Category Archives: Live Audio Tactics

Tips, tricks, and strategies for concert sound in small venues.

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.


It’s Gonna Take A Minute

The secret to better shows is practice. Practice requires time.

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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The Video

The Summary

We should strive to do our best work. The best work possible on the first try is usually not as good as the best work possible on subsequent tries – and we need to be okay with that.


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.


The Power Of The Solo Bus

It’s very handy to be able to pick part of a signal path and route that sound directly to your head.

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.

headphonesWant 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

Need to figure out which channel is making that weird noise in the midst of the chaos of a show? Wondering whether your drum mics have been switched around? Wish you could directly hear the signal running to the monitor mix that’s giving people fits? Your solo bus is here to save the day!


Case Study: FX When FOH Is Also Monitor World

Two reverbs can help you square certain circles.

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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The Video

The Script

Let’s say that a band has a new mixing console – one of those “digital rigs in a box” that have come on the scene. The musicians call you in because they need some help getting their monitors dialed up. At some point, the players ask for effects in the monitors: The vocals are too dry, and some reverb would be nice.

So, you crank up an FX send with a reverb inserted on the appropriate bus – and nothing happens.

You then remember that this is meant to be a basic setup, with one console handling both FOH and monitors. Your inputs from the band use pre-fader sends for monitor world, but post-fader sends for FX. Since you weren’t building a mix for FOH, all your faders were all the way down. You don’t know where they would be for a real FOH mix, anyway. If the faders are down, a post-fader send can’t get any signal to an FX bus.

Now, you typically don’t want the monitors to track every level tweak made for FOH, but you DO want the FX sends to be dependent on fader position – otherwise, the “wet-to-dry” ratio would change with every fader adjustment.

So, what do you do?

You can square the circle if you can change the pre/ post send configuration to the FX buses, AND if you can also have two reverbs.

Reverb One becomes the monitor reverb. The sends to that reverb are configured to be pre-fader, so that you don’t have to guess at a fader level. The sends from the reverb return channel should also be pre-fader, so that the monitor reverb doesn’t end up in the main mix.

Reverb Two is then setup to be the FOH reverb. The sends to this reverb from the channels are configured as post-fader. Reverb Two, unlike Reberb One, should have output that’s dependent on the channel fader position. Reverb Two is, of course, kept out of the monitor mixes.

With a setup like this, you don’t need to know the FOH mix in advance in order to dial up FX in the monitors. There is the small downside of having to chew up two FX processors, but that’s not a huge problem if it means getting the players what they need for the best performance.


The Difference Between The Record And The Show

Why is it that the live mix and the album mix end up being done differently?

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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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Jason Knoell runs H2Audio in Utah, and he recently sent me a question that essentially boils down to this: If you have a band with some recordings, you can play those recordings over the same PA in the same room as the upcoming show. Why is it that the live mix of that band, in that room, with that PA might not come together in the same way as the recording? The recording that you just played over the rig? Why would you NOT end up having the same relationship between the drums and guitars, or the guitars and the vocals, or [insert another sonic relationship here].

This is one of those questions where trying to address every tiny little detail isn’t practical. I will, however, try to get into the major factors I can readily identify. Please note that I’m ignoring room acoustics, as those are a common factor between a recording and a live performance being played into the same space.

Magnitude

It’s very likely that the recording you just pumped out over FOH (Front Of House) had a very large amount of separation between the various sources. Sure, the band might have recorded the songs in such a way as to all be together in one room, but even then, the “bleed” factor is very likely to be much smaller than what you get in a live environment. For instance, a band that’s in a single-room recording environment can be set up with gobos (go-betweens) screening the amps and drums. The players can also be physically arranged so that any particular mic has everything else approaching the element from off-axis.

They also probably recorded using headphones for monitors, and overdubbed the “keeper” vocals. They may also have gone for extreme separation and overdubbed EVERYTHING after putting down some basics.

Contrast this with a typical stage, where we’re blasting away with wedge loudspeakers, we have no gobos to speak of, and all the backline is pointed at the sensitive angles of the vocal mics. Effectively, everything is getting into everything else. Even if we oversimplify and look only at the relative magnitudes between sounds, it’s possible to recognize that there’s a much smaller degree of source-to-source distinctiveness. The band’s signals have been smashed together, and even if we “get on the gas” with the vocals, we might also be effectively pushing up part of the drumkit, or the guitars.

Time

Along with magnitude, we also have a time problem. With as much bleed as is likely in play, the oh-so-critical transients that help create vocal and musical intelligibility are very, very smeared. We might have a piece of backline, or a vocal, “arriving” at the listener several times over in quick succession. The recording, on the other hand, has far more sharply defined “timing information.” This can very likely lead to a requirement that vocals and lead parts be mixed rather hotter live than they would be otherwise. That is, I’m convinced that a “conservation of factors” situation exists: If we lose separation cues that come from timing, the only way to make up the deficit is through volume separation.

A factor that can make the timing problems even worse is those wedge monitors we’re using, combined with the PA handling reproduction out front. Not only are all the different sources getting into each other at different times, sources being run at high gain are arriving at their own mics several times significantly (until the loop decay becomes large enough to render the arrivals inaudible). This further “blurs” the timing information we’re working with.

Processing Limits

Because live audio happens in a loop that is partially closed, we can be rather more constrained in what we can do to a signal. For instance, it may be that the optimal choice for vocal separation would simply be a +3 dB, one-octave wide filter at 1 kHz. Unfortunately, that may also be the portion of the loop’s bandwidth that is on the verge of spiraling out of control like a jet with a meth-addicted Pomeranian at the controls. So, again, we can’t get exactly the same mix with the same factors. We might have to actually cut 1 kHz and just give the rest of the signal a big push.

Also, the acoustical contribution of the band limits the effectiveness of our processing. On the recording, a certain amount of compression on the snare might be very effective; All we hear is the playback with that exact dynamics solution applied. With everything live in the room, however, we hear two things: The reproduction with compression, and the original, acoustic sound without any compression at all. In every situation where the in-room sound is a significant factor, what we’re really doing is parallel compression/ EQ/ gating/ etc. Even our mutes are parallel – the band doesn’t simply drop into silence if we close all the channels.


Try as we might, live-sound humans can rarely exert the same amount of control over audio reproduction that a studio engineer has. In general, we are far more at the mercy of our environment. It’s very often impractical for us to simply duplicate the album mix and receive the same result (only louder).

But that’s just part of the fun, if you think about it.


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.

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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.


Monitor World – Is “More” Better?

Often, the answer is “nope.”

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.

Monitor world is a PA system, just like FOH is a PA system. The only difference is that monitor world handles a few very small audiences, and FOH usually deals with one comparatively large audience. All the helpful AND problematic physics considerations are the same.

This being the case, the stage is yet another place where simply piling up more and more boxes (all doing the same thing) to get “more” can be counterproductive. A vocalist wants more vocal, but their monitor is already doing everything it can, so you add another box. Does it look impressive? Yes! Is it louder? Yes! Is it better?

Yea- er…well…wait a second…

What you very well might end up with is a different set of issues. If the singer isn’t precisely situated between the wedges, the wedge outputs arrive at different times. This means that all kinds of destructive phase weirdness might be happening, and that can lead to intelligibility issues. The vocal range is very easy to louse up with time-arrival differences, and a sensation of “garble” can lead to a player wanting even MORE monitor level in compensation. In that instance, you haven’t actually gotten anywhere; Monitor world is louder, but it’s not any easier to hear in the information-processing sense. You also have greater effective loop-gain with that extra volume rocketing around, which destabilizes your system.

Plus, the low-frequency information still does combine well, which can lead to a troublesome buildup of mud. This goes double for everybody who’s off-axis (and that’s probably just about everybody who isn’t the intended audience of those wedges). That makes them want their own mixes to be hotter, which compounds all your problems even more.

And, of course, there’s even more bleed into FOH.

The brutal reality is that, for any single sound that a given player needs to hear, that signal will always sound better coming from a single box that “can get loud enough.” More wedges (all producing the same output) can only combine less and less coherently as you add more of them.

“But, Danny,” you protest, “you’ve done dual wedges for people. You’ve even rolled out some really excessive deployments, like the one in the article picture. Who are you to tell folks not to do that kind of thing?”

Fair point! In response:

1) It’s because I’ve tried some strange monitor solutions that I can say they weren’t necessarily improvements over simpler approaches.

2) Sometimes you do things that look cool, accepting that you’ll have to deal with some sonic downsides as a result.

3) Just because you’ve piled up a bunch of wedges, it doesn’t require you to put the exact same thing through each enclosure. Somebody might have two boxes in front of them, but one might be for vocals only and the other for instruments only.

With some bands, especially those who are naturally well balanced and don’t need a ton of monitor gain, the extra fun-factor and volume bump can trade off favorably with the coherence foibles. As the rest of this article indicates, yes, I am in the camp that says that a single box will always “measure better.” However, there’s more to life than just “measuring better.” If you have some room to compromise, you can be a little weird without hurting anything too badly.

Audio is an exercise in compromise. If you know what the compromise factors are, you can make an informed judgement. If you know that throwing a bunch of boxes at a problem might cause you other problems, then you’ve got more knowledge available to help you make the right decision for a fix.


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. 🙂


Baskets, Bees, and Flies

Quality generally beats quantity.

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.

Sometimes, more IS more. It doesn’t matter how nice your mic cables are if you don’t have enough of them. If the show absolutely requires 24 channels, and you have a console with 16 really amazing channels…well, you’re still short by eight.

Yet, there are still plenty of instances where “a handful of bees is better than a basket of flies” (as Moroccans might say).

For instance, some folks are really hung up on the idea that a “main” PA speaker should be built around a 15″-diameter low-frequency driver. The idea is that bigger is better, but that’s not always so. Given a choice, I’ll take a good box built around a 12″ cone over a mediocre offering constructed around a 15. A well-designed 12 can be kinder to the vocals, because the cone driver is better at “playing” higher and covering the range that a small horn-driver can’t quite reach down into. Sure, the 12 probably won’t go as low, but if you want to be “loud” below 100 Hz you’re going to want subwoofers anyway. (For the record, I would never turn my nose up at a perfectly decent box that used a 15 or two.)

Also talking about speakers, there are people who believe a PA with more boxes is superior to a rig with fewer. The problem is that you have to take deployment into account. If you already have the necessary horizontal and vertical coverage happening, more boxes just act to cause more interference problems. The system looks cool because it’s bigger, and it gets louder because there are more boxes, but it doesn’t actually sound better. It might even sound terrible with all that comb-filtering going on. Coverage is sort of like what The Mad Hatter said to Alice: “When you get to the end, stop.”

This applies to bands too, especially when it comes to vocalists. One really brilliant singer with one mic is almost always light-years better than a whole group of vocalists of questionable quality. Beyond the basic aesthetics, not-so-hot singers tend to require a lot more gain to be heard (because they usually haven’t developed much vocal power), and that can easily lead to a system being run on the knife-edge of feedback all night.

…and speaking of people, how about crew-members? Any day of the week, and twice on Sunday, I’ll gladly take one knowledgeable, pleasant, and punctual helper over 15 punters who are late, surly, and have no idea what’s going on.

Tossing more and more junk at a problem rarely fixes the problem. You might eventually smother your issue or manage to distract from it, but the bugbear is still sitting beneath the pile. Applying a sufficient fix, on the other hand, works very reliably. There are times when you need “more.” There’s no getting around that. However, it’s important to avoid using “more” as a substitute for having what will actually do the job effectively.