SPL for live shows?

Posted: Tue Sep 25, 2007 1:40 pm

I've been drafted to do the sound for a few live gigs of a band I've been working with in the studio. I have nearly no experience or training with live sound.

I've got a few questions to that extent.

1. What SPL should I be aiming at? I know that 97dB is safe for 30 minutes at a time, which is the approximate legnth of a set they're doing.

2. How feasable is keeping the SPLs down to 85-97 dB in a live set?

Also, what weighting should be used for a Radio Shack SPL meter? C or A?

Posted: Tue Sep 25, 2007 2:38 pm

When I'm at a concert, or i do one my self, the SPL is close to the pain thresshold Razz

Well. i TRIE to keep et a few notches down when I'm stearing the sound, but you know. Can't stop Rock 'n Roll.

Posted: Tue Sep 25, 2007 4:20 pm

Try to keep the SPL from exceeding 94 dB. The 'A' weighting is most sensitive above 500 Hz., the 'C' is more uniform, full range. For music, use the 'C'. Unless you have to show it to a cop, then use the 'A'... Laughing

Posted: Tue Sep 25, 2007 5:15 pm

110dB. I know because I've stood behind the mix engineer for John Legend, Mudvayne, Mnemic, and Katatonia. You mention "sound reinforcement" and they tend to love you and invite you into their cordoned area, rather than saying "yeah I like to do live sound" in which they just stare at you with a retarted look

Posted: Wed Sep 26, 2007 4:03 pm

It will depend on the venue, stage noise level and the audience age. Older people a few db less than 94. They will kiss your feet if you can get 85dB. Use your ears and only set it as loud as it needs to be not as loud as it can be and everything should be fine. You will have to find the level that overcomes the stage levels and that will pretty much set how low your volume can be(if everything is run through the sound reenforcement system).

Posted: Thu Sep 27, 2007 1:49 am

110 dB ?!?!? That's a friggin' power saw! I've been to a John Legend concert, it was no 110 dB...now, maybe those others. There are too many live sound mixers who've been over-exposed to their own too-loud mixes and are now practically numb to their own demise. They have no business sitting behind a board, IMHO. If I EVER meet up with the SOB who mixed Van Halen in the late 90s, I'll shoot him. It was painfully bad sound.
Anyway, get a Radio Shack SPL meter and learn to use it. I use mine at various points in the audience area. Then you should go to H.E.A.R. and read up on hearing exposure and damage. If you are wanting to stay employed in the recording business, you definitely need to use hearing protection EVERY live gig you do. That includes any rock concerts that you attend. Also, do a search here for "osha" under Mixing Live Sound.
Zemlin posted this question last year and someone posted some OSHA regulations at the end of the thread. 110 dB is for a mere 0.5 hour...

Posted: Sat Oct 20, 2007 10:22 pm

You guys throwing around decibels like that freak me out. You can't say "This show needs to be X dB." That's absurd. There is no standard for measuring given...what distance, what noise?

There are too many variables. I worked in a structure that had ambient room noise over 75dB from the HVAC system alone. Outdoors is different than indoors. Live rooms and dead rooms effect the levels and intelligibility.

Do what suits the genre of music, the vibe, the crowd, the ambient noise, the local SPL ordinances, etc.

OSHA's recommendations are a bit bogus. They are exposure ratings FOR THE DAY (8 hour period). You have no way to know what the crowd has done to manage their exposure time to loud noise throughout the day. OSHA's recommendations are not for music either. Working in a manufacturing environment where a noise maintains pitch for extended periods of time is much harder on the ears and brain than music. OSHA's recommendation are for exposure before damage to the hearing threshold. That does not mean that music should be at the OSHA levels all of the time either. There is no reason to hurt people.

I also think it is stupid to spend 150k on a Midas or Venue, all the front end gear that I use, and secure the best sounding speaker systems, and cause people to use earplugs. How stupid. They don't get the fidelity. We might as well stack a bunch of Cerwin Vega crap up there and blow if we are going to do that.

Posted: Sun Oct 21, 2007 7:36 am

If it's in a club I always have 3 setting. Because of the changing amount of people in the club. Most of the times the first set is the people coming in, the second filled and the third people going home.

You need to find a preset for 2-3 different situations.

It should be as loud as the music style dictates. I've done all kinds of music and each one has it's nuances.

African and Latin music has to be loud for the percussion but not annoyingly loud.

Metal and Glam/Big hair rock has to be loud, thats the way they like the music, loud or louder. If you don't have it really loud the music looses it's effect, which is to numb you and make you deaf and stupid.

Rock itself has to be loud but just below the too loud threshold.

Blues depends on what type. Folk, well clean and warm and just above people being able to speak normally.

So throw out the Db meter and use your ears and brain.

How sophisticated is the sound systems?

How many monitor zones?

Are you the front system engineer with others to do monitors?

Do you have EQ? Do you have parametric EQ, feedback destroyers, just tops with no subs? All active, are there compressors on the system?

You know how the recordings sound, go to one of there rehearsals to get an idea of what they sound like and make it bigger and better. I would always try to go to a rehearsal of the band I was working with to find out what is what and who you have to watch out for.

Like who sings off on their harmonies, you have to listen and if they are off you bury the fader, when they are on you can blend him/her in. Things like that.

If you don't know the system call them and stop by the place and take a look. Believe me you will be horrified and have to show up many hours early to get it to work right, usually house systems are a mess!!!!!!

Posted: Sun Oct 21, 2007 6:10 pm

I'm a great fan of clarity as well as tone. With these two things in control, you can generally push the volume to a great 'feel' point which goes very far into peoples enjoyment levels. Amplifying poorly structured frequencies and noise is just crap. LOUD crap. And no matter what style, who wants to spend their money listening to unlistenable crap simply because the system sucks.
A LOT of house systems are simply the best money deal the venue could swing without regards to quality and sound design for the room. Most have skewed crossover points and cabinets that arent designed for the shape and size of the room. Most are too long in their throw and most do not match the highs coverage with the lows. So a visiting soundguy has to fight uphill from the beginning in getting a system to behave and sound good. Whats even worse is having the house engineer there....mostly guys who have listened to far far too many loud dates and cant hear much anyway. Plus they freak when you bring the system into focus witha few minor moves of the processing and the gain staging.

Thats why I dont do live any more.

Posted: Mon Oct 22, 2007 7:27 am

I certainly stay away from doing club sound due to all of the above. And, yes, clean sound can minimize listeners' fatigue. But I still watch the SPL meter. It is too easy to let the 'feel factor' sneak up and bite you on the ass after a long exposure period.
The other night I attended a concert a concert by a Scottish band that a longtime friend was providing the sound for. Acoustic guitars, violin, bouzouki, and...pipes. As in BAGpipes. Blasting into an SM57. Here we were in a nice, 500-seat auditorium, with Meyer MSL-3s (4). Without the pipes, the detail was great, the stringed instruments were crisp without shrillness, the vocals clear and defined without any harshness. Then the pipes would come into play. Because the band members were half-deaf from over-exposure to these things over the years, they demanded the pipes be mixed into their wedges at a level that caused the stage-spill to be too loud in the house, even with NO pipes mixed into the house system!
I had to leave halfway through the show, my ears were ringing...

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