Discussion in 'Live Sound' started by multoc, Feb 20, 2007.
Remind me what curve I'm following and what exactly I'm adjusting to fix?
OK, Loc. Nobody has replied yet for a reason. And I do NOT mean to be a smart-ass, but this is the type of question where, if you need to ask it, you probably should NOT be the person doing this.
In general terms, you running an analysis of the sound system coupling with the room it's in. You are attempting to "smooth out" resonances and other accoustical artifacts that occur when the sound hits the rooms' physical boundaries and starts to bounce around. Then you can use JUDICIOUS use of a decent equalizer to minimize these artifacts (mainly feedback). It does NOT replace good mics/placement, well-designed loudspeakers, or a good soundperson at the board. And I have never "followed a curve" to attain that. That's for the DJ's to do
I was only asking because I was about to take a test for my Sound Reinforcement for Stage class, and I had a brain fart. Well you should be following a fletcher munson curve. Based on your knowledge of that by using a real time audio analyzer and pink noise you put a calibration microphone at various points in the venue and adjust using a 30+ band Equalizer. I remember now only because it all flooded back to me during the test.
OK. Good luck on your test!
Is there a reason to follow Fletcher-Munson rather than more modern equal loudness curves?
because fletcher munson tells you the points at which the human ear is most sensitive at a certain volume
For using pink noise to set up a room, have a look at this thread: (Dead Link Removed)
Good point, Bos.
If the F-M curve states, in laymen's terms, that the human ear is less sensitive at the LF and HF extremes, dictated by the SPL, I am expected to EQ to compensate for that? I understand that at lower volumes, the sensitivity to those extremes is less, so I BOOST the low end on the EQ?
In live stage sound, no...that's where the garbage is. This post was presented to the live sound community, not to the studio people ( I have tried being both, I must suffer from ADD :lol: ). If I was doing RTA of a CR or studio, things might be a bit different. I may WANT to hear 30-40Hz at a decent level to scrutinize the material. If I want that in live sound, it's directed to the subs, via busing the kick, bass guitar, etc. to that portion of the system. NOT by EQ'ing it, which will introduce all the BAD artifacts live sound has to deal with (rumble, wind noise, pop blasts, foot-stomping, etc). And, by the same token, I realize that I need to watch the other extreme to minimize listeners' fatigue and to protect the system from HF artifacts. That's why I made reference to the "DJ curve"-THEY like to boost the 2 extremes with the "smile curve" on the EQ...
The equipment and the room are linear with amplitude and don't have F-M curves, so you RTA for flat. For studio monitoring work, you listen at reference levels to maintain consistency between mixes. For live sound, you adjust the overall volume for "correct" level in the venue. In either case, you can then adjust the EQ to correct for deficiencies in the source material. In neither case should you use "loudness" correction (derived from F-M), except for the special case of testing a mix (or master) for how it sounds in a variety of reproduction environments.
Like the below-stage scene in APHC with Rusty and Lefty?
Fletcher-Munson did the first measurements of this (1930's?) There are more recent measurements that are thought to be better, but maybe people use the term F-M generically. I haven't read about this in a while.
Update: Here"s Wiki
Who told you to go by the FM curves? That is a good guess at how people used to hear when those tests were made. New tests are revealing new curves. Truthfully, the changes are slight, but changes none-the-less.
Now, we know that the ear hears most linearly at 85dB. Fact. We also know that we do not like to listen to music the way that we are most sensitive to sound. We like 6 to 10 times the bass and more highs as well. We generally do not like 500Hz. So the room will come into play, true, but the loudness of the PA is going to effect the curve, because our ears do not maintain linearity above 85dB, and most concerts within city limits will be 100-110dB on average. So, who is to say that you WANT it flat that loud? Your ears cannot take the top end at those volumes.
If your school is not teaching you to use a high frequency shelf, rounding off the highs gently from about 6kHz on up, then they are morons. If they are teaching upi to make a system ruler flat at any volume other than 85dB, then they are morons. Get your money back and read some books. If you run sound like that on a big dog system, the system tech will take you out and have you beaten, or hang out backstage by the drive rack during the show. You'll never hear that they are rolling back the gain on the amps because your ears will be too fried to tell.
I don't remember anymore if they told me to go by FM but basically my teacher ran sound for touring broadway shows for 8 years so he knows his $*^t. But i haven't had this class in forever due to weather and mid-winter breaks! lol but i passed the test which had no questions on pinking
Your teacher may or may not know his stuff. Don't ever assume that working in a specific location, field, etc for any amount of time means that the person is knowledgable. There are major engineers that have always been analog guys, that haven't a clue about digital, and vommit all kinds of misconceptions in their trade rag columns. There are guys that know what works for them in specific applications, and operate correctly, not understanding why things are the way that they are. Behringer has making gear over 20 years, but that doesn't mean that they know audio. Get it?
What you should do is look at balancing the PA first without EQ. EQ should be your last resort. You might be able to make the system adapt to your room by moving the speakers or power fading. You should also let the curves match the music. A classical setting will be voiced much differently from a rock setting.
I am sure you know about this, but you could take a SIA Smaart class at an NSCA show, or find a rep near you. Smaart isn't perfect, but it is a good common tool to use for system voicing.
by the way to defend my teacher he obviously does know his stuff as I had to watch video from him being a production designer/FOH for a massive detroit electronic music festival where there were 5 stages with massive speaker arrays. It was very nice and he's done it since 2002 so he knows his stuff
His name is Everett Armstrong apparently he had some industry story he was involved in where a production company in florida took a crap load of lights for one year of this festival and the company hadn't given the ok but somehow these workers got the paperwork so they got suspended setences.....i don't know the company in florida but it's an acronym it starts with an M
btw this is our book
Title Live Sound Reinforcement Plus CD
Author: Stark, Scott Hunter Publisher: MixBooks
ISBN: 1592006914 Edition: 1st (Dec, 2004)
for Class: Required Paperback: Y
Nice book. Does it fit into your back pocket when you go to gigs?
Multoc, you have a LOT to learn....I've been doing live and recorded sound for ove 30 years and I have lots to learn. The day I don't, I'm outta here.
Stop talking down to the people on this site. You've been doing that on several posts here, and you are a beginner, painfully obvious at that. You can read all the books you want (and should), but it's the real day-to-day hands-on experiences that ultimately will shape, and test, you.
As far as Broadway sound mixers go, that's a big gig. Lots of wireless, lots of orchestra. But there's the one I saw who, when confronted with a 100-watt Marshall stack coming at him like a 120-dB
locomotive, freaked and ran away from the board.
It was my brother-in-law, and the dumbass had all the schooling in the world (NYIAR), but had almost nothing in terms of "real-life" experiences with bad acoustical environments, amateur talent that couldn't work a mic, intermittent connections, or, God forbid, narcissistic guitar players.
BTW, MY production company is based in Florida, has an acronym for a name starting with the letter 'M'....I'm no crook. There's too much work in this entertainment-driven state for the earnest to have to resort to working up there...
CAlm yourself mr. moonbaby I'm not talking down to anyone I'm just defending the guy that's all. I'll have to get a website or something from him. Anyway as far as live sound goes yeah I'm a real beginner I won't deny that but I also know how to make something sound decent I have mixed my own bands stage sound to great success and have helped out with large FOH gig's, I assisted and got great advice from John Legend's G-mann when they were in detroit so I'm getting into the game, so don't jump to conclusions I was just asking a quick question on here and this topic blew up!
Your defense shows you didn't hear what I said. That's ok.
Separate names with a comma.