Live performance levels

Posted: Thu Mar 23, 2006 12:39 am

Hi guys,

I’m taking a survey. I am trying to get a handle on what average and max SPLs are in the real world. Hope you can help.

What are the highest levels you all have measured for average SPL and max SPL in the middle of a live audience for the following performances?

Heavy Metal
Hip-Hop
Rock
Country & Western
Classical
Choral
Zazz
Blue Grass
Folk
New Age

What instrument did you use to take measurements?

Did you use weighing?

Any help at all is appreciated.

BTW, if I put this in the wrong place, please direct me to the right forum.

Thanks

Posted: Thu Mar 23, 2006 1:24 am

Screw decibel levels! If it hurts, it's too loud. If your chest is vibrating, it's too loud. If your friends can't hear you screaming at them, it's too loud. If you value your hearing, stay in the control room.

Hiding in the microphone closet
Ms. Remy Ann David

Posted: Thu Mar 23, 2006 4:50 am

aborza wrote:

What are the highest levels you all have measured for average SPL and max SPL in the middle of a live audience for the following performances?

I am afraid that my microphones are never anywhere near the "middle" of any live audience, they are much closer to the talent. Also one would need to measure many samples to get meaningful statistical information about average levels.

What are you trying to achieve with this survey?

Posted: Thu Mar 23, 2006 8:00 am

I am trying to determine what the actual average and peak levels are that an audience is exposed to for different live program materials.

This info is necessary to determing the hearing damage risk of the audience from different program materials.

This info is also necessary if one wants to prepare to record and play back an audio event at realistic live levels. That cannot be done unless you know what the audience experienced average and max true peak SPL was/is.

What little info I have found so far is spotty and highly variable. So, I chose this survey to collect as many samples as possible to try to get enough data to create a meaningful profile. But from what I have been able to find so far, it seems like no one knows or cares.

Posted: Thu Mar 23, 2006 9:35 am

Hi Aborza! Welcome to RO!

I don't know that you're going to find much info regarding your question here, as most of us never run our SPL meters out into the audience during concerts.

The information should be freely available though at OSHA's website. They do research this kind of thing and have made their findings public.

FWIW, I have measured (at the microphone position) a classical performance that crested the 120dB mark! Of course, using common sense and the inverse square law, we could determine that the audience was not experiencing that level at all. (BTW - it was the 4th Movement of Tchaikovsky's 4th Symphony).

J.

Posted: Thu Mar 23, 2006 12:55 pm

You have a very good point there. If you guys measure at the microphone, why not get the data from a central mic point? The inverse square calculations are simple enough.

But is there a central mic point that is representative? And how far would that central point be from the sound source so that I can start using the inverse square calculations? Hmm.

If you can suggest a smart way to ask the question, I will do so.

In the mean time I will visit OSHA.

BTW, Tchaikovsky's 4th Symphony, one of my favorites!

Thanks

ab

Posted: Thu Mar 23, 2006 3:28 pm

The inverse square law decay of sound is only relevant in the free field and for a point source, OK if you are in the middle of a footy field with one instrument. In a concert hall the decay is much less than inverse square due to the huge amount of reflected sound and the many sources. All too much of a simplification I'm afraid.

Posted: Thu Mar 23, 2006 3:53 pm

RemyRAD wrote:

Screw decibel levels! If it hurts, it's too loud. If your chest is vibrating, it's too loud. If your friends can't hear you screaming at them, it's too loud. If you value your hearing, stay in the control room.

Hiding in the microphone closet
Ms. Remy Ann David

We took our 11 year old daughter to see The Lion King [Broadway version] and it was all of the above.

A good show.. but it hurt.

Posted: Thu Mar 23, 2006 7:36 pm

bap, I'm sorry to hear that you were sorry to hear the results of a couple of moron sound guys that must have believed it was important to blow people out of their seats for a children's show. Shame on them. I find excessive sound levels quite annoying myself. Another reason why I remain in the control room for most live concerts.

Sitting on my butt and turning down the volume
Ms. Remy Ann David

Posted: Fri Mar 24, 2006 1:38 am

Dang; I'm with Remy on this one! Thumbs Up

And I'm NOT being an old curmudgeon about live shows, either. Most of them are just too damn loud anymore, and sound horrible. (Just because you CAN doesn't mean you should.)

If you read the trade mags, you'd think all was rosy in the live sound world these days. Unless it's outdoors, most live indoor shows I've seen are just awful. I make it a point to bring those soft "Hearo" style earplugs to at least get the decibels down 10-20 db to a comfortable level. (It's amazing how DIFFERENT it all sounds when the screaming and house reverb is reduced and you can HEAR the band really playing...hehe.)

But getting back to the question about safe hearing levels; I'd suggest you team up with an audiologist and take some levels at various points in the venue(s) in question. Even with good test gear, you'll probably find it's all over the road, and I doubt anyone here can give you any kind of definitive list, other than to "Stay away". (We're not kidding, really!)

Depending on the genre, the parameters of the hall, the number of people IN the hall (and what they're wearing - summer attire vs. heavy winter clothing - really), size of the sound system, the mood of the FOH engineer (really!) and whether or not the act in question is the headliner or the opening act. It all changes, right down to what seat you're in. (Hint: it's generally too loud anyway).

Then you've got Flown vs. ground stacks of systems, subwoofers vs. mid cabinets, and on and on. I wouldn't risk exposure at any kind of loud event nowadays, my hearing is just too precious, and I intend to keep what I've got for as long as I've got. The earplugs are part of my travel kit, and I'd never go into a live show without them; not if I'm forced to be in the audience, anyway.

It's easy to be "Bad" loud. These days, just about anything can be sampled, mic'd, amplified, crunched to an ear splitting roar with no letup. The CD loudness wars are very parallel to what's happening with live sound nowadays.

Then there's loudness as a result of good dynamics, REAL musical peaks and enthusiastic players who know when to play soft and when to hit it; that's what I want to hear, not over-comp'd chain saws.

My own internal alarm clock for "too loud" occurs when I feel my heart rate begin to change due to the thump of the subwoofers moving the air in and out of my lungs, or watching my pantlegs flap in the 50 MPH breeze generated by the subs. Noooo thanks.

Posted: Fri Mar 24, 2006 7:31 am

I agree with everything that JoeH said.

I would only add that I worked at a college as a professional audio engineer and did have access to an SPL meter. Taking readings on various concerts I found that what I was measuring depended on a lot of factors that no clear "norm" could be stated for each type of music. The loudest concert I attended while working for the college was by the band Phish. I had soft foam ear protectors and external headphone type hearing protectors and it was still too loud.(The concert pegged my General Radio sound level meter on the highest scale) The softest concert had to be a performance of "Morton Feldman's, The King of Denmark (1964)" which is a percussion piece played with fingers and other body parts. I could not even get the SPL meter to register other than the back ground noise.

I don't think you will be able to quantify by genre what each type of music will register on a SPL meter.

Posted: Fri Mar 24, 2006 8:26 am

When setting up for a live gig, I will always use a hand held SPL meter, set to slow on C weighting and tune 0dbu to 85db spl in centre house position. Once I've done that, I then walk around all areas of the venue to see where the peaks and troughs are. I'm always using subs (that are set to a level that most would consider conservative) so the pink noise is not filtered. All this is done whilst wearing ear plugs.

I then base my mix on the average level set during tuning of the system and during sound check/rehearsal it's at a comfortable level. From then on, once the audience is in, I generally go by ear, knowing what 85db spl feels like in the venue, and adjust accordingly for the absorption factor of the audience. I will also always have the spl meter on at the mix position an will turn it down if I start reading over 85db spl, as it's probably 90 odd in centre house.

As a side note, I was recently doing a show at the Sydney Opera House and John Fogerty was in the Concert Hall upstairs. We could quite clearly hear the kit and bass. I was told that it was 119db spl at the mix position! Insane.

Posted: Fri Mar 24, 2006 11:03 am

Wow; it's interesting you mentioned John Fogerty and loudness... a couple of stories here regarding John...

I saw Creedence wayyyyy back in 1969 at the Spectrum in Philadelphia, and at the time they were riding high on the charts as well as gaining the new reputation of being one of the loudest bands on earth (at the time.) To be fair, all they had was a better sound system than most (at the time) - a bunch of "Voice of the Theater" cabinets and power amps strung together by a maverick sound company. To my young ears, they sounded great - clear, crisp sound. We'd never heard anything like this before. (Saw Zappa in the same venue next year after that, same thing.)

Many years later, in 1986, I happened to catch John in his first solo outing in support of the "Centerfield" LP. At mid-center first section in the house, (an outdoor venue here - the Mann Music Center) the bass was so overpowering and nauseating that I went to the FOH guy after the show and (nicely) complained. Most of the show, Fogerty's vocal was lost, too.

He told me that all the sound I was hearing was coming off the stage, from the bass player's amp ITSELF, and that he wasn't even bothering to run any low end through the house system. (Which I still find hard to believe to this day.) Weird side note: I'm actually quoted in a book by Hank Bordowitz about this show, called "Bad Moon Rising" the unofficial CCR history. Go figure....

About twelve years after that, I went to see him again (you'd think I'd learn, eh? Haha) at the Tower Theater in Philadelphia around 1998. To be honest, the sound was great in general, but still overpowering for an indoor event. We're talking subs to die for plus what was then becoming a trend: Trapezoid boxes in horizontal arrays with better dispersion, higher SPL, etc. (Lucky us! Rolling Eyes

) I had forgotten my "hearos" plugs at the time, and good god, it was excruciating. I was honestly worried that I was doing some damage; I am blessed (or cursed) with some kind of physical pain that begins to happen in my left ear as soon as the spls go up, and this one was really really painful. I spent most of the show with a finger closing over my left ear canal.

Never again; I don't go anywhere like that - any live event - without a set in my car as well as my pocket. I don't blame JCF himself, it's pretty much everywhere. He wasn't any worse or better than other live shows. They're all pretty much too loud.

Posted: Mon Mar 27, 2006 11:36 am

DavidSpearritt wrote:

The inverse square law decay of sound is only relevant in the free field and for a point source, OK if you are in the middle of a footy field with one instrument. In a concert hall the decay is much less than inverse square due to the huge amount of reflected sound and the many sources. All too much of a simplification I'm afraid.

It's still applicable. Though, agreed, it won't be 100% accurate due to sound from reflected surfaces. It should still be accurate enough to make a well-informed, educated guess.

J

Posted: Mon Mar 27, 2006 3:04 pm

Cucco wrote:

DavidSpearritt wrote:

The inverse square law decay of sound is only relevant in the free field and for a point source, OK if you are in the middle of a footy field with one instrument. In a concert hall the decay is much less than inverse square due to the huge amount of reflected sound and the many sources. All too much of a simplification I'm afraid.

It's still applicable. Though, agreed, it won't be 100% accurate due to sound from reflected surfaces. It should still be accurate enough to make a well-informed, educated guess.

J

No, its well off being useful. Once you hit the reverb radius or critical distance, the sound level doesn't drop much at all with distance ie. it is uniform around the hall (diffuse). The critical distance is about where we put our mics, most of the audience are in the reverb wash, this is by design and the design is to counter the inverse square law, so that all the audience get the same sound pressure level.

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