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live pa setup question

Discussion in 'Recording' started by InsaneGenius, Aug 17, 2011.

  1. InsaneGenius

    InsaneGenius Active Member

    I am trying to set up a pa system with a mixer, eq, compressor, and amp. When I go in and set up the eq and all with just me and a friend in the hall. The sound is bang on. But later, when 100 people show up the sound is horrible. (sounds tinny) Any ideas on how to set this up before hand to counter the 100 people in the room? How do the pro's do it?
    Thanks.
    Btw I am used to home recording, but not live setup..
    I have a spectrograph on my computer to run though.
     
  2. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    Have some recorded music you are familiar with going when people are arriving. Unobtrusively set the eq before your set with people in the room.
     
  3. dvdhawk

    dvdhawk Well-Known Member

    Your PA system may just be under-gunned too. Can you provide any details on the PA? (amps / speaker configuration etc.)
     
  4. Kapt.Krunch

    Kapt.Krunch Well-Known Member

    As well as, what are you running through it? Just vocals? Or, everything? Are you trying to punch kick drum and bass guitar through pole-mounted full-range speakers? By your omission of any mention of crossover/subs, we can only guess that whatever you are running through is going to, possibly, a pair of speakers? It makes a difference on how to answer your question.

    The people in the room are absorbing sound...and, possibly, reflections. You need to compensate for that, compared to an empty room. The solution may involve speaker placement, instrument levels, overall power level and EQ tweaks. Even something as mundane as temperature and humidity changes can affect the sound from then to now, but it's best to narrow down the obvious, first.

    As dvdhawk requested, provide brand/model numbers of all the PA equipment, connection configuration, what you are running through it, and a guesstimate of room size and shape? You'll get more-informed responses.

    Kapt.Krunch
     
  5. Unregistered

    Unregistered Guest

    ... [double post]
     
  6. InsaneGenius

    InsaneGenius Active Member

    Hey, I just wanted to say thanks guys. I set up the system and everything went good. I was so confused the last time I set up a system because the sound was tinny and bad when people were in the room. However, I now find out someone was messing all the settings up. This time we took pictures of the settings after set up, and guess what? Someone again totally screwed them up. Since we had the pictures we reset to our original settings and the sound was good. It was just as you said, the bass was a little on the high side. We cut that back and the sound was great. For anyone in the future reading this thread, this is what we did.

    1. We did use white noise and a spectrogram. From there we set the main eq so the spectrogram read flat levels across all frequencies. (That eq was then left alone, it is only used to fix room)
    2. We set all gains for all mics to clipping at about 70-80 db vocal level. Then backed off 5-10%
    3. We then raised each eq on the mixer for each mic, until we heard feedback. (highs, lows, mids) Then again backed it off a bit. We then had all the levels set and now could eq to taste.
    4. From there we did volume and eq settings to make all mics sound the same.
    5. Next we set the compressor/limitor/gate unit. Gate, = just enough to remove system noise. Compressor = just taking off the very top at a moderate level 4:1 ratio, fast attack , and 0.5 release. Limiter = Just to the point of seeing it activate, so we don't blow up the amp.
    -- this was the setup, then on the day of the show, we only had to remove the low end and boost the amp a couple db. And it sounded great!

    Thanks guys. Please add anything that I missed.
     
  7. AUD10

    AUD10 Active Member

  8. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    Such a measurement doesn't provide enough information for setting main system eq in any meaningful way. There are all kinds of reflections that will create constructive and destructive interference, and that will change dramatically from place to place in the room. In other words you can't "fix the room". It is possible to use analysis tools to compensate, but it takes more time and expertise than I think you have. The practical approach is to play recordings you are familiar with and eq by ear.

    Using the spectrograph to pinpoint feedback in the monitors might be a useful application.
     
  9. MadMax

    MadMax Well-Known Member

    <quote>Such a measurement doesn't provide enough information for setting main system eq in any meaningful way. There are all kinds of reflections that will create constructive and destructive interference, and that will change dramatically from place to place in the room. In other words you can't "fix the room". It is possible to use analysis tools to compensate, but it takes more time and expertise than I think you have. The practical approach is to play recordings you are familiar with and eq by ear.</quote>

    Uhhhh... whatever... You wouldn't last on the crews I've worked with. Flyin' by the seat of your pants usually gets you your last gig.

    The right tool used in the right way does allow setting systems up quite adequately... Sure, you have to tweak as the venue fills, but waaaa... That's reality.

    Anytime I get in a new room, I always try to allow enough time to "pink" the room. Not that I have to use a tool, but the reality is that an RTA will not be confused if I have a cold, headache, fatigue, etc. It's going to be far quicker to point out a problem that I may not hear.

    I locate the most expensive seats in the house and the worst seats in the house (practically speaking)... I'll RTA and EQ for the best compromise between the two and let that be my starting point. I then note what I'm getting off the analyzer at the FOH position. Next, I bring up music that is similar to what I'm gonna be mixin' to see what I'm getting at FOH. During soundcheck, I note what I'm getting and cruise the venue to see if there's anything wonk and usually only hafta' make minor adjustments. I then monitor the RTA throughout the gig, usually only making tiny to minor changes to the house EQ.

    This works outdoors, in 50 seat clubs, 500 seat theaters and 15,000 seat arena's I've worked in.
     
  10. audiokid

    audiokid Staff

    FWIW, this post along with dvdhawks is spot on. I did live sound for two decades. I used a RTA in the early days but found it pretty useless in the big picture. Once my ears got tuned in and I could tell what freq were standing out, I tossed that and never looked back. I love tools but the greatest gift in recording came from teaching myself what freq I want by listening and experimenting in live sound.

    The number one thing I found that makes it all come together is serious power matched with stellar speakers followed by a killer crossover, console with exceptional headroom and then your 1/3 octave graphs.
    If all the above is great, and you know how to use it, you don't need to be messing all over the place, confused over what is going on.
    It all flows so much better if you rig is excellent. (note: if your sound sucks, your reputation of the band will too) If your sound is excellent, opportunities grow in all directions).

    When the room fills up, that's when you go to work. Ping as go and you will get to a point where you'll have it nailed down in a few minutes. Then, as the room heats up, you tweak. I often walk the room to see if I should compromise. I also got to a point where I only played rooms that sound good. Bad rooms make you look bad. Its a two way road. Most rooms however, can be concord so you at least always sound better than most bands.

    There is more to it than this but this is the basics.
     
  11. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    I certainly wouldn't stay on any crew with you on it.

    Regarding the wrong tool for the job, an RTA is it. The right tool would be something like SMAART, TEF, SIM etc. because, in contrast to an RTA, they are not time blind and can to some degree differentiate between the direct path (what the speakers are doing) and the indirect paths (what the room is doing). And that's completely beside the point since whatever tool you use the most important factor is the user's knowledge and experience. Given that the OP hasn't shown he has the required skills yet the best option for them is to listen to some recordings they know well and adjust by ear. What I suggested to them in no way defines what I do when I set up a system.
     
  12. dvdhawk

    dvdhawk Well-Known Member

    Love it, stale thread - fresh fireworks.

    boulder you seem like a reasonable and intelligent guy. And I'm not in any way disparaging your skills, or your system - but I'm pretty sure Max could turn on his arena line array and knock your system over. So all I'm saying is you're takin' a leak in pretty tall grass here.

    Carry on...
     
  13. audiokid

    audiokid Staff

    Must be the Sept air and all the pressures of our global state getting everyone on edge. Please please, lets all breath for a while on this one and if you want, come over and roast my ass at the Neos thread.
     
  14. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    My system is a bunch of random stuff I cobbled together on a shoestring budget. All the better when those doubtful looks at load in evaporate by the end of sound check and become big smiles in the first set.

    Someone using 1980s tools in the 2010s to tune their line arrays gets my respect if he gets results. He must have many years of experience to overcome the inherent limitations of RTA. Does the OP also have that experience? Not as far as I can tell. Will he know if the measurement mic is, for example, in a null at 63Hz? No. He will boost that frequency 12dB and burn some voice coils or push them right out of the gap or merely end up with a rumbling mess trying to flatten the curve. I was just trying to save the OP a bit of trouble.
     
  15. Unregistered

    Unregistered Guest

    Walk into a supermarket and sing. Now do the same in a carpet shop.

    Not only could this get you arrested but there will be a difference in the sound. This is the analogy of an empty vs full venue. The professionals and in fact, neither can any wiz software guess what something will sound like when filled with moving humans. It's akin to setting your home audio eq settings before moving all the furniture around. I've spent many a gig unable to hear the vocalist or having my spleen bounced around by an overdriven bass by a band who want to be 'professional' without having a 'pair of ears' in the crowd to listen to what's being put out.

    Sound is subjective, not objective and the main reason why audio quality is in the decline. Try bringing along someone who is willing to stand out in the crowd and signal to you that you have too much of this or not enough of that instead of trying to second guess the mass of an audience before they turn up. And remember, if you're not very good, half of your calculations and tweaks might just disappear off to the bar leaving you with forty cubic meters of empty space to fill.

    Good luck with the band

    MS
     
  16. MadMax

    MadMax Well-Known Member

    Whether you use SMAART, TEF or any number of OTHER RTA's, (That IS one of their primary functions) you have to use the brain you have in combination with the tools, your ears and your feet to know what's going on with PA/room interaction. Whether you're pushing faders on cobbled together speakers on sticks or an 80 box line array, an external tool is essential to get your bearings in an unfamiliar environment. And

    I guess when starting out, it's not common sense to get your butt out from behind the console and go listen around the room to what's actually happening... but that's what you have got to do. Granted, you might no be able to get to every corner and all the good seats once the place is filled with punters, but it's certainly not impossible to get around enough to listen to what's happening and make rational decision based upon what you're hearing.
     
  17. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    Yep, whatever measurement tool you use (ears, RTA, FFT) you have to measure in different places and interpret, and that's where experience comes in.
     
  18. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    So, what I'm getting is that you should play badly so people don't hang around and mess up the eq settings you made in the empty room.
     
  19. Unregistered

    Unregistered Guest

    Erm ... yes.

    MS
     
  20. bouldersound

    bouldersound Real guitars are for old people. Well-Known Member

    Hilarious.
     
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