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Understanding a PA system

Discussion in 'Live Sound [BG]' started by tgriley62, Dec 21, 2016.

  1. tgriley62


    Jan 25, 2011
    S.E. Mo
    Looking to get a basic PA. I am on a budget so powered speakers are out so if using an unpowered mixer would this be the best way to power it. Use a two channel power amp to run one 8 ohm main & 8 ohm sub on one channel & another 8 ohm main & 8 ohm sub on the other channel. Use a second two channel power amp to run two 8 ohm monitors on one channel & two 8 ohm monitors on the other channel. To me this seems like a simple way to power a PA but, is there an easier way without using powered speakers

  2. before you shoot yourself in the foot - what is your budget - realistically
    DirtDog likes this.
  3. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    This first.

    Also, it would probably be best to have a crossover and power the tops with one amp (or one side of and amp) and subs with another. Yes, the speakers will likely have internal crossovers. But if they....cross over....each other, it can get muddy. In other words, if the bottom frequency of the tops goes below the top frequency of the sub, they could disagree with each other.
    Plucky The Bassist likes this.
  4. DirtDog


    Jun 7, 2002
    The Deep North
    Before budget, figure out your requirements. Channel count, preamp requirements, DSP processing, power, coverage, SPLs, sounds quality, applications (vox only, vox, guitars and drums?)...

    Then see if your budget meets your requirements' expectations. If not, adjust budget or expectations.
    oerk and Frankjohnson like this.
  5. buldog5151bass

    buldog5151bass Kibble, milkbones, and P Basses. And redheads.

    Oct 22, 2003
    Is this just for vocals, or kick drum, keys, or what? How big places are you playing?
    Slough Feg Bass likes this.
  6. two fingers

    two fingers Opinionated blowhard. But not mad about it. Gold Supporting Member

    Feb 7, 2005
    Eastern NC USA
    Yeah, the short version is that we need more details. :D
    And I likes this.
  7. lz4005


    Oct 22, 2013
    Not to mention you'll be better off being able to control the volume of the subs separately from the other speakers, even at the expense of being able to run a stereo mix.

    I don't know why OP thinks powered speakers are more expensive than power amps + cabs. It all pretty much evens out in the end, regardless of which box the amps are inside of.

    The best thing to do would be to concentrate on getting enough channels and monitor capabilities to start with, as much as you can afford, with no subs. Concentrate on good full-range speaker cabs. Then save for and add a powered sub later if you need it. Of course that depends on what you're wanting to run through it, as others have said.
  8. tgriley62


    Jan 25, 2011
    S.E. Mo
    Thanks everyone. Right now we are a basic bar band classic rock/country 3 piece. Guitar/vocals, bass/vocals & drums. I know budget will depend on things such as new verses used and other things. I am just thinking of a basic PA set up for a typical bar with 100-200 people. So would a 10 channel mixer be enough and just two powered 12" mains plus one powered sub & then add on stuff as needed?
  9. lz4005


    Oct 22, 2013
    Nobody else can tell you how many channels you need for your band.
  10. buldog5151bass

    buldog5151bass Kibble, milkbones, and P Basses. And redheads.

    Oct 22, 2003
    Again, what is going into the PA?

    If you are on a budget, I would go powered mixer (or mixer and power amp) and passive cabs. Just as the fact that many bassists are getting class D heads and Neo cabs means there are a lot of bargains our there on used bass amps there are a good number of used PAs out there.

    If you are putting more than vocals into it, either good 12s or consider 15s.
  11. The more specific you can be about the upper limit of what you are willing to spend, will result in more useful information.

    'Basic' means different things to different people.
  12. tgriley62


    Jan 25, 2011
    S.E. Mo
    To be honest I don't know what we need to put through the PA. This is our setups. I use a Rumble 500 head & two 2x10 cabs. Guitarist just got a jet city 20w tube amp that I have not heard yet so I don't know about his volume . Drummer plays on the medium to hard side. My thought is just a vocals only PA with maybe kick drum
  13. buldog5151bass

    buldog5151bass Kibble, milkbones, and P Basses. And redheads.

    Oct 22, 2003
    Without knowing that, there is no way to know how many channels you will need.

    I would guess your minimum (planning for future expansion) would be:
    1-3 - vocals
    4-7 - drums
    8 - guitar
    9 - second guitar/keys
    10 - bass

    Again, if bar band is all this is going to be used for, consider going powered mixer, and get some used cabs - LOTS of good stuff out there cheap.
  14. JohnMCA72


    Feb 4, 2009
    Honestly, I wouldn't touch a powered mixer/passive speakers anymore at any price. There are just too many good powered speakers/unpowered mixers around. The flexibility you gain from powered speakers/unpowered mixers is a huqe plus.
    • If you need to add speakers, just add them - or replace them with more capable powered speakers. You can daisy-chain powered speakers indefinitely. Can't do that with passive speakers, not to mention that somebody with a heck of a lot more training than you or I has done all the proper power/impedance matching between the amps & drivers, & probably added some useful processing as well.
    • If you need to add input channels, auxes, effects, etc. get a new mixer & keep the speakers. You aren't stuck with power amps that are matched to your old speakers, while the new ones might not be a good match at all.
    What you need now may not be the same as what you need in 2 years, 5 years, etc. Flexibility gives you a chance to grow and adapt over time, as well as put together a system to handle a variety of rooms or bands. Many systems evolve over time, upgrading or adding components as needs evolve. I've got a system that's built out of passive mixers, powered speakers, plus various accessories, that can handle any job from 1 or 2 guys in a coffee shop up to a pretty large band with a thousand or so audience outdoors, and anything in between depending on what gear I happen to bring. It wasn't built all at once, but rather over several years, & having the plan to keep it flexible made that possible. If I'd started with a powered mixer/passive speakers, that gear would be just sitting in storage, waiting for somebody to unload it on so that I could put the money into something else.
  15. buldog5151bass

    buldog5151bass Kibble, milkbones, and P Basses. And redheads.

    Oct 22, 2003
    Agreed - it gives tons of more flexibility, but for a cheap option - you can get a decent used system for $500 that will handle and bar and take more than just vocals. For a bar band on a budget it's a good option, just like a young bassist can pick up a very good 4x10 cab and 250 watt or so head for under $500.
    moshspeggeti likes this.
  16. Let the drummer kick it like he means it and a simple vocals only PA will be all that's required.
    bassliner50 and Roxbororob like this.
  17. MakoMan


    Oct 17, 2011
    Ottawa, Canada
    We're a basic bar band classic rock/country 4 piece and what you describe above is almost exactly what we use... two powered 12" mains and a 10-channel mixer with one sub. Our mixer is a basic Soundcraft EFX8 that we use to run 3 vocals, two guitars, bass and the kick drum... we even have a channel left over. We can easily get by with one sub for most venues and if we need a second, we rent it. In some places we don't even need to mic the kick drum or bass so we can get by without a sub.
    Is it Modulusman sound? Uh no. But it sounds great for the venues we play and we get a lot of gigs. We also play quite a few fairs and festivals etc. where the PA is provided. We've talked about upgrading, but so far we just haven't needed to and for the few times we did want more we just filled out our system with some good rentals and build the price into our fee.
    It does all depend. Only you can figure out your real needs, but for my money what you describe is a pretty good basic PA system for a bar band.
    Last edited: Dec 22, 2016
  18. Medicine Man

    Medicine Man

    Apr 10, 2015
    I would sink most of the money into decent powered mains for a start as well. If you are running your own sound, the dsp in powered mains handle a bunch of technical issues for you. You can get by on a cheap board and monitors until you have more money, and I also wouldn't worry about the sub until you can afford it. Good mains make your vocals sound better which equates to more gigs.
    AndyLES likes this.

    MYLOWFREQ Supporting Member

    May 13, 2011
    New York
    I'd consider a minimum 16 ch mixer, two powered speakers, two powered wedges, a digital reverb and a delay unit. If you're on a budget, get them used. Then, I'd invest getting one or two 4 ch compressor unit(s). With these plus the amps, you'd be fine for what you're explaining. If you have anybody who's going to do sound for you, and if you have the time before a show, I' highly recommend two multiband graphic eq's to pink out the room before shows although that's not feasible in most cases.
  20. s0c9

    s0c9 Supporting Member

    Jan 9, 2014
    1964 Audio artist, Fractal Audio Beta Tester
    Well... there goes the budget PA !! :)

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