Lost My Balance...

There's a long list of buzzwords in audio that people toss around, but really don't understand what they mean.  Two of those terms are "balanced" and "unbalanced".  Now, if you're talking about your band mates...then everyone knows what you mean.  But if you're talking about an audio connection or interface...that's where a lot of people's understanding gets a little murky.  So, this week we'll try to bring some understanding to these terms.  I'll attempt to keep it light on the math and heavy on the practical applications.

First off, lets start with an unbalanced audio connection.  Every time you hook up a guitar to an amp, an iPod to a computer or mixer, or anything else that just uses a 2 conductor cable, you're using an unbalanced connection.  This is what that type of cable looks like:

A balanced connection requires three conductors.  If you're hooking up a professional mic to a mixer (especially if it's going down a long cable), then you're likely using a balanced connection. Here's what that type of wire looks like:

OK, we've identified the physical difference between the two types of cable.  But what's going on here electrically, and why is one better than the other.

Let's look at the unbalanced (also called single-ended) connection first, since it's a little easier to understand.  With unbalanced connections, the shield is performing two functions.  It's serving as the return path for the signal (the "negative" side of the audio if you will), and it's shielding the center conductor (the "positive" side) from external noise.  It does a pretty good job, but if the interference is strong enough, it's going to start bouncing the ground around...and you're going to hear that in the audio.

Here's a very basic premise...the shield is only going to do so much to protect the signal from interference.  Unless you're using wire with a solid outer shield (which would make the cable extremely stiff), then some amount of noise is going to get through.  And the longer the cable, the more chance for garbage to get in.  That's one of the reasons why you rarely see unbalanced connections longer than 30 feet.

OK, so why is a balanced audio connection so much better?  It has to do with the fact that there's a second line of defense against noise that's built into the architecture.  It's a concept called Common Mode Rejection.   No, I'm not talking about when you got turned down for dates back in high school.  This is far more useful and much less painful.

Before we talk about common mode rejection, we're going to have to have to touch on a mathematical concept here (sorry...I've put it off as long as I can).  That concept is Vector Addition.  OK...let that sit for a moment...the sting will go away.

The classic (and simplified) definition of a vector is a ray with magnitude and direction.  Putting that concept into a real world example...a car heading north at 50 MPH could be considered a vector.  You have both magnitude (50 MPH) and direction (north). 

So far so good, but how does vector addition work?  For that example, let's use a tug of war game.  Let's say that there are 4 people on each side of the rope pulling.  Pulling from the left side, it's 4 Marines.  On the right side, it's 4 members of the Austin Botanical Society.  When we say "go" there's force being applied from both directions, but guess which way the rope is going to go.  Yeah, I'm betting the that vector force coming from the Marines side is going to be a little greater.

Now, let's even this up.  We'll send the Botanical Society home and bring in 4 Army Rangers to stand in for them.  And now let's assume it's a dead even match and both teams are pulling with the same force.  Which way will the rope go?  Right, it doesn't move because the 2 forces are cancelling each out.  (Now, in reality I know that one team will probably prevail...but I have friends who are ex-Marine Corp and ex-Army...so I'll just let them talk trash to each other).

Back to the world of electrons.  A balanced audio connection works by running the same signal down 2 wires, but they're running opposite of each other.  If you've heard the term "out of phase"...this is it.

By the way, here's another tech term you can throw around and impress people.  Whenever you have two signals like this that are compliments (opposite) of each other, it's called a Differential Pair.  That's going to turn some heads at your next beer bust.

I know...you're thinking "if those signal cancel out, then how do we hear anything?".  Well, you're right, but this is just to show you what happens to two signals that are out of phase with each other when they're added together.  I'll show you how we recover the signal in a bit.

Now, we've got our two out of phase signals running down the cable.  All of a sudden, noise decides to show up and join the party.  Now, our otherwise pristine signal looks something like this:

I want you to notice something very important here, because it's key to understanding how we're going to get rid of the noise.  While our audio signals are out of phase with each other, the noise is the same (or in phase) on the 2 lines. 

So what do you suppose would happen if we could flip one of those audio signals over so that is was in phase with the other one.  What would happen to the noise? 

Now our two audio signals are in phase with each other, but the noise is now out of phase!  When we add those two signals together...the noise is cancelled out.  And just to throw another tech term out there for you, the specification that describes how well a piece of equipment does this job is called the Common Mode Rejection Ratio, or CMRR.  That's one of those specs where the bigger the number the better.

The "phase flip" and signal addition was done with a transformer in the olden days.  Now, it's typically done with a ....wait for it...differential input amplifier.  Electrically, what's going on looks like this:

Given this significantly improved method of getting rid of noise on audio lines (along with a couple of other electrical characteristics), we're able to run much longer cables without degrading our signal.  How much longer?  If you've got a good pro mic and you're plugging it into a decent mixer, you can typically run up to 2000' feet of cable before you start messing the signal up.  Yeah, you read that right...about 4/10ths of a mile!  This is why you have to used balanced audio connections when you have a console out front to mix the band.  In that application, it's not uncommon to have 120 feet of wire between the mic and mixer.

So, can unbalanced and balanced connections ever mix?  The short answer is yes.  You can unbalance a balanced connection through wiring:

You would use a cable like this if you wanted to plug a balanced microphone into a guitar amp.  You loose the noise cancellation and some signal, but it works.  When you do this, though, the rules for unbalanced wiring apply...especially the length of cable limits.

Going the other way from unbalanced to balanced can't be done through wiring alone.  You're going to have to have some electronics or a transformer.  If you're a bass player or keyboardist, you've like already used a device that performs this function.  You just probably know it by it's common name...a Direct Injection (DI) box.

The transformer does the job of converting the signal from single-ended (unbalanced) to differential (balanced).  It also electrically isolates whatever you're hooking up to prevent ground loops.  And again, this can be done with electronics to...which would make this an active DI box (as opposed to a passive one shown above). 

I want to leave you with one final thought here.  If you happen to have a balanced cable that's had one of the signal conductors fail, you will continue to get a signal through it, because that that point you've got an unbalanced connection.  It's going to be quite a bit lower in level, and likely have more noise on it (since you've lost the ability to cancel it out).  So, if you're setting up your PA and happen to notice that a mic is quieter than you expected, it's probably a good idea to bust out the handy dandy cable tester that I'm sure you have now and check that cable.

This is has been a pretty heavy installment, and I've only covered a small part of theory behind all of this.  If you have additional questions, you're always welcome to email me.

Next week, as long as were talking about these connection schemes we might as well tackle another "mystery subject" to a lot of people, and that's phantom power.

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

Seeing Specs Before My Eyes

Last week, we talked about all the ways that the wattage on an amplifier can be grossly overstated and that finding out the true power capabilities can be a game of cat and mouse.  This is especially true of the manufacturers of lower end gear.

This week, I wanted to at least touch on some of the other specifications you will typically see on a power amp.  You don't see these exaggerated near as much...mainly because most folks never get past the wattage spec.  But, they are there, and I thought you might like to know how them impact the way an amp sounds.

First off, let's take a look at the specs our trusty Crown XLS 802.

So, for a live sound application which specs are we really concerned with?  While I can make a case to consider all of 'em, the first 4 are really the important ones.  Let's talk about what they are.

Sensitivity Training
The spec for sensitivity of an amp is actually one of the easiest to understand.  The spec for this amp is 1.25 volts.  What that means is that if you turn the gain controls on the amp all the way up, it will take 1.25 volts at the inputs to drive it to full power.  This is a reasonable spec, as most modern mixers and crossovers can output several times this. 

The trick is that console outputs are almost always spec'd as dBu.  To convert that to voltage requires....ah hell, I'll just give you the answer today.  My Presonus StudioLive can do +24dBu.  That works out to a little over 12 volts...plenty to drive the amp.  (We'll do an article on decibels for non-math majors one of these days).

But decibels are funny critters, being logarithmic.  That means they're kind of like the Richter Scale they use for earthquakes...where a 7 is a whole lot worse than a 6.  If your console can output +18dBu, then that's about 6 volts.  And if it can only do +4dBu...that's right at 1.25 volts...which means you'll have to have it floored to max your amps out.  It also means you're completely out of headroom on your console and you're probably clipping the signal.
And once the signal clips at the console there's nothing you can do to clean it up later. ...you're S.O.L. at that point. 

Freq Out
The frequency response of an amp is the range of frequencies that it can pass.  Almost every amp will have that spec, but 80% of them are incomplete.  A frequency response without a tolerance on it is really useless.  The spec for this amp is 22Hz to 20kHz, but notice the numbers after that...+0 dB, -1 dB.  That means the amp is flat to within 1dB which is incredibly good. 

Most amps are spec'd +/- 3dB which is still perfectly acceptable for live work.  But when you start seeing numbers like +/- 10dB...it's a BS spec.  That means you're going to have to put a lot of EQ in front of that amp to get it to flatten out.  And if there's no tolerance...well...that just means they're hiding something.

Now, how much frequency response do you need for live work?  Unless you're using concert grade subwoofers and doing electronic dance music, you're not going to need to reproduce much of anything below 40Hz.  And going to the other way, most PA systems start rolling off at 12 kHz.

So why do amp manufacturers spec the frequency response outside of this range.  While you may not be able to hear (or a speaker pass) anything about 15kHz, an extended high frequency response can be an indication of how "fast" an amp is.  There's a spec not mentioned about called slew rate, and you'll usually see it on consoles and preamps.  Slew rate can be a scary looking spec, but what it amounts to is "how fast can this amp move on a waveform".  It's usually expressed in volts per microsecond.  An extended high frequency response can mean that the amp has a decent slew rate.  What that that translates into sonically is amp that sounds clear and punchy.  The slew rate along with the damping factor (we'll talk about in a bit) has a large impact on the "sound" of a power amp.

Bring Da' Noise
The signal to noise ratio (frequently abbreviated S/N) gives you an idea how much background noise the amp produces on it's own.  Here again, a bigger number is better.  For this amp, they're saying that the noise is 100dB below the signal.  Putting that into more familiar terms, it means that the noise is 1/100,000th of the signal...pretty darned quiet.  The difference between weighted and unweighted is that the weighted number is filtered and limited to what we can actually hear.  The weighted number is more meaningful in the real world here.  But even the unweighted is still pretty impressive. 

Again, how much do you need?  Keep in mind that your system S/N can not be any better than the worst component in the chain.  So, if you amp is 100dB, but your Behringer console is only 55dB...then that's as good as your system can get.  Personally, I look for 80dB or better unless the client just has no budget and is only going to be playing $#!+ hole clubs.

Distorting The Truth
When most musicians here the term "distortion" they think of the pedal a guitar player steps on before the intro to "Satisfaction".  (OK, bad example...that's a fuzz box). But where I'm going with this is that while distortion is usually desirable to a guitar (and some bass) players, it's not in a PA system.  So this is where a smaller number is better.

Now, how many of you actually know what "distortion" is?  The technical definition for the intellectually curious is any non-linearties introduced into a signal.  For the mere mortals, it's probably easier to explain how it's measured.

To measure distortion in an amp, you input a single tone (1kHZ is the standard, but some folks use 400Hz) and measure the output signal level.  Then, you filter out the original tone at the output and measure the signal level again.  The crap that's left over...that's your distortion.

Again, how much (or little in this case)?  It depends on the application.  If this amp were going into a studio or other critical listening environment, I would want 0.1% or less.  But for live work, I'll generally accept anything at 1% or below.  This amp has 0.5%, so it's fine.

But remember, for the distortion numbers to be meaningful it has to be a rated power.  And this is where you can get tripped up.  The Crown spec above is written to say that distortion will never be worse than half a percent.  But other manufacturers will bound the distortion measurement by doing things like spec'ing it at a lower power or not over the entire frequency bandwidth of the amp.

If you don't see this number on a spec sheet...it's likely because the manufacturer doesn't want you to know that it sucks.

Et All
The other numbers (IMD, Damping, Cross Talk, and Input Impedance) are still important, but unless you're putting a very large system together (I'm talking 10 power amps or more), don't concern yourself too much.  Most folks getting into a system that big are going to hire a geek like me to do it for 'em anyway.  But just for giggles, here's what they are and how the affect what comes out of the speakers.

• IMD - Intermodulation Distortion.  Dang...that hurt.  IMD is one of one of those distortions that is really uncool.  To explain it, you have to have a quick primer on the concept of Intermodulation.  Whenever you mix 2 different frequencies together, you wind up with 4!  Yep...it's magic.  You get the original 2, plus the sum and difference of them.  So..if you mixed 800Hz and 1200Hz, you would also get 400 Hz (1200-800) and 2000Hz (1200+800).  To bad we can't do that with currency.  Anyway, it's an annoying artifact, so the more negative this number is the better.
• Damping Factor - I would tell you how this number is derived, but you would just want to throw something at me.  Let's just go with this...the damping factor is an indicator of how well an amp can physically control a speaker.  Think about what's happening with a speaker...it's travelling one direction and then all of a sudden has to go the opposite way.  If the amp doesn't have enough control to do this, then the first thing you notice is that the low end is muddy and undefined.  The Damping Factor (sometimes written as DF) is one of those "bigger is better" numbers.  There are a lot of other things that affect the system Damping Factor (when you add in the speaker and the wire that hooks it up).  If you see an amp with 200 or better, you're in good shape.  Don't look for this spec on a budget amp...it would reek if they printed it.
• Crosstalk - This one is actually pretty easy to understand.  On a stereo (or multi-channel amp), the crosstalk is a measure of how much of the signal on one channel gets into another one.  Again, the more negative the number the better.  I only pay attention to this spec if the amp is going into a critical listening environment (like a studio).  But live...all the noise coming off the stage is going to mask the minor amount of crosstalk in the PA system.  As long as it's at least -40dB I'm not gonna sweat it for a PA.
• Input Impedance - This is almost useless to spec now unless you plan on hooking up 10 amps in parallel.  Back in the 60's when stuff had real transformers in it for the audio, this mattered.  Now...no so much.  It's just another big number to confuse the average user. 

I realize the last couple of weeks have been really tech-heavy.  Those of you who got through this...kudos.  Regardless of how much of this sank in, I hope this helps those of you buying equipment in the future.  Again, I hate seeing people get ripped off or wind up with less than they thought they were getting.

Next week...I promise no (OK...very, very little) math.  We'll talk about working with sound and lighting companies.  I recently played a show where we hired in the production (and man oh man was it nice to not have to pack a PA at the end of the night).  A lot of what we'll discuss also applies to playing on house systems at a club. 

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

Watts The Meaning Of All This

I'm going to let you in on a little secret about most consumer grade electronics manufacturers. They're counting on most people having absolutely no idea what all of those numbers on a specification sheet mean. They're banking on the fact that most people believe a bigger number is a better number.

Now before you beat yourself up over this, just keep in mind that unless you've got an electronics background and understand how specifications are derived then terms like S/N ratio and Total Harmonic Distortion are just buzzwords.

Furthermore, consumer grade audio manufacturers are really bending the rules nowadays...all in the quest of that all mighty big number. The pro grade guys...not so much. Because the guys that are ready to spend a few thousand dollars on a power amp can spot a B.S. spec in a split second.

So for the next couple of weeks, I'd like to impart a little bit of this inside information to you. We'll talk about what certain specifications are, whether a bigger number is actually better (not always), and how a spec affects how a piece of gear sounds. We'll also talk about the ways that manufacturers "fudge" the numbers...especially wattage.

I had originally planned to cover all of the major specs of a power amp in one article, but after I started writing this I realized that it would wind up being a very long post.  So we're going to split it up.  This week, we'll talk about wattage and power ratings.  Next week, the other specs.

Which Watt?
The output power of an amp is the most manipulated, massaged, and maladjusted spec on a power amp.  After all, that's the first thing people look at.   "Ooooo....2000 watts for just $100...I'll take it".  Yeah, you'll take it all right...but I'm not going to say where you're going to take it.

First, let me clear the air here. A watt is a watt...period. There are no "tube" watts, "solid state" watts, "British" watts, or "American" watts. Anyone who uses these terms falls under the category of "repeats whatever they read on bathroom walls". The formulae for calculating power does not contain a variable for any of these terms (but maybe there should be an "moron" variable). You hear these terms used with guitar amps mostly, but be aware they're out there and they're bunk!

There are several variations of the power formulae, depending on the variables that you know, but at the end of the day it boils down to this:

Power (watts) = Volts * Amps

 

 

Like I said, there are variations of that if you know the load that the amp is operating into.  The most frequently used is:

 

 

Power (watts) = Voltage Squared / Resistance (ohms)

 

 

You'll see that one written as P= E^2/R, and we'll be using that one later.

So with that said, lets look at a good set of wattage numbers, and then some not so good.

In With The Good
I consider Crown and QSC to be amoung the best amp manufacturers out there.  You'll see their amps on a lot of pro touring rigs, and the care they put into those high end products are reflected in their consumer grade stuff.  Since we've been talking about the Crown XLS 802 for the last couple of weeks, we'll give 'em a little more free advertising.

These are the average power numbers and are very conservative.  Most amp manufacturers use RMS (root-mean-square) power (which would result in a slightly higher number). Either measurement is a good indicator of what the amp can pump out all day long without breaking too much of a sweat.  Crown specs the frequency, the distortion level, and the loads they test into.  If it looks simple, it's because it is.  These are honest numbers without any trickery involved.

Taking A Peek At Peak To Peak
Prior to the mid 70's, amp manufacturers had no guidelines on how to spec power.  So how did they do it?  Easy, by using methods that would make for the biggest numbers! So you saw wattage ratings expressed in either Peak Power, or the notorious Peak To Peak Power.

So what are these numbers?  This is definitely one of those cases where a picture is worth a thousand algebra equations, so let's look at a sine wave:

The point at which the waveform crests and reaches it's maximum (or minimum) value is the peak.  Peak to Peak is 2 times that.

So lets say that I'm testing an amp into a 8 ohm load (typical for a loudspeaker), and I measure the peak value at 28.28 volts (there's a reason for that weird number).  OK, so how much power is that?  If you plug in the numbers you'll see:

 

(28.28 * 28.28) / 8

 

800 / 8

 

100 watts

 

 

So, the peak power of this amp is 100 watts.  Any guesses as to the Peak to Peak power?  Anyone?  Yep, 200 watts.  Sound pretty impressive, doesn't it.  But there's a slight problem with this number.

 

 

Not So Peak Performance

The problem with the Peak power numbers is that for most amps they're not sustainable.  What I mean by that is they can produce that power for a very short period of time (a few hundredths of a second).  If you tried to produce that continuously, you would burn the amp out pretty quickly. 

 

Looking at the sine wave above...you can see that the amp actually spends very little time (relative to the rest of the waveform) at the peak value. 

 

At some point in the mid 70's, the Federal Trade Commission finally stepped in and put some rules in place about how manufacturers can specify the power of their amps.  And with that came two new values...RMS and Average. 

 

Sustainable Power

RMS and Average values are what an amp can produce over an extended period of time without destroying itself.  So...what are they and how do they compare to the Peak numbers?  Glad you asked:

 

 OK...so that graph looks a little intimidating, but here's the bottom line.  The RMS (root mean squared) power is about 71% of the peak, and that is by far what most amp manufacturers use.  The average power is even more conservative, and is about 64% of the peak.  Crown uses the average power, but then again they've always been very conservative with their specs.

Hey Man, What Happened
So lets use what we just learned on the example I gave earlier.  Prior to about 1975, a manufacturer could have advertised the amp in my example as a 200 watt amp, and not told you how they came up with that number other than to say it was Peak to Peak.  But what can this amp really do?

First, anytime you see Peak to Peak, divide it in half.  Again...it's a BS number.  Now, take the 100 watts you have left and multiply it by .7, which leaves you with 70 watts.  That's a much more realistic number.  But what's more impressive...70 watts or 200 watts (sounds like one of those phone commercials with the kids, doesn't it)?  So now you know how the game is played.

Full Disclosure
A wattage rating alone is useless without knowing at a bare minimum the load you're operating into and the distortion.  The example from Crown, that's a complete spec.  But that's not so much the case with our next contestant.  And I don't mind calling them out, because Pyle is one of the worst offenders as far as manipulating their numbers and playing off the average consumer's lack of electronics knowledge.

What A Pyle Of...
OK, we saw a good wattage spec.  How's about something from the other end of the scale:

Two things to point out.  First, they are not doing anything illegal.  Second, keep in mind that they are advertising this amp as a 1,400 watt product.

Under the section for "Continuous Output Power", they list the amp as being able to produce 70 watts per channel into an 8 ohm load, and 110 watts into a 4 ohm.  That alone tells me that the power supply for this amp is under designed.  On a decent amp, it would produce about twice the wattage into 4 ohms as 8.  On this amp, the power supply runs out of gas before then.  That's a red flag.

There's another flag on this as well.  In the 8 ohm mode, they spec that the amp can deliver 70 watts over the full audio bandwidth (20Hz to 20kHz).  But, on the 4 ohm ratings, the 110 watt figure is only spec'd at a single frequency.  So that does that mean?  It means that the distortion figure likely goes to hell at frequencies above and/or below this.  That's a bad sign.

Anyway, we have power and load.  The Total Harmonic Distortion (THD) is listed as 0.1% at "rated output power".  So, that infers that it's at the 70 watt / 110 watt figures.  But then they throw out "Maximum Power" for the two loads.  And guess what, there's no definition for "Maximum Power" other than what they define.  Most likely, that wattage is at a higher distortion value...probably 1% (which still isn't terrible).

And then there's that Peak Power....which I'm at a loss on how they came up with.  If you take the 100 watt figure as an RMS value and work the math backwards, the Peak value I come up with is 142 watts.  So how the hell did they come up with 700 watts?

Hey Rocky, Watch Me Pull A Spec Out Of My A$$
Here's how they did it.  If you measure the power supply rail of the amp at idle, it's likely coming in at around 75 volts (a typical value for a 200 watt amp).  Now, if you plug that number into the power formula we used earlier, then you get:

(75 * 75) / 8

5625 / 8

703 watts

 

 

So in effect what they are saying is that the amp has the "potential" to produce a peak output of 700 watts.  However, there's a whole lot wrong with this:

• As soon a you put a signal in the amp, the supply rail is going to drop a bit
• Even if the supply rail didn't drop initially, it will in a few thousaths of a second
• Assuming they've got a really good power supply that maintains it's voltage under load(which they don't), you're going to have switching losses through the output transistors.

So the 700 watt spec is valid...until you actually try to amplify something.  That's real useful...not!

 

You should be on the lookout for other obscure power ratings.  There's no official industry definition for "Music Power".  Some manufacturers will make that 6 or 7 times their RMS and then come up with some tech-speak about non-recurring non-simultaneous power excursions in typical program material.  Screw you guys...you're trying to sell a 200 watt amp (on a good day) as a 1400 watt amp.

Levelling the Playing Field, And Then Not
As I said earlier, the Federal Trade Commission standardized how wattage could be advertised around 1975.  Amp makers either played by the rules or got fined for false advertising.

However, in the last couple of years the FTC appears to be bowing to pressure from electronics manufacturers.  They are now considering no longer requiring the distortion figure in print or radio advertising.  Their "rationale" behind this is a crappy as Pyle's power numbers:

• Most equipment produced today has a low distortion value.
• Most consumers don't understand that number
• Consumers that want to know the figures can find them on the Internet.

As to the first point, it should be noted that most equipment made today is capable of low distortion.  But if you're going to advertise it at a power level that 10x of reality...that goes out the window.  The other two points, I unfortunately can't argue with.

A Dead Give Away...
I've gotta give Behringer the "Most Exaggerated Wattage" award for their new iNuke series amps.  And here's why.

There's a basic law of energy conservation that says you can't get more power out of something than you put into it.  Keeping that in mind, and the fact that a watt is a watt regardless of how it's being used take a look at this spec sheet for what they claim is a 3000 watt amp:

There are a lot of numbers here, but I've highlighted the two of interest.  First is the claim that the amp can produce 1500 watts per channel into 2 ohms (and don't get me started on 2 ohm load measurements).  Then look down at the Power Consumption at 2 ohms...they're stating that it's 350 watts total.

If there's one number you can usually trust on a spec sheet, it's the power consumption number.  You see, if the manufacturer wants to get a UL (Underwriters Laboratories) sticker or equivalent, they have to state the max power the amp can draw under worst case conditions. 

So, what Behringer is saying is that they can put 350 watts into the amp, and get 3000 watts out.  Really?  Where did the other 2,650 watts come from?  OK...here's how they do it.

They're using the same trick as Pyle, and basing that 1500 watt per channel number on the power supply rail voltage (probably about 110 volts) The power supplies used in light weight amps (switching power supplies) can deliver a lot of power instantaneously, but can only do it for maybe a 1/10,000th of a second.  And then that's it...it's out of juice until it recharges on the next power cycle.  So it's a completely useless number other than for marketing.  If someone could make a device that could continuously output more power than it took in, they wouldn't be jacking around with amps.  They would be making trillions of dollars selling cheap energy to the world.

The bottom line here is that you can't have more continuous power out than you take in.  If you read anything to the contrary, it's more marketing BS.  In fact, the true power output of an amp should always be less than the power it draws from the AC outlet.  No amp is 100% efficient.  Some really good (and expensive) ones approach 90%...but most are in the range of 50% to 70%.  So, expect a true 500 watt amp to draw between 700 to 1000 watts.  The difference between the two figures is what's lost as heat.

Oh, and what do our friends from Pyle list as the power consumption for their "1400 watt" amp:

Wow...it's blank! Go figure.  Losers....

I realize we've covered a lot of stuff today, but to me this is important stuff.  I'm really tired of seeing decent working musicians spend their hard earned money with these companies thinking they're getting 3000 watts of power only to find out it's really less than 1/10th of that. 

In fact, it bugs me so much I'll make this offer.  If you're considering buying a power amp and you're not sure of what you're getting, then email me at the address below.  Either tell me the make and model or the amp or send me a PDF of the spec sheet.  I'll read it and tell you what you're really getting, not what the magazine ad wants you to believe.

Next week, we'll wrap up our discussion on specifications and how they impact the way an amp sounds.

Until then, keep the meters out of the red.  Especially if you don't have as much power as you think!


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

Nice Rack...Mount Equipment

When we left off last week, I was troubleshooting a mid 2000's Crown power amp that had decided to not work for a customer at a gig.  It turns out that the pots were a little dirty and the XLR input connections had fatigued.  A shot of DeOxit, some solder, and deionized air to blow the dust out and this bad boy is good to go.

While I had it apart, it really admired the construction techniques used.  Even though this amp was built in China, the attention to detail and a few little tricks to make the amp road worthy really stood out.

People talk about why one piece of gear is better than the other.  Sure, electrical specs are a big part of it, and we'll talk about how to actually read those in another installment.  But the bottom line is that if you're a working band and moving your gear from gig to gig, it's got to be able to stand up to that.  I've seen some equipment (designed for home use) that sounded fabulous, but wouldn't survive 10 miles in a U-Haul...even in a road case.

So this week I thought I would point out just what makes a piece of equipment "nice".  And even though we're just looking at a power amp, a lot of these points apply to any piece of electronic gear you're going to haul around.  And this is not an exclusive endorsement for Crown...there are a lot of other companies today building some very good gear at reasonable prices for the average working musician.  But on the other hand...there are a lot of 'em that are building some really bad stuff.

OK students...what is the #1 enemy of electronics?   What?  Who said heat?  That's right...proper system cooling goes a long way toward extending the life of the gear.  So that's usually the first thing I look at.  On that note, starting at the front panel notice the large vent for air flow:

 

And those aluminum fins that are sticking up...heat sinking for the output transistors.  The cooling fans are located directly behind them.  What all that adds up to is a straight path for the air to flow and take the heat out of the amp.  This is called back-to-front cooling, and just about every amp over 100 watts / channel uses that now.  But that wasn't always the case.  When I built my first really big PA (2,000 watts) in the late 80's, I used Peavey CS-800s.  They had a fan in the back, but exhausted the hot air out the sides of the amp.  Put 'em in a rack, and guess what...you're recirculating the hot air!  I had to hack up my road racks to get them to exhaust correctly.  It's something to watch out for.

Moving around to the back panel, check out the speaker connections:

This amp can output up to 800 watts per channel...far more than a 1/4" connector can safely carry.  Crown was one of the first companies to move to Speakon connections which are far more secure and can carry a whole lot of power.  Binding posts also give you the option of using banana plugs or wire lugs.  This is all standard on high power amps now, but this was cutting edge in 2006.

Moving across the back panel, Crown used two cooling fans for this amp:

Two fans give coverage to the entire heat sink field in the amp.  Electrically, they're two speed and thermostatically controlled.  They run at half speed (which makes 'em pretty quiet) until things get hot and heavy, and then they cut over to full speed.  And in the event that the amp still overheats due to a fan failure or extremely high ambient temperatures, the control system will shut everything down before any major damage can occur.  You're not going to find that on a cheap Pyle amp!

Inputs are pretty straight forward, a pair of balanced XLRs.  This is one place I've got to pick on this amp...it would have been really nice to have a switch that parallels the inputs.  In other words, let me plug into one channel, but feed both of them (useful if you're using the amp for subs).  I'm not crazy about the plastic housings on the XLRs, as those 4 screws you see (that go into the plastic) are what are holding that panel in place.  A couple of them were stripping out, so I used a filler on the holes to give the screws some new meat to bite into.

But you know what makes up for my gripes with the XLRs?  Look under the AC power connection.  That's not a fuse, it's a circuit breaker!!!!  That's right, if something happens and you pull too much power, this trips.  No fumbling around to find a replacement fuse...just clear the fault condition, reset the breaker, and you're back up and running.  In bulk, these really don't cost that much more than a fuse and fuse holder...and I really wish more manufacturers would go this route.

Now, there's a few things I want to show you on the inside of the amp.  If you remember from article I did a few weeks ago about rebuilding a bass amp, I talked about how the power supply is critical to the proper operation of the amp.  Check this out:

There are two things to point out here.  First, on the left, are the bulk storage filter capacitors.  There's about twice an many as theoretically required.  And that white stuff between them...industrial adhesive.  Components that are tall have a tendency to physically "rock" (not in a good way), and that can result in lead breakage and failed solder joints.  Gluing them all together helps prevent that. 

To the right, that round thing...it's a toroidal transformer.  This is what steps the line voltage down from 120 to the various voltages the amp needs.  Toroidals, because of their construction, have a very small magnetic field around them when compared to a standard rectangular transformer.  So why is that a big deal?  Easy, magnetic fields can induce hum into nearby audio circuits.  A transformer like this makes for an amp with very low background noise. 

There's one other construction note on this photo.  Right below the capacitors, you'll see a row of white rectangular objects.  Those are power resistors (we'll look at some different ones next).  These essentially balance the loads going to the output transistors, and they can get hot.  By selecting this style of resistor (which is relatively expensive), the heat is not going back into the circuit board and deteriorating it.  And notice a bead of silicone across the top of them...again to stabilize them and keep them from moving more than they should.

Finally, there's some construction points that the designers really got right on the circuit board.

There are three things I want you to notice here.  In the upper left, there are two power resistors (the grey cylinders with the stripes).  These are electrically the same kind of thing as the white rectangular ones above, but in what we call an axial package.  They're going to get hot as well, but if you look closely they're not sitting down on the circuit board (which would eventually scorch it).  They're set up off the board where they won't do damage and will radiate heat better.  That's a small thing that a lot of manufacturers miss.

In the top center is a ribbon cable that connects the front panel (pots and LED indicators) to the main board.  Remember last week when we had trouble with a ribbon cable because of the connector?  You won't see that here...the ribbon is soldered in!  It's more expensive because it increases your manufacturing build time, but you won't have a connector problem.

And finally, this is something I've only seen super high end touring amps.  See the red and black wires that are going into the board?  Those connections are stiffened with adhesive.  Otherwise, those wires would eventually break at those points (I've repaired plenty of them).  This cost a fraction of cent to do, but improves the reliability immensely.

This amp has a lot of other things going for it electrically that you can't see.  Things like a soft start turn-on (it reduces the inrush current when you power up), and a 3 second delay after turn-on before the speakers are connected...so you don't get that loud "THUMP" when you're bringing your system up.  And sonically it's just plain good,  but that's all in the specs.

So how about next week we talk about amp specs...what is THD, sensitivity, and damping factor?  How do these specs impact what the amp sounds like?  And probably most importantly, I'm going to show you how to spot a bogus wattage rating from a mile away.  You won't need a calculator, but if you're planning on drinking heavily next Friday night you might want to wait to read this one until Saturday afternoon.

Until then, keep the meters (or LEDs) 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

It's Only A Flesh Wound...

Most of us are at a performing level where we're still handling our own gear.  Some of you may have a small crew that handles the PA and lights, but there ain't many of us on the club circuit that have our own instrument techs.  Yeah, wouldn't it be wonderful to just show up for sound check with your tech waiting to hand you your guitar as you walk on to a 60' x 40' custom stage. 

OK...wake up.  It's time to load in.

This week, I want to talk about personal safety for musicians that handle their own gear before and after a show.

As a musician that's moving equipment in the afternoon and then performing at night, you want to make sure that you protect your hands and limbs, your back, and then everything else. 

You're In Good Hands...
Let's start with the hands.  Unless you're a vocals-only front person you're going to need your fingers to play your instrument.  Moving cases, handling cables, and everything else that goes into building a production has the potential of doing damage.  So to that end, get yourself a pair of good quality well fitted gloves...and wear 'em!  My favorites are Setwear Pro Leather gloves.  They'll set you back about $40, but they typically last a few years for me.  If that's too rich for your blood, then get a set of mechanic's gloves (about $15 at auto parts and home improvement stores).

Whatever you get, make sure they fit snug.  Gloves that are too large for your hands will just frustrate you, and you'll likely not wear them.

Fingerless gloves have their place, but not moving equipment.  Back in the days when we were carrying lighting truss, I had a pair that I used for just that task.  I could thread the hardware easily, and my palms were still protected.  But other than that and weight lifting...they really don't do much for a rock-n-roll show (unless you're a lead singer in an 80's tribute band...then knock yourself out).

That's How We Roll
Never carry something that you can roll.  If you've got a road case with good casters and it's not ridiculously heavy put a small container or two on it when you get it out of the truck/trailer...then head for the stage area.  As a bonus, you can save yourself a few trips to back and forth if you watch what you're doing.

If you don't own a good hand truck, you're working way too hard.  I don't like wheels on a PA or sub cabinet (unless they're removable).  So if they're not in a case or on a dolly board then put those bad boys on a hand truck and off you go.  If you're carrying them by hand, you're straining yourself.  If they're big enough for two people to carry....we'll, you're tying up two people when one person and a hand truck could do the work.

If you do outdoor gigs where you have to go over rough terrain, then get a hand truck with pneumatic tires.  But, that does mean you will need to air them up periodically so you better have a tire pressure gauge and air compressor.  The solid-wheel versions are fine until you have to go over soft ground.

One of my hand trucks is a convertible type, where you can make it a 4 wheeler to carry more gear.  That configuration is OK if you're on smooth asphalt, concrete, or flooring.  But honestly, almost everything we have has casters on it, so we don't use that option very often.

A good hand truck will run you around $60.  Again, the home improvement stores (Home Depot, Lowe's, etc) will have 'em.  I bought my workhorse at U-Haul for under $50 (they will deal a little on the price if you're nice about it or a regular customer). 

Now, if you're a drummer, keyboardist, or anyone else with a lot of bulky (but not overly heavy) cases, then you owe it to yourself to check out Rock N Roller carts and hand trucks.  I know two drummers that have these, and they're great.  They don't seem that heavy, but they can take a beating.  There are a bunch of different configurations and options for them (some of them a bit overpriced, but whatever).  But think about this...instead of four or five trips to the truck, you load up and bring everything in with one trip!  Think about how much time you've saved.

Back Up Against The Wall
I'm a text book example of back problems.  Between falling out of trees when I was a kid, and then breaking my back about 10 years ago...yeah, I've got issues.  There's no substitute for being careful, but if you've got a history of back trouble, are over 40, have a lot of heavy stuff (or in my case, all of the above), then get yourself a back brace to wear while moving things around.  I got mine at Home Depot for less than $15...and that's less than half of my deductible for one chiropractic treatment! 

I like the braces with the shoulder straps so I can loosen it when I'm not lifting things, but it's right there when someone asks for a hand with something.  It's not the coolest or sexist thing you'll buy, but this is all about you and being able to play later.

And Then There's That Gravity Thing
If you're working outside and especially on uneven surfaces, beware of cases that decide to start rolling on their own.  That happened to us last weekend on a concrete patio we were playing.  A Mesa Boogie guitar amp took a spill (but survived)...but that could have been bad.  If you've got good casters and they don't have brakes then make sure to block the case so it can't go anywhere.

If You Want Blood...
With all the care in the world, accidents still happen.  I got the end of my fretting hand index finger sliced right before a gig a few weeks ago.  If I had still had my gloves on, it wouldn't have happened.  But it did, and so I had to fix myself up. 

I keep of bottle of what I call "skin fix-it" in my work box.  It's marketed under the name New Skin or Liquid Bandage, but it's all the same.  It's basically a medical grade Super Glue with an antiseptic in it.  I buy it at CVS Pharmacy.  Unless you're a total klutz, a bottle will last you for years.  It works best on clean cuts.  Take your time and build up several layers of the stuff and you can get through a gig.  A puncture wound, though, it ain't gonna help.  The only thing you can do for that is Neosporin, a bandage, and a shot of Patron.

You know those rustic looking stages finished in rough cedar that are a main stay at Country Western clubs and upscale venues?  Any club owner that puts those in needs to be thrown into a cage with pissed off porcupines.  Those things are splinter bombs just waiting to go off.  I got one over an inch long under a fingernail about 5 minutes before a very high profile show.  That was a long 3 sets.  Now I keep a set of fine point tweezers in my gig bag, along with fingernail clippers and a file.  Hang nails and guitar playing don't work.  (And no...I quit carrying the black nail polish a long time ago).

Don't Start Killing Brain Cells Early...
I have a personal rule when setting up a show.  I don't have that first beer until everything is unpacked, stacked, and hooked up...especially the power hook ups.  You get hurt when you're not aware of what's going on around you. 

For the next couple of weeks, I want to talk about the actual load in and striking the show.  It amazes me how many bands create multiple obstacles for themselves when they're moving gear in and out of a venue.  I've got a couple of full production shows with The Rhythm Dawgs over the next couple of weeks, so this is a good time to share some of the things I've learned over the years.

Until then...keep the meters out of the red (especially if the red is blood).

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, Setlist, Go!

"What do you want to play next?"  

Seven words that will bring a band's show to a grinding halt.  This is one of the differences between just playing a bunch of songs, and putting on a show.  Learning the songs and rehearsing them is a large part of the equation...but putting them together is the final polish a lot of bands miss.

Enter the set list,  our musical road map for the evening.  Sure, some bands get by just fine without one.  Heck, I've been a hired gun a couple of times where the band leader just held a certain number of fingers up or down to indicate the key of the song and off we went.  But for the most part, the "show" bands I've been involved in always have a set list done ahead of time.

The more people that are involved in a production, the more important the set list becomes.  If you're a trio, the fingers up/down thing works.  But what happens when you've got 5 or 6 people on stage?  Then add a sound man.  Add a lighting person with a programmed show, and they really need to know what's coming up next.  And that's not even considering if you're a band that uses backing tracks...you don't need to be hunting for the right track between each song...they should all be lined up and ready to go.

OK...I've made my argument for making a set list.  So, how do you go about doing it?  For some bands (like The Rhythm Dawgs), it's a group effort.  We'll all get together a week or two before a show and discuss what we would like to play that night.  We'll look over our master song list (you've got one of those too, don't cha?) and see if there's anything we haven't played in a while we would like to bring back as well as any new material we would like to try.  Plus...it's a good excuse to get together, have a beer or 4, and a few laughs.  I'm proud to say that we've managed to write a different list for every show we've ever done. 

Other bands I've been a part of, it's been one person that takes care of it.  For me, this is cool as long as I get a copy of it a couple of days before the show so I can add my performance notes and get the songs ordered in my iPad.

There are pros and cons to both methods.  The group effort method takes a bit of every one's time, but you also get to discuss things like "I've got to change guitars after this song", or "that's 3 really high songs I've got to sing in a row...can we break those up?".  The one-man method gets it done with less work from the band (and usually goes quicker), but you loose that "logistics" feedback.  On those, if I see something really hokey...I'll usually shoot an email back saying "OK...you've got me changing guitars 3 times in 3 songs...are you cool with that?".  At least you've made them aware.

What goes on a set list?  Obviously, the name of the song (duh).  We like to put the key of the song as well.  If we're going to run 2 or more songs together (more on that in a minute), then that should be indicated as well.  After that, I've got my own notes I always add. 

This is actually part of the 4th set from The Dawgs show in Georgetown, TX last night:

The first 3 columns have the set/song number, the song, and the key.  This info gets sent to everyone (so we're all working off the same list).  The next 2 columns are information I add that's specific to my performance needs.  Namely, which guitar to use and the patch to call up on my guitar rig.  On the third song, you'll notice I have the note "Open G".  The guitar I'm using (a Fender VG Strat) has electronically altered tunings on it.  You gotta be in open G to do the Keith Richards thing right.   I've seen drummers add tempos in beats per minute.  Anything that helps you execute the song,,,add it in.

So...how do you pick the songs and order 'em?  There's as many theories on that as there are bands.  This is how I've done it for years in my bands that play predominately cover songs, and it seems to work pretty well.

Think About Where You're Playing
If it's a club date and you're starting late, then people are probably going to be tanked up already and want to dance.  Don't hold back on 'em, but don't waste your money shot on the first song either.  I like to start the evening out with a mid-tempo tune that's familiar to 'em.  Think of it as "breaking the ice".

That said, if I'm at a venue that has a earlier start or maybe has people still having dinner, then I will restrain things a bit.  I don't have any 40's or 50's lounge music in my catalog, but I'll lean to the bluesy side of things or some of the lighter Top-40 of the 60's & 70's (if it fits the age group there).

Ebb & Flow
In a typical one hour set, you'll probably play about 12 songs unless you fall into one of these categories:
 - You're a jam band.  In that case, you'll play 2 or 3 songs and you can stop reading this now.
 - You're a  Ramones tribute band.  In that case, you'll play 25 or 30 songs in that hour.

You should be building the energy a little bit with each song.  Don't jump the tempos and intensities all over the place...have some flow to it.

Always keep the entire night in mind.  Most places have a "peak" time...the time everybody's into the party, but before they have to leave to get home before midnight (and get he baby sitter home).  You want to load your strongest material in the slots that corresponds to that time.

Gimme A Break
If you're a dance music band, you probably want to keep things building throughout the entire set.  Personally I like to see, as my partner in crime Dana Vandiver calls it, a "reduced intensity" song in the middle of the set.  It breaks things up and provides contrast.  It also gives people a chance to order more drinks (after all, we here to sell booze first and foremost).  The Rhythm Dawgs originally started doing this to give our drummer a little breather in the middle of the set, but it turned out to work so well we always put 'em in.  And of course, the only dancing that most white people can do correctly is "slow", so there you go.

Intensity vs Tempo
Notice we said "reduced intensity", and not necessarily a "slow" song.  They can be the same thing, but don't always have to be.  A song can be slow and still be intense...Sad But True by Metallica is a good example. The tempo is only about 100 beats per minute, but it's really heavy.  At the other end of the spectrum would be something like Get Together by The Youngbloods.  That moves along at a pretty good clip (about 125 BPM), but it's more a ballad than a rocker.

You can think of intensity in terms of how dense the instrument arrangement is, or how aggressive the tones and the vocals are.  Once you start thinking about more than just the tempo of the songs, you'll really be able to craft a great set list.

Keep It Moving
I've always tried to play the first 3 songs of a set back to back to back.  After that, we'll stop and do our "Good Evening" thing with the crowd.  It's a powerful way to start a set, but you have to make sure to plan for it.  If someone has to stop and change guitars it kills the effect (unless the rest of the band can cover the intro while they change...but you work that out ahead of time).

And as far as that "guitar change" thing goes, try to make sure that everyone isn't changing at the same time.  There should always be someone available to talk to the crowd, whether it's just the "are you doin' alright" stuff or promoting your merch.  Dead air...it sucks.  Don't have it.

Have You Seen My Keys
Earlier I mentioned that I like to see the song key on a set list.  During the performance, it's a nice reminder (especially if I have to use a guitar with an altered tuning).  But it's also useful as a debugging tool while writing the list out.  I you see that you have 3 or 4 songs in the same key, you might want to switch some things around.  Non-musical people might not can tell you why, but the songs will start sounding the same after a while.  

Remember what I said about building the energy during a set?  The key of a song can help do that.  When you have 2 songs with about the same tempo, it's going to sound more energetic if you move up in keys in the order.  In other words, if you have one song in A and the next in C, put the song in A first.

Don't overlook an opportunity to run two songs in the same key together every now and then.  Did you know that Folsom Prison Blues by Johnny Cash, and George Thorogood's I Drink Alone make a dandy segue?

Finish The Set Strong
After the reduced intensity, it's back to building up for a big finish at the end of the set.  I always try to have something strong, on the intense side, and a crowd favorite to close out a set.  And for me and my guys, it's a plus if we can stick a B.S.E. (Big Stupid Ending) on the end.  You know, the drawn out note at the end over which you shout "We are (insert band name here).  We're going to take a quick break and be right back...be sure to tip your bartenders and waitresses" speech.  Yeah, it's been done a million times, but it works (and the staff appreciates the mention for tips), and it gives the set some closure.

It's always kind of been a pet peeve of mind when bands end a set cold and just walk off.  The audience is left sitting there like...."that's it?".  It's kind of like the time your date got up to go to the bathroom and never came back.  OK, maybe not that traumatic, but still somewhat unsatisfying.  

Don't Be Redundant & Repetitive
Be aware of sound-alike songs in your catalog.  You don't want to play LaGrange and Boogie Chillen back to back...same song.  And if your song list is diverse enough to include He's So Fine and My Sweet Lord...you get the idea.  And heaven forbid...don't ever play The Alphabet Song right after Twinkle Twinkle Little Star...people will think you're crazy.

Even if they're not copies of each other, be aware of playing the same rhythm over and over for several songs (unless you play House or Trance music...but then again you really don't need this information then).

Read The Room
Unless you're playing arena shows with a 40-person crew that has to coordinate lights, backing tracks, lasers, pyro, and a flying gag all in one song...then you have to leave yourself the flexibility of changing things around.

There have been nights that we wrote out this great rock-n-roll show, but the crowd that particular evening was in the mood to hear blues.  So that's what we pulled out.  During the first break, we re-wrote the set lists and gave 'em what they wanted.  Likewise, if someone asks for a song that you know how to play (and puts a $10 bill in the tip jar) you're going to play it whether it's on the set list or not.  So you figure out what to drop and move around.  Don't be afraid to swap things between sets...especially if someone is giving you money for it!

Along these lines, make sure you have a master song list handy in case you need to switch things up...that saves the "what do we know" discussion.

We've got a master list that's divided in different categories:

 - Songs we can play at the drop of a hat
 - Songs we could play if we talked about a second
 - Songs that require rehearsing them in the parking lot
 - Songs that we were obviously drunk when we picked 'em

Watch Your Backs
Just because you've indicated that you're going to run 2 or 3 songs together on the set list, make sure everyone is ready before starting each one.  Strings break, kick drum pedals come apart,  shots need to be drank.  Make sure everyone has made eye contact before moving on.

We'll Be Back
You always want to plug when you're going to be back at a venue, but trying to remember that date along with everything else you have to keep up with can be a bit of a challenge.

Once again, I've gotta give credit to Mr. Vandiver.  In the Dawgs, he's the guy that formats the set lists and sends 'em out to everyone to edit for themselves.  He now adds "Return Date:  xx/xx/xx" at the bottom of each page.  Freakin' genius.

Thank You Very Much...Good Night
Again, this is just one set of opinions that happen to work for me and the bands I've been associated with.  The idea is to minimize the dead time between songs and keep the show moving along (and interesting).  

If your band is rehearsed well enough and everyone can set up quickly enough between songs, then maybe you don't need this.  But for me, the less thinking I have to do about the stuff around the songs, the more I'm able to concentrate on (and enjoy) playing the songs themselves.

I've recently received a few emails asking "how do you learn songs?".  For me, it's actually a bigger challenge to learn bass parts on a lot of songs than it is guitar...just because it's usually harder to pick out the nuances with a busy arrangement on top of it.

Next week I'll share with you some of my techniques for learning parts, as well as some of the software tools I use.

Until next week, 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