bad thing, but still…) I figured I should put something up here to prove that I haven’t forgotten this site in the meantime.

So, in regards to a picture of a sophisticated mixing console: The device depicted is not a tool for fixing arrangement problems or interpersonal conflicts.

There, that should stir the pot a little. 🙂


Why Are Faders Labeled Like That?

Gain multipliers are hard to read.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

Want to use this image for something else? Great! Click it for the link to a high-res or resolution-independent version.

I’ve done a lot of typing on this site, and I’m worried that it’s getting stale – so, how about some video?


Don’t Worry About How It Sounds, Worry About What It Does

Any mixer you buy will sound fine. Pick based on the features and how they work.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

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If a console sounds bad – I mean, legitimately and unmistakably – it’s either broken or you’re using it poorly.

(If this post doesn’t kick the hornet’s nest, I will be very surprised.)

My point in this really isn’t to offend. It really isn’t to pick a fight. It really is to be very direct about what to spend your time and worry on when picking out a device to route and combine inputs.

I am by no means the most “well traveled” console operator on Earth. There are guys and girls who have had their paws on many, many more desks than I have, in several thousand more rooms than I’ve been in. At the same time, I have been around long enough to have gotten a pretty good sampling of what’s out there.

I’ve run signals through five-input mini-mixers.

I’ve done “coffeehouse” gigs on ancient monstrosities that I could barely lift. Hugely overgrown beasties which consisted of something like 12 channels, a heavy-as-a-bowel-movement class-AB poweramp (that probably managed a peak output of 400 watts/ side into 8 ohms), knobs and faders that someone with giant hands would have found comfortable, and which had “Peavey” silk-screened on the top surface.

I’ve pushed live audio through consoles that people would be embarrassed to own, and consoles that people would happily show off to some folks, and also through contraptions that nobody could possess but me – because I assembled the thing.

I’ve been on what Avid/ Digidesign would consider a flagship live-mix platform.

I’ve had the opportunity to do real, serious, hands-on, studio-environment stuff with large-frame analog units that would run you about $1,000,000 (in late 1990s dollars) when new.

Let me tell ya, folks,

They all sound basically the same.

Really.

Much like preamps, I have never been in a situation where I thought, “If I just had this one particular console, this would all sound better.” Never.

The Subjective Factor

Some of this has to do with how I work. There are sound craftspersons out there who are into the idea of “special mojo.” The magic of a certain preamp circuit. The plug-and-sweeten behavior of a very specific EQ design. The way the summing bus in a certain piece of signal-combining gear does this beautiful “something” when you hit it just right.

This is all neat stuff. When you’re sitting there, and you’re sure it’s happening, and it’s making your day, that’s great.

It doesn’t generally fit my reality, though. In my world, the time required to find the spot where the snare drum smooshes seductively into the harmonic distortion characteristics of a mic pre is time that would be better spent getting the vocals loud in monitor land. By my methodology, finding a console that gives you some extra forgiveness – or even sounds super-special – when you’re just tickling the overload lights is not a problem to solve. The problem to solve is why your gain structure is messed-up enough to have you bumping into the electrical limits of the desk.

On the flipside, you might be really into this kind of thing, which is fine if it’s working for you and the people around you.

The reason, though, that I point out that I don’t personally find it helpful is for the new folks. The guys and girls who are trying to buy things, and agonizing over spec sheets, scared to death that they’re not going to get enough bang for their buck. The bang is not in those tiny numbers.

What You’re Looking For

What my experience has overwhelmingly shown me over the past years is this: Any console which is basically capable of filling the needs of a given sound-reinforcement scenario will, at a fundamental level, have very comparable “audio circuit” performance to anything else capable of handling that scenario. Modern manufacturing of gear is such that pretty much anything, when run sanely and not engaging in transduction, will have low noise, imperceptible distortion, and transfer response that’s linear from direct-current to dog-whistles.

In other words, there’s no point in looking at SNR, distortion, and frequency response numbers on a mixer’s spec sheet, because it’s all going to be great.

It might not be magic, but it will pass signal in a straight line as long as a component hasn’t failed, and you aren’t hard-clipping the poor thing.

So forget about finding the unit with the best numbers.

Instead, get your mitts on the control surface (whether real or virtual), and figure out if you like how the thing behaves as a tool for intense, realtime munging of loud noises. Does the soft-patching make sense to a rational human? How about to an irrational human on the verge of panic, because something went wrong and the show is 30 seconds from downbeat? Can you make your common routing needs happen without getting lost? If you have preferred EQ setups that you like to use, can you dial them up without struggling? Is it easy to make any built-in compressors and gates act in a way that makes sense? If there are onboard FX engines, can you get the basic delay and reverb sounds you prefer?

These functional considerations are orders of magnitude more important than any subjective sound-quality difference you encounter, especially because they directly affect the “macro-level,” subtle-as-a-kick-in-the-face sound-quality that comes from really messing with an input. At least consider believing me when I say that you don’t actually care about whether or not one console seems to have “slightly deeper and more 3D” bass than another. First, it probably doesn’t – you’re probably just running the “better” console a little louder, or you moved a bit after patching your reference material into the different unit. Second, the tiny little worries evaporate in an instant when the real problem is a musician who “can’t hear the other guitar at all, dude.”

A miniscule difference in distortion characteristics won’t mean squat when the band is 110 dBC continuous in the back of the room without any help from the PA. A 2 dB better noisefloor isn’t worth arguing about when the space is filled with 100 people who are all shouting over each other.

Now…if you’ve got all the basics down, and you’ve found a few different desks that you enjoy using, you’re now ready to nitpick tiny, sonic details. If you’re into that, and you’ve got the time, and the money is all figured out, have at it! If you get a kick out of finding the special mojo, don’t let anyone stop you.

All I’m saying is that the “big mojo” of how comfortable you are with the console as an “audio wrench” matters a lot more. That’s what’s really and immediately going to precipitate what musicians and audio members are going to notice. As is so often true in this business, the ordering of your priorities list is critical.


The Behringer X18

Huge value, especially if you already have a tablet or laptop handy.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

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From where I’m standing, the X18 is proof that Behringer should stop fooling around and make a rackmountable X32 with full I/O. Seriously – forget about all the cut-down versions of the main product. Forget about needing an extra stagebox for full input on the rackable units. Just package up a complete complement of 32X16 analog, put a DSP brain inside it, and sell the heck out of it.

I say this because the X18 is a killer piece of equipment. It packages a whole ton of functionality into a small space, and has only minor quirks. If someone without a lot of money came to me and asked what to use as the core of a small-but-mighty SR rig, the XAir X18 would be high on my list of recommendations.

Software Breaks The Barriers

We’ve hit a point in technology where I don’t see any economic reason for small-format analog mixers to exist. I certainly see functionality reasons, because not everybody is ready to dive into the way that surfaceless consoles work, but any monetary argument simply fails to add up. With an X18, $500 (plus a laptop or tablet that you probably already have) gets you some real big-boy features. To wit:

Channel-per-channel dynamics.

Four-band, fully parametric EQ on all inputs and outputs, plus an additional hi-pass filter that sweeps up to 400 Hz.

Up to six monitor mixes from the auxiliaries, each send configurable as pre or post (plus some extra “pick off point” options).

Four stereo FX slots, which can be used with either send-model or insert-model routing as you prefer.

Sixteen, full-blown XLR inputs with individually(!) switchable phantom.

A built-in, honest-to-goodness, bidirectional, multitrack USB interface.

Full console recall with snapshots.

Mute groups (which I find really handy), and DCA groups (which other people probably find handy).

A built-in wireless access point to talk to your interface device.

Folks, nothing in the analog world even comes close to this kind of feature set at this price point. Buying an analog mixer as a backup might be a smart idea. Starting with an analog mixer because all this capability is overwhelming is also (possibly) a good idea. Buying an analog mixer because it’s cheaper, though, is no longer on the table. Now that everything’s software, the console’s frame-size and material cost no longer dictates a restricted feature set.

I’ll also say that I’ve used X32 Edit, which is the remote control software for Behringer’s flagship consoles. I actually like the XAir software slightly better. As I see it, X32 Edit has to closely emulate the control surface of the mixer, which means that it sometimes compromises on what it could do as a virtual surface. The XAir application, on the other hand, doesn’t have any physical surface that it has to mirror, and so it’s somewhat freer to be a “pure form” software controller.

Anyway, if you really want to dive into mixing, and really want to be able to respond to a band’s needs to a high degree, you might as well start with an X18 or something similar.

Ultranet

I didn’t list Ultranet with the other features above, because it exists outside the normal “mixing functionality” feature stack. It’s also not something you can make work in a meaningful way without some significant additional investment. At the same time, Ultranet integration was what really made the X18 perfect for my specific application.

We wanted to get the band (in this case, a worship band for church) on in-ears. In-ears can be something of a convoluted, difficult proposition. Because of the isolation that’s possible with decent earbuds, getting everybody a workable mix can be more involved than what happens with wedges; Along with assuring that monitor bleed can’t hurt you, you also get the side effect that it doesn’t help you either. Further, you still have to run all your auxiliaries back to the IEM inputs, and then – if you’re running wired – you have to get cables out to each set of ears. The whole thing can get tangled and difficult in a big hurry.

The Ultranet support on the X18 can basically fix all that – if you’ve got some extra money.

Paired up with a P16-D distribution module that links to Ultranet-enabled P16-M personal mixers, each musician can get the 16 main input channels delivered directly to their individualized (and immediate) control. If a player needs something in their head, they just select a channel and crank the volume. Nobody else but that musician is affected. There’s no need to get my attention, unless something’s gone wrong. Connections are made with relatively cheap, shielded, Cat6 cables, and the distribution module allows both signal and power to run on those cables.

The “shielded” bit is important, by the way. Lots of extra-cheap Ethernet cables are unshielded, but this is a high-performance data application. The manufacturer’s spec calls for shielded cable, so spend just a few bucks more and get what’s recommended.

Depending on your needs, Ultranet can be a real chunk of practical magic – and it’s already built into the console.

The Quirk

One design choice that’s becoming quite common with digital desks is that of the “user configured” bus. Back in the days of physical components, never did the paths of “mix” and “auxiliary” buses meet, unless you physically patched one into another somehow. Mix buses, also called subgroups, would be accessed via a routing matrix and your channel panner. Aux buses, on the other hand, would live someplace very different: The channel sends section.

In these modern times, it’s becoming quite common for buses to do multi-duty. From a certain standpoint, this makes plenty of sense. Any bus is just a common signal line, and the real difference between a sub-group bus and an aux bus comes down to how the signal gets into the line. When it comes right down to it, the traditional mix sub-group is just a post-fader send where the send gain is always “unity.”

Even, so, may of us (myself included) are not used to having these concepts abstracted in such a way. In my case, I was used to one of two situations: Dedicated buses existing in fixed numbers and having a singular purpose, or to an effectively unlimited number of sends that could be freely configured – but that always behaved like an aux send.

In the case of the X18, the “quirk” is how neither of those two situations is the chosen path. X18 buses exist in fixed numbers, but are not necessarily dedicated and don’t always behave like an aux send. When a bus is configured to behave as a sub-group for certain channels, it is still called a send and located where the other sends are found. However, its send gain is replaced with an “on” button that either allows post-fader, unity-gain signal to flow, or no signal to flow at all. Now that I’m used to this idea, the whole thing makes perfect sense. However, it took me a few minutes to wrap my brain around what was going on, so I figured I ought to mention it.

Other than my minor befuddlement, there’s nothing I don’t like about the X18. It’s not quite as capable as an X32, but it’s not a “My First Mixer” either. It’s actually within shouting distance, features wise, of the more expensive Behringer offerings. There’s a lot of firepower wrapped up in a compact package when it comes to this unit, and like I said, one of these would be a great starting point for a band or small venue that wants to take things seriously.


Just What Signal Is It, Anyway?

This business is all about electricity, but the electricity can mean lots of different things.

Please Remember:

The opinions expressed are mine only. These opinions do not necessarily reflect anybody else’s opinions. I do not own, operate, manage, or represent any band, venue, or company that I talk about, unless explicitly noted.

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A fader, an XLR cable, and an Ethernet cable walk into a bar.

None of them could have ducked, because cables and faders can’t walk into a bar anyway. Besides, they don’t play nice with liquids, if we were talking about the other kind of bar.

Look, some jokes just don’t work out, okay?

Every object I mentioned above deals with electricity. In the world of audio it’s pretty much all about electricity, or the sound pressure waves that become (or are generated by) electricity. What trips people up, though, is exactly what all those signals actually are. An assumption that’s very, very easy to make is that all electrical connections in the world of audio are carrying audio.

They aren’t.

The Three Categories

In my experience, you can sort electrical signals in the world of audio into three “species:”

  • Audio signals.
  • Data signals that represent audio.
  • Signals that represent control for an audio-processing device.

Knowing which one you actually have, and where you have it, is critical for understanding how any audio system or subsystem functions. (And you have to have an idea of how they function if you’re going to troubleshoot anything. And you’re going to have to troubleshoot something, sometime.)

In a plain-vanilla audio signal, the electrical voltage corresponds directly to a sonic event’s pressure amplitude. Connect that signal – at an appropriate drive level – to a loudspeaker, and you’ll get an approximation of the original noise. Even if the signal is synthesized, and the voltage was generated without an original, acoustical event, it’s still meant to represent a sound.

Data signals that represent audio are a different creature. The voltage on the connection is meant to be interpreted as some form of abstract data stream. That is to say, numbers. The data stream can NOT be directly converted to audio by running it through an electrical-to-sound-pressure transducer. Instead, the data has to reach an endpoint which converts that “abstract” information into an analog signal. At that point, you have electricity which corresponds to pressure amplitude, but not before.

Signals for control are even further removed. The information in such a signal is used to modify the operating parameters of a sound system, and that’s all it’s good for. It is impossible, at any point, for that control signal to be turned into meaningful audio. The control signal might be analog, or it might be digital, but it never was audio, and never will be.

The Console Problem

Lots of us who louderize various noises started on simple, analog consoles. Those mixers are easy to understand in terms of signal species, because everything the controls work on is audio. Every linear or rotary fader is passing electricity that “is” sound.

Then you move to a digital console.

Are those faders passing audio?

No.

Ah! They’re passing data that represents audio!

Nope.

I have never met a digital mixing desk that does either of those things. With a digital console, the faders and knobs are used for passing control data to the software. With an analog console, the complete death of a fader means the channel dies, because audio signal stops flowing. With a digital console, a truly dead fader doesn’t necessarily stop audio from flowing through the console; It does prevent you from controlling that channel’s level…until you can find an alternate control method. There often is one, by the way.

And then there’s the murky middle ground. More full-featured analog consoles can have things like VCAs. Voltage controlled amplifiers make gain changes to an analog audio signal based upon an analog control signal. A dedicated fader for VCA control doesn’t have audio running through it, whereas a VCA controlled signal path certainly does.

And then, there are digital consoles with DCAs (digitally controlled amplifiers), which are sometimes labeled as VCAs to keep the terminology the same, but no audio-path amplifiers are involved at all. Do your homework, folks.

Something’s Coming In On The Wire

I’ve written before about how you can’t be sure about what signal a cable is carrying just by looking at the cable ends. The quick recap is that a given cable might be carrying all manner of audio signals, and you don’t necessarily know anything about the signal until you actually measure it in some way.

There’s also the whole issue of cables that you think are meant for analog, but are carrying digital signals instead. While it’s not “within spec,” you can use regular microphone cable for AES/ EBU digital audio. A half-decent RCA-to-RCA cable will handle S/PDIF just fine.

Let me further add the wrinkle that “data” cables don’t all carry the same data.

For instance, audio humans are interacting more and more with Ethernet connections. It’s truly brilliant to be able to string a single, affordable, lightweight cable where once you needed a big, heavy, expensive, multicore. So, here’s a question: What’s on that Ethernet cable?

It might be digital audio.

It might be control data.

It might even be both.

For instance, I have a digital console that can be run remotely. A great trick is to put the console on stage, and use the physical device as its own stagebox. Then, off a router, I run a network cable out to FOH. There’s no audio data on that network cable at all. Everything to do with actually performing audio-related operations occurs at the console. All that I’m doing with my laptop and trackball is issuing commands over a network.

It is also possible, however, to buy a digital stagebox for the console. With that configuration, the console goes to FOH while attached to a network cable. Because the console has to do the real heavy-lifting in regards to the sound processing, digital audio has to be flying back and forth on that network connection. At the same time, however, the console has to be able to fire control messages to the stagebox, which has digitally remote-managed preamp gain.

You have to know what you’ve got. If you’re going to successfully deploy and debug an audio system, you have to know what kind of signal you have, and where you have it. It might seem a little convoluted at first, but it all starts to make logical sense if you stop to think about it. The key is to stop and think about it.