Stage noise in a church/auditorium (not a studio, but...)

knightfly · Post by **knightfly** » Mon Jul 28, 2003 5:45 pm

Hey Jeff - How's the hand, playin' any "Gweeter" yet? Hope so, that always bums me out...

OK, somewhat in order -

"Thoughts? Type?" - Yeah, 12" deep frames with 4" 705 FRK at the front, your favorite "man of the cloth" cloth over - that will get down to 300 hZ, pretty much FLAT - with all those various panels rattling around, that's a good frequency to get down to. Then, for the areas where people can actually REACH them, I'd stick with panel types (more durable) and you can do nicer wood that maybe fits the decor.

" Still think the baffling is a good idea under the stage? (hanging panels to kill resonances?) " - Yeah, but first I'd look at glue/screwing a couple layers of sheet rock under the floor, between the joists to lower the resonant frequency. Then, a bunch of cans of spray foam to broaden/dampen the resonance, then you might not need the hangers. If you do, they could still be done.

"panel bass traps along those walls I mentioned earlier?" - Actually, wherever they're up high enough to be out of traffic I'd go with the 12" deep ones I mentioned above - wider band absorption, unless you're already losing too much in the high freq's for good articulation of voices - the way you talked, it sounds like that might be the case.

"reface the choir riser with wood, atleast for their sake?" - What's on it now, carpet? Might be best to keep it, shoe noise and all that. Maybe if you put traps on the back wall they should be panel types, as I mentioned above you might already be losing too much sibilance for good articulation, that's the first thing that will cause lack of hearing in a choir.

Is there a chance you could get hold of an RTA (1/3 octave or better) and shoot the room (with everybody in it?) BEFORE you do anything else? I know it won't cover impulse response, but it would hopefully give you a clue as to evenness of response for steady state. I'd hate to steer you wrong by trying to guess from here what the room actually sounds like...

I'm planning on getting ETF Acoustic's package for my new laptop in a month or so, but I'm here and you're there and you'll probly be finished with this by the time I get any useful data, so how do ya spell phzhhfftt???

That's my offering for this Sunday, it's tired and I'm late... Steve

zikaj · Post by **zikaj** » Wed Jul 30, 2003 6:14 am

I'm at work.
Not free work. Job work.
So I gotta be brief and quick.
....ask my wife.......

get it.

nevermind.

I spent a hour or so yesterday playing a live CD - PearlJam if you care to know - through the house system and profiled each section of seats. I put together an illustration of the BLAST ZONES, as I call them.
As you would think, they are right in line with the horns and cabs in the ceiling- there are 4. And guess what- the FOH mix position is NOT in a position where it recieves ANY direct sound from the horns on axis. AND it is muddy in the rear of the house, where the board is. AND there is a 10'Dx12'Wx8'H hole in the wall behind the board; it used be stored in there during basketball.

So, the mix position isn't hearing/mixing what the crowd is hearing. Not only is it not getting the on-axis upper mids to highs, it has a sonic sucking hole behind it. (I can't prove the whole hole sonic sucker thing, but I read about it in another article that described the exact same set up) The last 2 rows of people don't get too much direct horn either. Kind of falls off at 3 rows up from the rear. There are fills for an upper balcony and the rear sides, which seem fine and not a problem (delayed, ofcourse).

I'm going to bring in my PC on Sunday- (hopefully I'll be in town) and get a listen and check out the f. difference and response of the room. I don't know how accurate it will be, but it will be better than what I have now (nothing except my ears).

Which mic type to use? It will be going through a MackiePreamp to a Delta44 card in my PC. I can get an SM81, 57, beta 58, ....probably a few others to choose from.

OH, and is this "SPRAY FOAM" toxic? If so, I'll ask them to close the lid on my when I go under there

......now where do they keep the communion wine?...

One last thing- I was going to save $13 a yard and use burlap on the rear stage panels- treated with Flamex, of course. Its black, and no one will see it, anyway. Cool?

Gotta run.

Thank a bag(j)illion.

Jeff

knightfly · Post by **knightfly** » Wed Jul 30, 2003 7:57 am

Can you post the map, including horn locations?

Any way of splaying the horn arrays differently, or are they one-piece/one bracket sort of thing?

If not, any chance of getting more cabs to fill in the holes?

Is the main system staggered front-to-back with time delays, or all one feed except for the balcony fills?

I think the spray foam is probably "happy snort" stuff, ventilation wouldn't hurt - it's sold here as "great stuff" - just generic foam sealant for weather stripping. Closed cell, mainly it'll just dampen vibes on whatever you spray it on. Thicker the better.

Use the SM-81 unless you can get an Earthworks Omni - flatter freq response. If you use a directional like the 81, check in several directions to see what the diff's are. Omni would be better if you can get it.

If you're using 700 series, or other rigid fiberglas, you might want to put a tighter weave on any that are within normal reach of bodies just to keep the fiber problem under control - even wrapping them first with something like those super-thin painting drop cloths would be OK, then the burlap over... Steve

zikaj · Post by **zikaj** » Wed Jul 30, 2003 8:36 am

Thanks for the corner bass trap Q over in "acoustics".

I just printed the data sheets from EAW on the arrays/speakers.

The mains are EAW MQV2364s...which means....Full Range 3 way system. 2 15" LF, 2 10" horn loaded MF, 2" exit Neodymium JF 60x40 beamwidth.
Added to that is a MF/HF horn on the bottom. Can't find the data on it.

I'd guess I can't move them. Maybe. But surely can't get more or those- $3600 each. There are 3 fills in the main area as you go back- they are delayed. As is the balcony. The fills on the main floor are MK219e- 2 way 12" LF and horn loaded 1.4" exit JF.

Wait! Now that I'm lookin at it, the HORNS added to the bottom of the mains are the horns in these things! So now I kow they have a 90x45 coverage. Nice.

I'll post the PDF of the map tomorrow am when I get a blink of time. heading to Pittsborgh now.

AND LAST- the panels are wrapped in polyester batting already. I am on the ball. And don't like itching! Or small cell lung cancer.

Thanks.

Jeff

hey- is the use of a monitor at the mix position to supplement the proper hearing a good idea? I can't find any ideas on this on the web. Thanks again. JZ

zikaj · Post by **zikaj** » Wed Jul 30, 2003 8:41 am

Just read the answer over in acoustics.

I forgot I asked over there.

Sorry for being redundant with this.

Hey, nothing like spending $20K on sound and finding out from a musician who went to school for nursing and knows how to read a few books about sound that you can't properly hear or mix in the place........

JZ

knightfly · Post by **knightfly** » Wed Jul 30, 2003 9:18 am

S'OK, I forgot where I answered what, it's easy to do.

In my book, a monitor at the mix position is the LAST thing I'd do, only if the DMI's (Decision-Making Idiots) refused to actually FIX the problem.

Way I look at it, not all your audience is getting their "tithes" worth - some are getting way too much mid/high, others not enough. Putting a monitor at the FOH mixer won't cure that. Changing to wider dispersion horns might, adding fills between the existing horns will. You wouldn't need the LF's, just the horns, and if they have a wider dispersion available it would be better.

At least they got time delays, but the question still remains - are they delayed properly? I'm not into this area much, so take this with a grain of salt, but I would think that you'd want even the MAINS delayed some, if they're very far in front of the stage - you want 885 microseconds per foot of distance, and if people in the forward seats can hear the pastor/music direct, then the mains should be delayed so they coincide. Then, if the next drivers were (say) 35 feet back, then 35 x 885 microseconds would be just under 31 milliseconds. If these #'s are off by much, it would decrease intelligibility by smearing phase in the high end, reducing enunciation.

I've tried to access Ed's (Sonusman) new Live sound site, but after the other day all I get is a 404. I was going to have him chime in here, he's just getting up and has a lot more live experience than I do.

$20 k isn't much for a decent large-venue sound system, it would probably help if the DMI's could be made to see this. Then maybe they would consider springing for some more fills.

Gotta go for now, Internet Deplorer is acting funny again and I don't wanna lose this before I post... Steve

zikaj · Post by **zikaj** » Fri Aug 01, 2003 1:07 am

Three brief observations and updates to the 'saga'.

1. My hand is healed. Got a few nice pink scars. Played my geetar last night and all is well. (did I mention I almost stepped on one of those impailing clips the other day....)

2. I mis-spoke when I said the system was $20K. It was WAY more. $40K in sound-reinforcement from what I can figure. Of course, $40K later, they still have upper frequency holes and nasty mud at the rear...

3. I went to rehearsal last night. From the mix position the band was at 88dB, C Weighting SPL; 80 A Weighting. WITHOUT THE HOUSE SYSTEM PLAYING. At the 3rd row, the STAGE VOLUME read 93 dB (C).

Not much room to "MIX" with, eh?

I am going to go there today and hide the bass amp, the guitar amps, and stack 200 cinderblox around the drums.

Then, I"m going to guild a SHELL around the choir so someone can hear them. Their mics- SM81s- are 80% STAGE NOISE AND CRAP and 20% voices. And because there is no gate, anytime they are quiet its just MORE NOISE!

And, heck, while we're at it, why not FEED IT ALL BACK INTO THE STAGE MONITORS JUST FOR THE FUN OF IT.

THANK YOU STEVE and Others. YOU KEEP ME SANE and HOPEFUL.

Jeff
I can't access my server to post the illustration of the set up. Server problem. Soon fixed, I hope. JZ

zikaj · Post by **zikaj** » Sat Aug 09, 2003 2:39 am

Just for reference to all of this, here's a pic of the overall space I've been working in. The mix position is immediately to the left of the rear entrance to the Sanctuary.
JZ

Here's the link:
http://www.churchontherise.net/images/c ... ry_350.jpg