Ultimate Guide To Going Live. Part 4: Amplification

A guide to knowing how much volume you'll need at a gig, and what kind of power rating you'll have to use.

Ultimate Guitar
When you're doing a gig, chances are, you're going to have your amplifiers mic'ed up to a P.A. system. However, this doesn't mean you will be able to get away with a flimsy 15 watt solidstate amplifier. I'd suggest that you at least have a 50 watt solidstate amp or a 20 watt tube amplifier. In either terms, an amplifier with one 12" speaker should be the absolute minimum. Gigging with an amplifier that has two 12" speakers is more reliable, because you won't have to crank the amplifier to hear yourself onstage.

Volume Levels

The first issue to deal with is how loud you need your rig to be. The first step you need to take is to be louder than your drummer. This can be determined at band rehearsal. If you're rehearsing or just jamming with your band, everyone should be heard clearly - this includes the singer through the microphone. Your sound in the rehearsal room should be nice and clear, no mud or "fuzzy" areas of the sound. If you notice sounds starting to blend in a bad way, take a few steps to fix it. First, have your drummer play a simple beat at a comfortable volume level. Then, have your bassist start playing at a normal and relaxed volume. Have one guitar (if you have two guitars) enter. Once you identify which instrument the mud is coming from, take corrective measures. Some examples include turning down the gain, correcting the EQ on the amplifier, or taking further steps such as replacing worn out tubes or bad volume or tone pots. Keeping your gear in top shape for a gig is essential. Once you've got your mud cleared up, you need to know how loud you need to be at a gig. Here is a quick introduction to sound pressure levels and their qualities. Remember "volume" is merely the amount of sound that the ear can detect.
  • Volume decreases by 6 dB when you double your distance from the source. This means if you are standing five feet from your amplifier, it will sound noticably quiter when you are standing ten feet away from your amplifier.
  • Volume increases by 3 dB when you double the power to a loudspeaker. If you have your volume control at five on your guitar, it will sound 3 dB louder when you have your volume control at 10
  • Volume is perceived to be doubled when the amount of signal entering a loudspeaker is increased by a factor of ten. This means that a 500 watt amplifier will sound twice as loud as a 50 watt amplifier on full blast. However, this is merely perceived this way, and it is not a true doubling of volume. In fact, it is only an increase of 10 dB. Simply put, an increase of 6dB from an amplifier is heard as a 30% increase, but lowering the volume by 6dB is heard as a 20% decrease in overall volume. An increase of 10dB is heard to be an increase of 100% volume, but a decrease of 10dB is heard to be a decrease of 50%. This is all approximate, and the actual volume varies from ear to ear.

    Applying Sound Pressure Levels

    To apply sound pressure levels to an in-person situation, you need to have a decent understanding of various noises and their approximate dB level. 0dB is considered to be the theoretical point of "no noise", while 130 dB is the average threshold of perceiving pain from loud noise. Think of when two girls meet with exciting news in a school hallway (painfully loud), compared to a library when you can almost hear your heartbeat. Here's a simple list of noises and their volume levels: - Whisper: 15 - 25dB - Quiet Background Noise (rustling papers, coughing): about 35dB - Normal Home Or Office Background: 40 - 60dB - Normal Speaking Voice: 65 - 70dB - Jazz Trio (drums / acoustic bass / grand piano): 95 - 100dB - Loud Orchestra/Big Band: 105dB - Live Rock Music: 120dB+ (this is also approaching the nominal threshold of pain) - Average Ac/dc Concert: 130 - 140dB - Jet Aircraft: 140 - 180dB - Space Shuttle Launch 198+dB (close to the theoretical limit of hearing) Now, when you think about it, a noisy bar where you are likely to play will be about as loud as an orchestra reaching a loud point in music. Fairly headache inducing, plus the echo. Your job, as your band's gear technician (if you hold that position) is to create the ideal level of noise that overpowers the band, but does not cause people to have a migraine. So, the noise you want to aim for is just under 120dB. Simple enough, right? Not so. However, as a playing band, people are likely to pay attention to you. This can be good and bad. During playing, the bar will be quieter than when you aren't, so you can probably hit it off with a 100 - 110 dB level. However, at the end of a song that really hits it off with the crowd, you are going to need to get those amplifiers burning, so you'll at least need 120dB to get the final few bars of a song heard properly. In order to compensate for the situation, have the bar's P.A. manager understand your songs. Give them a sheet with times in the song when you need to have the volume go up and down. The P.A. manager should be able to detect when your band is getting drowned out on his own, but if your sound has certain needs (like you want an acoustic ballad to be softer), then you need to run it through with him quickly, and make sure you have a fully printed off and easy to read sheet for him to hold. Besides that, you want the band to be on good terms with the P.A. manager. He can be your best friend, or your worst enemy. And as a musician, you don't need any more enemies than you may already have.

    Speaker Units

    Consider a speaker unit as one enclosed series of speakers. That means the 412 stack that goes with your amplifier head, or the P.A. units that blast the sound out to the crowd. Ever wonder just how much sound those make? Well, here's an explanation. First, consider this: the term "speaker unit" may differ. Generally, the amount of watts going into the speaker determines the amount of volume. So if you have a 100 watt amplifier head going through a 412 stack, simply look for the proper watt rating. Two 100 watt amplifiers going through seperate speaker units will equal to 200 watts, simply because the different sound pressure levels add onto each other. Sound varies by 3 dB when you double the amount of equally powered speaker enclosures. This means that if you have one 12" speaker running at 100 watts of power, running another amplifier at 100 watts with a 12" speaker will increase the total volume by three decibels. The same rule applies to an amplifier with two 12" speakers. Having another amplifier run at the same watt rating with two 12" speaker increases the total volume by 3 dB. As if you need to get any louder. - 1 enclosure unit running at 10w produces 110dB of noise at a distance of only 1 meter. - 2 enclusure units running at 20w produces 113dB of noise at a distance of 1 meter - 4 enclosure units running at 40w produces 116dB of noise at a distance of one meter - 1 enclosure unit running at 100w produces 120dB of noise at a distance of 1 meter - 2 enclosure units running at 200w produces 123dB of noise at a distance of 1 meter - 4 enclosure units running at 400w produces 126dB of noise at a distance of 1 meter The key to using the data is to remember how sound dissipates over distance. The general rule of thumb is that volume decreases by 6dB - a fairly significant decrease - when you double your distance from the source. So, suppose that you have to project your sound over a distance of 20 meters. Your combined amplification is 400 watts of four amplifier units. For simplicity's sake, P.A. units aren't being considered. Now, 126 dB is being produced at the front - that includes you. So you, as a performer, are in serious pain from the noise. The front frow, two meters away from the power source, are hearing only 120 dB - still plenty loud. Getting four meters away from the source, the crowd hears 114 dB. Eight meters away, the crowd hears 108 dB - this is still a fairly comfortable noise level. Sixteen meters away, the crowd hears 102 dB. Over here, people are likely to be talking to each other, igoring the music. So, really, this seems ideal, right? Well for small gigs where you don't need to blare the volume, it may be okay, but if you think you can get away with this at large gigs, you are simply mistaken. As a musician, you have to be comfortable onstage. And when that much noise is being pumped into your poor little eardrums, you're in trouble. You have to protect your ears very carefully. Steve Vai has said that you should protect your ears with more caution than you should your dick. And I, for one, would take this caution carefully. Ever had to sit in front of 20 trumpets blaring away in a small room? I have. Add to that 15 trombones. Going home, my ears were simply numb and almost ringing. No biggie, right? It's just temporary damage. And I only had to endure about 3 nights of that kind of playing. However, when you're seriously gigging musicians, you have to be more careful. Your ears are the most important part of your skill. This is where P.A. systems come in, which will be dealt with in the next article. Remember, as part of your live gig, to carry plenty of earplugs. Even when you have monitor systems, bring earplugs. Wear them. As long as you can comfortably hear your music, and your voice clearly, protecting your ears is an absolute must. In fact, it is a good courtesy to have a basket of inexpensive earplugs available for fans to wear at the front if they want in on the action of you playing, but don't want to lose your hearing. It's simply good etiquette. You might want to talk it over with the bar owner about earplugs, and that if possible, that they could deduct about 20 dollars of your payoff and buy a bulk package of styrofoam, one-time use earplugs for fans. 20 dollars isn't much divided among four or five individuals, and you rely on your fans for money. Treat them as you would like them to treat you. Always provide proper grounding, and bring volt-meters and ground testing as part of your amplifier setup. Make sure you aren't overloading one circuit, so talk over the electronics of the establishment with the bar owner. Follow all instructions on voltmeters carefully. It could save your life. Keep on reading the Guide to Going Live series, where I will continue on the subject of projecting noise using P.A. Speaker setups. Thank you for reading my article, and I hope anything you've learned will serve you well. I'll be happy to answer any further questions you have. Peace Out, - Backup Guitar
  • 56 comments sorted by best / new / date

      I didn't understand a word of that, wow, way too technical for me. I'm sure if i could understand it it would be good though.
      fender rocker16
      yea um i understood a bit of that but most of it was too complicated. o well good article anyway. i bet it helped all you smart people haha. thanks for not writing an opinion piece of shit article. yea you all know what articles im talking about lol. they do get old lol
      dB stands for decibel. Decibels are the units used to measure sound. I know he didn't say that outright but you can figure it out easily if you read the article. Come on, people.
      nice article, a great help for my upcoming gig. im only 12 btw...
      me an my gitar
      sounds like you know your stuff. props on that. you could have broken it down to layperson terms a little more, but overall you gotta be pretty stupid to not get the point of it
      Ax Man
      NovaHawk: Your right about adjustin your amp my basic point is that tubes are more touchy...And they don't die after one or two gigs...BUT everytime the tube amp is turned on you have shorten it's life. And for the record the soild-state amp is much more road worthy...Trust me on this one, I've blowen several tube amp 'cause the tubes didn't have time to warm up, 'cause we had a flat on the bus and by the time it got fixed and we got to the gig...well that's just say we were pushed for time, but the show did go on, and ya it was on time too.
      I have a 4x10 Fender Deville. Is that big enough to play live with a P.A. hooked up?
      i didnt think that was comlex at all i only been playing 9mths and i understood it but hey we all cant be as smart as me right?
      Ax Man I beg to differ with you on the Tube and Solid state setting issues live, every amp takes tweaking no matter where you are, and what they are made of. Also Backup, I think that would make a real good article about the perceived volume differences between tube and solid state, not many people realize it but tubes are actually PERCEIVED to the ear as being louder than a solid sate, while a meter says they're identical. Your ear is an amazing thing.
      Tom Martin
      A dB is a decibel (sp?) it's a measure of volume. I would have thought that would be obvious even if you didn't know what it was.
      a little confusing in the beginning, but it all wrapped up in the end. 5 for you. keep 'em coming backup
      ok this is a stupid question and should be commen sense but...what does P.A. stand for?
      One question: If your sound decreases by 6dB every time you double your distance then if you are standing 20 feet away and move to 40 feet abay you'll still only lose 6 decibals?
      lol IO can't beleive that. I have not clue what P.A. stands for now that I try to think of it either.
      Almost Imfamous
      i think pa means public announcment. its the systems used for speaches and such.a microphone hooked up to a mixer hooked up to speakers. correct me if im wrong.
      this should be recquired reading for guitarists, way too many have their amps at 11. Its really not that hard to comprehend, its very basic math, but I suppose thinking isnt quite punk-rock.
      Great article, man. All the dolts that dont understand a word for it, hes pretty much giving you a chart/idea to base it off of, and to base what kind of gear(power essentially) you will have to look for/purchase to be a good live band. GOod live bands get picked up before crappy ones to be swept off to get a record deal. Great articles, I will continue to read them
      Backup Guitar
      Nope, there's no such thing as 0 dB. See, your blood rushing through your veins makes a noise - generally you can hear that under 15 dB of noise, therefore making it impossible for you to hear anything under 10dB. Of course, you have to be in a specially designed room for this to happen. Thanks for the review, though, I'll keep that in mind in future.
      I play trombone, loudest instrument on the face of the earth, lmao, we get 2 trombones and me on bass trombone in the band hall and we all together blaring as loud as possible can push damn near 120Db.
      ya, too technical....u dont go round measurin decibels at a gig...u soundcheck till it sounds right lol
      Geldof the Grey
      If you didn't understand any of that: 1. Turn on amp 2. Dial up 10 on every setting 3. Let the bassist, drummer and vocalist work out the rest
      OpeN WidE
      this should be up at the top of the articles. good work, yeah, a little bit of confusing stuff but it definately had its good spots.
      frigginjerk: coz last featured article and the article before it both were "guide to going live"... and yes, im agree that it's way too technical. all these dBs and stats are useless for the real life. though the article is very well written
      definately good, i would agree that it was a bit confusing but i get the main idea. good article.
      hey hey .. no it is important.. u wanna record a good bootleg , well it gets important. Nice article. i hope i get to implement what i've learned here. Thanks! and keep up the good work
      Backup Guitar
      Aww, I'm too technical for real life. I have reached the ultimate nerd position! Hoo hah. Thanks for all the feedback. I do appreciate it, really.
      good acticle backup a lot more technical than the others but very useful ive been wondering why my amp sounds quiet: its only 15watts
      Ax Man
      Altho I love the sound of a tube amp...I would never use one on stage. With a soild state amp you keep your setting the same, with tubes you have to keep changing things to keep that sound that you want, 'cause the tubes start to die (that's why they made the soild state amps) not to talk about other down falls of soild state vs. tube. Backup Guitar: Over all your article was good, but I've seen that most of the players here are young and don't understand the "tech" end of a lot of things. Oh ya, this will come with time, but maybe next time you "dummy" down things a little bit. Also placement of the mic on your amp is as importent as anything, location is everything. **FYI** You should put your mic on the crown of the speaker this will give you a true sound of your guitar or what ever your playin'. Altho the best way is to run a direct line out to the board (PA system). Just a general note: When you are mic-ed on stage you don't need to "blow and go" let the PA system do the work, that's where a good sound tech comes into play. Just a general note...0dB is when you can hear the blood run threw your ears.
      I'm horribly dissapointed that he didn't divulge the perceived volume differences between solid state and tube amplifiers. That's a huge importance right there. Other than that, a very good article. If you don't understand it, read it through again. Repeat and ask questions until you do. I'm sick and tired of going to local gigs and having the sound so God awful that I have to leave early. After I paid good money for a show.
      Why does everyone think the louder the better, shouldnt you just go with what sounds the best. And dont just say louder is the best cos it isnt.