Check 1, 2...

The next time you're in front of your mixer or console, take a look at all the knobs. You've got the usually bass, mid, treble, and maybe a frequency sweep if you've got parametric EQ on your board. There are probably Aux sends, Effects sends, and the overall channel volume. But one knob I've never seen on a board is a "Sucks" knob. You know, something you can turn down if the sound sucks (or turn up if it's your last night as the band's sound man).

So if the sound coming into the board sucks, there's not a 1-knob solution to fix it, is there? There's only so much you can do with EQ (and extreme EQ moves have their own drawbacks). So what's a sound man on a budget supposed to do?

If you have a crappy sound source or a crappy mic on it, you're pretty much just trying to polish a turd from then on.

Bad sources...sometimes we can do something about that, and sometimes not. If you're trying to mic up a drummer who has a kit that the heads haven't been replaced in this century or doesn't know how to tune them, your hands are tied. Likewise, the guitarist who thinks that a $100 Fender Squire into a Behringer distortion box and a Roland Cube is "his sound" is going to come through like an ice pick to the forehead. But at least you can avoid making it worse than it already is.

And for the musicians that have great gear and know who to use it, so much the better.

A great guitar tone can be ruined by putting a cheap (or damaged) mic in front of it. Likewise, your vocalist could wind up sounding like the speakers at Sonic Drive-In with a $19 no-name mic. No, these days there are a lot of great mics for under $100, and those mics will last you for years if you take care of them.

It's no secret that I'm an old school Shure guy when it comes to mics. In fact, I've done shows with nothing but SM-57's on everything (including the kick drum), and it sounded pretty darned good. An SM-57 will set you back $80, but for the money there's not a better mic in my book for guitar, snare, and toms. Some vocalists like 'em too.

For vocals, the $100 SM-58 (very similar design to the 57) is the industry workhorse. When you see bands on arena shows that could use any mic they wanted still using those for vocals, that's says something. Plus, they're tough as anything....you can darn near pound a nail with 'em and then start singing (note: Please don't try this yourself...I can't be responsible for your mic if you do).

I've also got to give props to Audix for their offerings in vocal mics now...I'm starting to see a lot of them on major shows. In one of my bands, the lead vocalist has started using the OM-7, which was tailor made for a rock-n-roll band with a lot of on stage volume. You get right up on the mic, and it punches right through. But, it's designed so that it doesn't pick up a lot of instrument bleed when you step away from it. It's pricy (about $230 on the street), but if you're a singing guitar player with a loud amp right behind you it's the perfect mic.

I like good ol' dynamic mics on male vocals, but for females I really like to put a condenser on them. One of the best I've heard is the Shure Beta 87C. Great output and a wonderfully open top end. You do have to be a little careful with it...it's got a lot of reach and will pick up the drummer's cymbals very well (which may or may not be a good thing). It's about $250, but if you're a female vocalist and serious about your sound you owe it an audition.

If those prices are a bit much for you, then look at Shure's PG series of mics. They're about half the price and pretty close in quality. Truth be known, the PG-56 has become my new favorite on toms. It's a compact design with a built-in stand adapter. In fact, for about $65 you get the mic and a rim-mount mic holder that attaches to the edge of the drum. For the average drum kit, that's 3 or 4 mic stands that just disappeared from your stage!

If you're wanting to mic the kick drum (and this actually should be the first drum to get attention), then take into account what your PA system will support. If you have a couple of speakers on sticks with 12 inch woofers, you're not going to be able to carry any appreciable amount of low end through them. You could stick a 57 in the kick and pick up a little bit of the beater sound just to help convey the presence of the kick, but that's about all.

But, if you've got some decent full range cabinets and some subwoofers then you've got some options. There are a lot of mics out there now optimized for kick drums. They already have an EQ curve built into them that has a cut between 200 to 400Hz, and a boost up around 3-5kHz.

My favorite kick drum mic is the EV 868, but a lot of people like the Audix D6. The AKG D-112 is a long time standard for mic'ing kick drums as well (I used them back in the 80's). You're looking at around $200 for any of these mics, but they will save you a lot of time at the board trying to dial in a decent sound. The D6 is probably the most aggressive sounding, followed by the 868, with the D-112 being the most mellow of the bunch.

Most sound guys don't worry about overhead mics on a drum kit except on a big stage, but they're missing a lot. A couple of condenser mics up over a drum kit add a lot of space and air to the sound...it really opens it up. In fact, in smaller rooms I'll bring the overheads up first on the board, and then use individual mics on the drums to fill in.

Again, you could spend hundreds (or even thousands) on those mics, but for club and regional work I've found some really good, inexpensive options. I know I rag on Behringer a lot (but hey, most of their rack mount gear that I've bought has crapped out on me). But one thing they got right was the C-2 condenser mic. It's an omni directional with a nice flat response. And get this, you can get a pair of them for about $60.

I know that this post read like a Shure and Audix commercial, but I'm not making any money from 'em. This is just the gear that I've had experience with and has had a good track record with me.

And oh yeah..last week's trivia question....

Q: What's the best song to end your sound check with?
A: The first song of the night!

Think about it, whatever tweaks you make to that tune means that you're starting from much more of a "known" point. Of course, if you're running late and have to sound check in front of an audience this doesn't work. In that case you want to check with a "dense" song....lots of vocals and heavy instrumentation....unless you're an acoustic band:)

Next week, let's get our hands on a console and get the monitors for the band set up.

Until then, keep the meters out of the red!


Ken

Ken Carver has been a musician and performer since the early 70's, and involved with live music production since the mid 70's. He worked for 15 years as a broadcast engineer, building numerous studios and transmitter sites around Texas. He's also worked in Critical Care Communications for the medical industry, R&D for an automated lighting manufacturer, and owned Project Lighting & Sound in the 80's. He currently heads up an R&D Hardware Technician Team at National Instruments in Austin, and still performs on the weekends in the Central Texas area. You can reach Ken at itsjustlogistics@gmail.com

Ready, Fire, Aim!

So, we're at the point where we've arrived at the venue, loaded in the show, and got everything hooked up.  It's time to fire up the sound system and see if our preparations have paid off.  If you've got good power, checked all of your cables, and didn't break anything on the way to the gig you should have something that resembles audio oozing out of your speakers now.

What happens now depends on just how elaborate your sound system is.  If you're simply putting vocals through the PA, it's going to be quick and easy.  However, if you're mic'ing up an entire band, then you've got as much as 16 (or more) channels to adjust and then mix all together (I've done regional bands in large clubs that filled up a 48 channel desk).  So, in the next few weeks we'll be covering setting up this aspect of the show, starting simple and getting more complex.

But before we start building a mix, what can we do to make sure it sounds as good as we can make it?  Well, it might surprise you that the physical placement of mics and speakers can make a huge impact.

First, your main speakers.  This may seem really basic, but a lot of bands miss this.  Make sure your speakers are pointing at the intended audience.  If there's a dance floor or "listening" area in the venue, that's what you want to cover.  You do not want to be blasting the bar area.  If bartenders can't hear, they can't take drink orders.  If they can't take drink orders, they don't make any money.  It goes downhill from there.

Having your speakers pointing straight out from the stage area is frequently what you don't want.  Why?  You know those horns in your main PA speakers?  Yeah, the things that spit out all the treble....they work just like a nozzle on the end of a garden hose.  So your sound doesn't shoot straight out, it's in a spray pattern anywhere from 60 to 90 degrees wide.

So while your speaker may look like it's "aimed" at the audience, you could still be directing a lot of acoustic energy where you don't want it...like the above mentioned bar.  Yeah, I know...it looks cooler to have 'em pointing straight out (and I've had to fight this battle).  But I ask you this...did the audience come to see you perform or stare at your PA?  Yeah, that's what I thought.  Now, you go tease your hair and let me finish my job here, OK?

Sending a lot of sound into a wall is not necessarily a good thing either...especially if it's a hard surface or worse yet, glass. 

I recently had an experience setting up a band in a club where one wall perpendicular to the stage was mirror.  All of the vocal mics were set up behind the main speakers, and all of them were behaving well except for the lead vocalist's mic...it was feeding back like crazy.  There were no monitor slants on stage (the band all used in-ear systems), and the mics closest to the mains were not having problems.

Finally, I starting suspecting that we were having reflection issues off the glass.  I used a laser pointer, and starting from main speaker near the mirrors, I scanned down the mirror.  At the edge of horn, I got a laser reflection that shot right back to the lead vocal mic in the center of the stage.  BUSTED!!  We angled that speaker cabinet in about 20 degrees, and the problem was solved.  The entire system sounded better in the back of the room as well.

 



If you're using monitor slants on stage, then this "aiming" thing gets really important.

First, you should be using cardiod patter mics (we'll do a post on just mic patterns on down the road).  For now, you just need to know that a cardiod mic is the least sensative to sound coming from the connector end.  So, you want to aim the monitor down the back of the mic in order to get the most volume from your monitors without feedback.

You'll still likely need to ring the monitor out with EQ (another post).  But this will get you started.

Don't forget about reflections coming off of the ceiling and back wall of the stage.  If you have a monitor feeding back when the performer steps away from the mic, that's likely your problem. 

I had that problem with one band in a normally problem-free room.  The back wall of the stage area was carpeted, but the band had hung a large metal sign directly behind the drumer and the lead vocal mic.  Every time the vocalist moved away from the mic, it was feedback city (and when I turned it down, it wasn't loud enough).  Moving the sign was not an option (egos at play here).  But, what I was able to do was angle the top of the sign out from the wall and moved the reflections down away from the vocal mic.  Unfortunately, I started getting all kinds of crap in the drum mics then and wound up pulling everything but the kick and snare out of the mix.  But hey, it was much more important to have that sign on the wall so the 5 people in the club knew who these guys were.

Here's one I came across earlier this year.  I had set up and rang out the monitor for one of the performers in a band.  I had it nice and clear and loud with no feedback.  However, he steps up to the mic and it's starts squeling uncontrolably.  I'm looking around at what could have changed, and after a few minutes it dawned on me.  He was wearing a cap with the bill down low over his eyes.  When he stepped up to the mic, the sound was reflecting off of the cap and into the mic.  He normally doesn't wear a cap during performance, so I had him take it off.  The problem went away.   So from that, we take away:

Ken's Road Tip #81:  Sound check it like you're going to play it.

That includes checking at the volume level you intend to play at (or actually, a little more).
It's a lot less risky to turn a system down during performance than turn it up to a level you haven't checked at.  And remember that people are really good sound absorbers, so they're going to soak up some of the sound during the gig.  At least, I hope you have an audience to do that. 

Next week, let's talk a bit more in depth about mics, and why you use certain mics in certain applications.  We'll talk about why they are one of the most important investments you make in a sound system.

And I'll leave you with a trivia question....
Q:  What's the best song to end your soundcheck with?

Send me your answers at itsjustlogistics@gmail.com.  Whoever gets it right gets a shameless plug and shoutout next week.

Until next time, keep the meters out of the red!

Ken
 

Ken Carver has been a musician and performer since the early 70's, and involved with live music production since the mid 70's. He worked for 15 years as a broadcast engineer, building numerous studios and transmitter sites around Texas. He's also worked in Critical Care Communications for the medical industry, R&D for an automated lighting manufacturer, and owned Project Lighting & Sound in the 80's. He currently heads up an R&D Hardware Technician Team at National Instruments in Austin, and still performs on the weekends in the Central Texas area. You can reach Ken at itsjustlogistics@gmail.com

Higher Ground

Last time, we talked about AC power and its obvious importance and impact on your show. If you look at a North American 120 volt outlet, you see three connection points....known as hot, neutral, and ground. The hot and neutral both have to be there in order for power to be delivered to your gear. But it's that third connection, the ground, that can either save your life or play havoc with your show.

Ground loops...almost everyone has heard of 'em. But, do you actually understand what's happening and why it's causing that loud hum in your equipment? Those of you who do...go get yourself a beverage and meet us back here in a few minutes. Everyone else, get ready to roll us your sleeves and delve into this mystery.

Remember Road Tip #3 from last time?

Thou shalt have one and only one path to ground.

First, lets dispelled a very common misconception about ground. Ground is a reference. It's not a value. So, most folks assume ground is zero volts. Well, it may appear to be in a lot of instances. But if you measure the potential between two different ground points, you're going to see a voltage of some magnitude. This is because we live in an imperfect world.
 

OK, here's a really common place for a ground loop to occur.  If you have a sound board out

front and your power amps on stage (as you should), then electrically it looks like this:

The natural thing for your sound man to do is to plug the console into the nearest outlet, but this is what you wind up with.  With a current flowing on the ground, the 60 Hz (50 for some parts of the world) will wind up being introduced into your main signal.  The further away the console is from the amps, the worse it is.  So, how do you fix it?

You have to break the loop somewhere.  And this is where people get into trouble.  They put one of those 3-to-2 wire adapters on either the amp or the mixer (which should just be outlawed because I've never seen anyone use them correctly).  Everything gets quiet and they thing they've fixed the problem.  And while technically they have "fixed" it, they've introduced a very serious potential problem.  

 

The ground wire in an AC power cord is generally 16 gauge wire, which means it can handle 13 amps without failing.  The ground wire in the mic cable that's connecting the mixer and the amp, however, is probably more like 22 or 24 gauge (as the numbers get bigger, the wire gets smaller).  The max current that wire can take is about 2 amps.  At that point, it's probably going to burn up.

 

So, in the event of a short, your ground wire in the mic cable has a good chance of failing...leaving the chassis of mixer energized.  Then when you touch it, YOU become the path to ground.  Not pleasant at all.

 

So, how should this be dealt with?  One way is to plug the mixer into the same outlet as the amp.  This means running an extension cord along with your snake, but if you've prepared your cables correctly then it's no big deal.

 

The best way is to lift the ground on one end of the audio cable (the blue wire in the diagram).  This is what I will do in permanent installations.  Typically, I'll leave it grounded at the console (since everything has to run through that) and lift it at the amp.  That's really the best solution, since everything now has a solid AC ground connection and the loop is broken.

 

There are other solutions available that will accomplish this with varying results.  Using an isolation transformer in the audio link will break the ground loop as well.  This is how you would use a transformer to break the loop in an unbalanced audio line.

The transformer couples the audio (the process is called "mutual inductance" if you really want to get your geek on and Google it).  But sinces there is not direct connection between the two devices, there is no loop.

The only downside to this is that unless you use a high quality transformer, your audio quality will suffer.  By the way...if you've ever wondered what's in a passive DI box, you're looking at it.

There are also "ground filters" out there which use a variety of methods to treat ground loops.  That are IMHO at best band aids, and at worse tourniquets (and you know what happens if you leave a tourniquet on too long).  Let the ground connections do their job protecting you...fix the loop on the audio side.

And now, the question of "why does the mic shock me"?  If you have your mic plugged into a mixer and then into an outlet, then all of those components are at one ground potential.  Then, you plug your guitar into your amp and the amp into an outlet.  Now you've got all of those things at another ground potential (unless you plug them into the same outlet as the mixer).  

So when you have your hands on your strings (which are also grounded on most electric guitars) and walk up to the mic and touch it with your lips, you've just completed the ground loop.  That wonderful tingle you feel is the current flowing!

How do you fix that?  There are a few things you can do.  Some people advocate putting capacitors in series with the ground wire in your guitar going to the bridge (and ultimately the strings).  I won't go into the math behind this (email me if you want to see it), but it still goes against my mantra of not jacking with a ground wire.

I've seen some guys carry their own "uni-ground" power distro systems.  It amounts to a series of outlet boxes that plug into an outlet close by, but only use the hot and neutral.  The ground wire then snakes between the boxes and ultimately ties to one plug.  It works just fine on paper, but it's a cluster to carry around and deploy.

The one sure way I've found over the years to solve the "gettin' shocked by the mic" syndrome is to use a wireless device...either with the mic or on your guitar.  Then, you've absolutely broken the ground path between the guitar and the amp.  There are some really decent wireless guitar systems out there now for under $200 (unlike my first one I got in the mid 80's for $2000).  Plus, you've got one less cable to tangle up on stage.

Next week, let's get back into the audio world (because let's face it...it's a lot more exciting than talking about power and ground).  In fact, I see a few weeks in sound world coming down the pipe.

And I've received a couple of emails asking this, so I'll bring it up here.  If there's something specific you would like to see addressed, let me know.  I've got a list of topics I'm planning to write about that goes into mid 2013, but they're in no specific order.  Feel free to drop me a line any time if there's a problem or situation you're trying to work through.

Until next week, keep the meters out of the red.

Ken Carver has been a musician and performer since the early 70's, and involved with live music production since the mid 70's. He worked for 15 years as a broadcast engineer, building numerous studios and transmitter sites around Texas. He's also worked in Critical Care Communications for the medical industry, R&D for an automated lighting manufacturer, and owned Project Lighting & Sound in the 80's. He currently heads up an R&D Hardware Technician Team at National Instruments in Austin, and still performs on the weekends in the Central Texas area. You can reach Ken at kcarvertx@gmail.com

More Power To You!

Ask any working band what's the most important thing they need for a good show, and they'll likely name off a myriad of items, substances, or mental states. And while something can be said for all of that, they'll likely miss something much more basic.

Namely, electrical power. 

Electricity...juice, power....whatever you call it everything from your vintage Marshall to your modern PA system needs it. We don't think about, because most of the time we just plug in and it works. But like the liquor you get from the bar...it can vary wildly in quality. And sometimes, how you plug everything in can make a difference as well.

When going into a new venue (or one I haven't played in a while) the first thing I do is assess the power situation. The things I want to know are: 

  - What outlets are live and wired correctly
  - What outlets are on what circuit breakers.

The first is pretty simple if you have an outlet tester like we described last week. The second is a little more challenging, but with the proper tool can be accomplished. This is where I break out the trusty circuit sniffer.

This device is actually sold for the purpose if identifying what breaker controls an outlet (and that's a handy thing to know if the breaker panel is accessible). But what I'll use it for is to figure out what outlets are on the same breaker. For the purpose of finding shared outlets, just plug in the transmitter and go around to different outlets with the "sniffer". If it beeps, the two outlets are on the same circuit. No beep...you've found a separate circuit.  Quite the handy thing to have...it will set you back about $40 at Lowes or Home Depot.

Electrical codes (for the most part) say you can have up to 4 outlets on a single breaker. What we want to do (at a bare minimum) is to try to find at least a couple of different circuits...especially if you're carrying any appreciable amount of lighting. The idea here is to get your sound on one breaker and the lighting another.

The advantage to doing this is two fold. First, you're more likely to trip a breaker with a lot of lighting than you are with your sound gear (unless you're just carrying an insane amount of both). If you do blow the lighting breaker, you don't stop the show completely.

Second, lighting tends to be more of a noise maker as far as the power line goes (it's referred to as Conducted Emissions in UL speak). Keeping your sound on a separate circuit helps keep some of this garbage from coming out of your speakers. We'll talk more in a bit about electrical power quality. For now, we're more concerned with quantity.

Grounding is one of those things that everyone has heard of, knows it's important, but really can't explain. There have been volumes written on the subject, and there can be some really hairy mathematics associated with the principles. If you want to know that stuff, it's out there. However, this discussion is all about putting a show on...not a math lesson.

A functioning ground performs a couple of important functions for us.

• In the event of an internal short in a piece of gear, it gives the current a return path other than you!
• It gives the noise, buzz, and hum that your cable shields pick up somewhere to go besides your amp.

The first is an obvious safety issue. This is why you've always heard that you shouldn't defeat or remove the ground pin on an AC plug. I know, this is where you tell me "...but my stuff hums if I don't do that." We'll talk more about that next time, but for now know that the reason you have a hum is because you have multiple ground paths and you have violated the cardinal rule in audio system grounding:

Ken's Road Tip #3 - Though shalt have one and only one path to ground.

  

Some clubs and venues have the power thing figured out. They will have a few dedicated circuits on stage for the bands use. Where you have to be careful is in those venues where bands were an after thought. If there are outlets on the stage area (ie; corner of the dance floor), it's quite possible they were run from the beer cooler, air conditioner, or the signs on the outside of the building (I've seen this one first hand). While your sound checking, listen to your gear for changes in sound quality, hums or buzzes that come and go, or any other gremlins that might plague your performance.

Of course, short of carrying your own power distribution system and pulling your power from the electrical service entrance (this is how we did it when we were carrying 64,000 watt lighting rigs), then you're at the mercy of the club wiring. The best thing you can do it make sure you have some decent amount of power conditioning/filtering between your equipment and the outlet.

Lets talk about what constitutes "decent" power conditioning. A decent power conditioner will provide a path to ground for noise that is on the lines prior to getting to your gear. It will also function as a clamp for any high voltage spikes that come along. Spikes...I've seen them as high as 300 volts on a 120 volt line. They happen when motors or compressors (the refrigeration kind) start and stop. They typically only last a fraction of a second, but the detrimental effects are cumulative. You want the conditioner to take the brunt of this abuse...not your gear.

  

A "decent" power conditioner is not one of those strips you get for 3 bucks at the check out line at Walmart. Those things might have some clamping in them, but they're typically so slow to react that the majority of the spike gets through before they kick in. Nope, this is one of those times where you get what you pay for.

Personally, I like the power conditioning gear from Tripp, Furman (not the RackRider stuff...it's crap unless you rebuild it), APC, and Monster. Whether you get the rack mount stuff or the power strips, make sure that you've got something protecting your investments.

Here's something that doesn't get mentioned much...power conditioners wear out! Yep, you read that right. Remember when I said that the damage from spikes adds up over time? Well, there's a component inside power conditioners that absorbs these spikes (it's called a "varistor" if you're curious) that does break down over time.

So how do you know when it's past it's prime? Some of the better conditioners have an indicator to tell you. For my stuff, I have the ability to check it on a test bench (which I do twice a year). For everyone else, I would recommend replacement every 5 to 10 years or if your gear has gone through a major electrical event (noticeable power surge, nearby lightning strike, etc). It's a lot cheaper to replace a couple of hundred bucks worth of power conditioners than it is a few thousand dollars worth of gear.

With more and more gear being essentially dedicated purpose computers, it's getting more and more important to deliver clean power to your equipment. One thing we haven't talked about is voltage regulators. These are a different animal from conditioners, in that their purpose in life is to make sure that you actually have 120 volts delivered to your gear...not 105 (less than optimal), or 140 (really bad).

Regulators actually turn the voltage up and down as needed to keep a consistent output. The really good ones use a multi-tap transformer, but they can be heavy and are expensive (typically north of $500). The less expensive ones perform the function using solid state devices, but the downside is they introduce their own noise. If you're carrying any significant amount of digital equipment (keyboards, mixers, etc) you owe it to yourself to look at adding voltage regulation to your set up. They even make a difference with tube amps, and help cut down on that "man...my amp sounded great earlier...what happened" syndrome.

Next time, we'll wrap up our discussion on power by going into more detail on grounding and the potential issues (there's a pun in there) that you can run into. And we will attempt to answer that age old question, "Why is my mic shocking the $#!+ out of me?"

Until next time, keep the meters out of the red!

Ken

Ken Carver has been a musician and performer since the early 70's, and involved with live music production since the mid 70's. He worked for 15 years as a broadcast engineer, building numerous studios and transmitter sites around Texas. He's also worked in Critical Care Communications for the medical industry, R&D for an automated lighting manufacturer, and owned Project Lighting & Sound in the 80's. He currently heads up an R&D Hardware Technician Team at National Instruments in Austin, and still performs on the weekends in the Central Texas area. You can reach Ken at kcarvertx@gmail.com