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Michael Miramontes

Any advice on how to kill an echo in a large room?

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Marc, used SPL DeVerb recently - works VERY well, but needs a LOT of care (which i think is the way it goes with most plugins)...

I'm helping a friend out right now with a speech recorded at a Holocaust Survivor event, and the reverb and hum on the lectern mike was atrocious. Much to my surprise, not only did Waves WNS get rid of 75% of the hum, it also knocked down the reverb by about half, too.

I try to use re-recording mixer Marti Humphrey's rule: "taste plus 10%." Never go too far -- err on the side of less is more.

--Marc W.

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Hi guys,

As a (partial) side note, does anyone know where to source equally good sound blankets in the uk (or europe)? black on one face white on the other, with precut holes (gromets?) on the sides for hanging. Essentially the same as Jim's link. Thanks!

I don't, but I do know that it's not too hard to do your own grommets. I did that on a half a dozen blankets I got from Mover's Supply. The first grommet is scary because you think you're going to create some nasty hole that's going to rip and grow throughout the life of the blanket. Of course you don't, so then you're happily pounding grommets in for the rest of the afternoon, praising your own frugality and ingenuity. When you're done, you've got a beautiful sound absorbing device that's nasty on furniture, but oh-so-good on acoustical problems.

Not sure where you'd pick up the grommet kits in the U.K., but here's the link to Home Depot just to give you an idea what you're looking for. Something like this:

http://www.homedepot.com/buy/tools-hardware-hand-tools-fastening-tools-grommets/general-tools-1-2-in-solid-brass-grommet-kit-175929.html

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Excellent advice from all, but this wasn't stated specifically:

Prefer the acoustic solutions above to the mic choice/pattern/placement solutions whenever you can.

Both are good, but if you can tame the acoustics to "just the right amount" of reverb ("just the right amount" being definitely not so much as to be problematic in post, but enough to satisfy your working style ("looks like a warehouse ought to sound like a warehouse." style vs. "just give it to me dry as it you can get it. I'll add reverb later" style.), it gives you much more slack with mic choice/pattern/placement.

"Bad" acoustical sound is just tough to mitigate well with mic choice.

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I always use lavalier mikes in such situations, togheter with a directional mike - supercardioid or similar, no long interference tube - in a boom pole out of the frame, but closest as possible.

The close position of the lavalier in the talent usually "dries" the reverberant sound more than enough, and later in the rerecording sessions you can blend lavaliers and directional mikes tracks and achieve a right balance of direct and reverberant sound.

In a very big room it is almost impossible to use enough sound absorbing material to really make a big difference, and usually there's not enough time or production money to really do it well...

I almost never use sound absorbing materials to correct reverb times in rooms at all.

If you can't use a lavalier at all, negociate with the director and DP close up dialog shots, or have a "sound only" extra take with a close directional mike for the talents.

Tony Muricy

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In a very big room it is almost impossible to use enough sound absorbing material to really make a big difference, and usually there's not enough time or production money to really do it well...

I think that's especially true on a student project like this. I agree that the choice of using lavs is probably the best approach, plus a hyper as a boom track.

I did a post project a couple of years ago where a horror movie crew created a motel room interior inside a defunct high school sports building (formerly a concrete basketball stadium). I was sure it would still sound like a basketball court, but damned if it didn't work just fine. The set was completely enclosed, with a partial ceiling, and that was enough to damp out 90% of the reverb. I haven't seen the final, but I doubt they'll have to do much ADR at all for sound issues.

--Marc W.

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Great posts all!

If you can't hide it use it as if the shots portray the space then that's the reality.

Productions usually do not have the time or budget to deal with acoustics.

Yes use radios on actors to get direct sound and let post deal with it.

And yes loud actors are a problem and their decay can step on incoming lines.

I always love the producer or director who is on the location recce and claps their hands

and looks at me and ask what am I going to do about it!!!!

The answer is ask for old carpet or underlay to be hung around walls and over sets.

( in fact I have a job next week with this problem)

Provided you are seen to be pro active then who can fault the results - only those who chose the location!

I've spent 30 years recording in warehouses and factories AKA "studios" and I'm still doing it!!!

mike

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Ohcrap.

Deleted post came up with egregious formatting errors and I'm out of time to fix it.

Will post again later.

Oy.

-- Jan

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I'm about to start a TV drama where the location is Beautiful, but sounds like hell... AND the show is notorious for loud dialog/arguments/ scenes where wild sexing-giggle frenzy-loud business are involved.

The place is great, lots of natural light, open spaces... well you can see it. My chances of hiding blankets/sonex/absorben material are slim.

Any one has used ACOUSTI PAINT? Sound absorbent paint to help control reverberant spaces?

post-3017-0-64100000-1320793866.jpg

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I suggested making a false ceiling with heavy white cloth, carpets... etc... but I guarantee that when comes panic time, Mr Wide and TIght will come knocking and we'll be in a world of pain.

My last suggestion was to change location... (dunno about that)

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Lavs on the actors, boom from wherever you possibly can wind up to get the "room" in those wide+tights, so they at least have something to mix together to wet up the dry lav clarity...

Other than that, buckle in for a fun ride, b/c you can't do much more than rig the actors and hang on for the ride.

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I don't know if this has been mentioned - but a sound blanket well taped to the ground will help. It certainly won't kill the echo/reverb in an incredibly lively room - but it will give you a bit of a drier signal - and will certainly help with a serious early reflection.

That said - there is a stage here in Brooklyn that fricken everyone likes to shoot on these days - I think it must be the price - and there's no treatment save maybe the ceiling. Did a long commercial there where we hung blankets and put ones on the ground, but it did little help - there was a crazy slap echo that you could hear, especially on the main male talent. Even he pointed it out.

-greg-

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I've been on a few locations where hard parallell walls and/or large empty rooms have given me a lot of problems. I belong to those who prefer to treat a space as much as possible, letting post add the amount of reverb they want. I usually carry about a dozen furnie blankets and as many carpets about 1/4'' thick, which I lay on the floor, put on walls, and on C-stands to move them around closer to the actors. If we only shoot in one small part of a bigger room, I cut of the room much like in Richard's picture, sometimes creating a box around it.

This can dramatically improve a location and make the dialogue easier to make out, but I'm the first to admit that using only relatively thin blankets and carpets does not cut it for the more extreme locations. It absorbs the highs and some mids, but it leaves a lot of bass and low mid, making the room sound very "boomy". I've yet to try thicker materials, and I hope it will make a difference. I'm currently on the lookout for thicker carpets, and compact matresses 4''+ thick which I think will be the best solution for lower frequencies (since it's soft and can fold and adapt, unlike thin plates of plywood which while effective might be hard to set up in a good way). It will be a pain to load and unload it all though when going to location...

Reading up on some absorption coefficients, one thing to notice is that the values for drapes that are pleated to about 50% is more than twice as high as having them straight against the wall. Se for instance:

http://www.sae.edu/r...ent%20Chart.htm

http://www.audioreco...-treatment.html

This should apply to all soft materials, but pleating it 50% it would take up half the space. Has anybody compared, or dare to guess, if hanging it straight but using two layers, would give a better effect? Maybe the extra effect of having it pleated is becouse it creates a distance from the wall - in that case, using twice the amount of blankets, you could maybe separate the layers creating air between both them and the wall. But then again, that might be harder to do compared to just folding and pleating them...

Does anyone have any tip on other ways or materials to clean up lower frequencies (for dialogue, so mainly above 150Hz or so), that is also relatively practical?

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