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Sending sound though a forest Condenser Microphones
Old 10th July 2017
  #1
Gear Nut
 
dimebucker5's Avatar
 

Thread Starter
Sending sound though a forest

Hi all,

I'm after some advice to capture the natural reverb of a nearby patch of pine forest that's about 200x200m (or 650x650ft). I regularly walk though the small forest and notice a very smooth, long decaying reverb when you clap or shout.

I plan to set up a PA at one end of the patch and set up my mics and recording equipment at the other. I will inject some percussive tracks and hopefully pick up the reverb at the other end (including ambient noises and birdsong).

I have limited gear and a limited budget, but hopefully if I get mic placement right, I should get some decent results

My main concerns are:
1. Should I put the microphones on the periphery or in the center of the forest?
2. Should I bother to try to capture a 'stereo image' of the reverb here considering I have two very different microphones, or would i be better of just capturing at different 'depths' and blending the results.
Thanks
Any help would be much appreciated


Gear:
Pre: UA 2610
Mics: Coles 4038 and an Sm7b
PA: Bose 1800 amp with 802's (using the correct Bose crossover)

Generator:Honda EU2000i - Enough power??




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Old 10th July 2017
  #2
Gear Maniac
 

It's even nicer and more useful to create an impulse response, so you can use it to recreate your forest reverb on other sounds.
Read this info about recording and reproducing an I.R (for impulse response), it's advised to play a sine-sweep instead of a short burst. http://designingsound.org/2012/12/re...lse-responses/
I guess the Honda generator is a no-go, because way too noisy. Definitely try to find battery powered stuff, or a car battery with inverter.
Old 10th July 2017
  #3
Gear Maniac
 
whippoorwill's Avatar
i would guess that those mics would be totally unsuitable for the task at hand.
ribbons and dynamics are noisy and do not resolve low level information well enough, especially for the amount of gain needed in the outdoors.
small diaphragm condensors are what you want and probably omnis to combat wind noise and present an open acoustic with correct tonality throughout the range.
A-B in the outdoors generally works well, I think about outdoor recording refinement almost every day though.
Old 10th July 2017
  #4
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dimebucker5's Avatar
 

Thread Starter
Many thanks for the replies, as you can tell i'm a complete newb in this field, but hopefully I can get some sort of result...


I actually have an Equitek E100 at my disposal if that would be of any use?

The only omni mic i have is that cheap Behringer one that everyone uses for room acoustics analysis!!

...maybe I could get some use out of the ribbon a bit closer to the source..less of the reverb but not so much gain needed?


Thankyou for the suggestion about impulse response, I will look into this!


About the generator, the EU2000 is a very quiet modern 'suitcase' type. It will be over a hedge and in the next field too, so I hope it wont be audible...
Old 10th July 2017
  #5
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esldude's Avatar
 

That cheap Behringer is probably the best you have for your purposes.
Old 10th July 2017
  #6
Gear Addict
 

I think you need to clarify to yourself what your goal is.

- Capture the ambient sound of the forest?
You don't need speakers or a genny for that. I would suggest the lowest-noise SDC omnis you can get your hands on (your Behringer ECM8000 is extremely high-noise and thus very ill-suited to this task). Go rent some Sennheiser 8020's or Schoeps MK2's for the day. You could also try M/S or ORTF with low-noise directional mics, but the recorded sound will not be as spacious and 3D.
Alternatively, you could look at a portable binaural recording setup if you really want to relive the experience of being there through headphones later. Low noise is key again - DPA 4060's are about the quietest you can get for this purpose.
Set up your mics, record the bird song and wind noises, maybe wander around an break a stick or two or talk and hoot and holler and bring some noisemakers of various kinds with you; I'm not sure what you want.

- Capture the reverb profile for use later?
You don't need speakers or a genny for that, either (though you could use them if you wanted, to do a sine sweep etc as mentioned above). Simpler - you could fire a blank or use some other strong acoustic impulse and capture the impulse response, and load it up in a convolution reverb. Again, high-quality omnis are the ticket, but you could also try other stereo techniques with directional mics.

- Re-amp some specific recording through the forest?
Your current plan makes the most sense, but again, use high-quality omnis instead. But what is the source material and what do you want it to sound like when you're done? The only thing you're going to end up with is the sound of the source track being played into a forest - is that actually useful to you for something?


These are three separate things and require three separate approaches. Right now, it sort of sounds like you have a vague sense of just capturing what it feels like to be in the place. Pick one of these as your specific goal.
I'm harping on about low-noise mics because I suspect you will otherwise be painfully disappointed by the noise floor you encounter once you turn everything up loud enough later.
You're also going to be disappointed if you don't go stereo, I think. It totally changes how ambience like this is perceived.

As for positioning, if you can use omnis, I'd set them up in the middle of the forest to get the feeling of being encompassed on all sides by the reverb. Start with 60cm AB spacing or even wider.
Use windscreens on the mics in all cases.

Last edited by dasbin; 10th July 2017 at 11:43 PM..
Old 11th July 2017
  #7
Lives for gear
I do a lot of audio work in forests. There's no hard and fast rules here - play around with different mic placement etc. However, if you like the reverb I suggest you create your own convolution reverb. Run a sine sweep - record the results. The convolution strips uses the sine sweep recording plus reverb (or whatever impulse response it uses) to create a reverb and hey presto you have your forest reverb to put on anything you want. There's a few good free convolution reverbs that will let you do this.
Old 11th July 2017
  #8
Lives for gear
Quote:
Originally Posted by dimebucker5 View Post
The only omni mic i have is that cheap Behringer one that everyone uses for room acoustics analysis!!
.
This is exactly the kind of mic you need to create a convolution reverb !!!!
Old 11th July 2017
  #9
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dimebucker5's Avatar
 

Thread Starter
Thanks everyone, this has been very helpful, I think I almost completely wasted my time!


Quote:
Originally Posted by dasbin View Post
I think you need to clarify to yourself what your goal is.


- Re-amp some specific recording through the forest?
Your current plan makes the most sense, but again, use high-quality omnis instead. But what is the source material and what do you want it to sound like when you're done? The only thing you're going to end up with is the sound of the source track being played into a forest - is that actually useful to you for something?
.
Dasbin, this is my main goal 100%. I am building a track with a dry percussive element (made on analog synths and shakers etc). I think it would suit that smooth reverb of the pine forest (it reminds me of plate reverb). I am looking for depth and an immersive quality to the track.
Regarding the birdsong, I have been there during the 'dawn chorus' and its insanely loud!!
I was planing to set-up before dawn and record through it to see what kind of ambience it would add. Definitely a secondary/unimportant goal!


So is everyone in agreement that my current microphones are completely useless for the task in hand? (aside from creating an IR with the Behringer, which is not my primary goal anyway)


..hmm, finding decent omni's out here in the west of Ireland might not be possible...


.
Old 11th July 2017
  #10
Gear Nut
 
dimebucker5's Avatar
 

Thread Starter
Quote:
Originally Posted by Gusss View Post
I do a lot of audio work in forests.
Gusss, do you exclusively use condenser omni's or have you experimented with other types?
Old 11th July 2017
  #11
Lives for gear
I think the biggest Achilles Heel might be the distant sound of the Honda generator, if you're going for faint reproduced sounds out of the PA ?

The weather might be a big determinant too...I think a cold frosty early morning or night, with next to no air movement, will give you the best conditions, as the still, dense air will help the sound propagate further...and the trees are randomly placed reflectors, giving you many reflections and source path lengths for the audio to reach your recorder.

Do a trial run first with a simple battery powered handheld recorder.....borrow one if you don't own one...rather than traipsing out there with an armada of hardware. An alternative is a mic tripod with very long mic cables...to get the recording gear well away.
Old 11th July 2017
  #12
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dimebucker5's Avatar
 

Thread Starter
Quote:
Originally Posted by studer58 View Post
I think the biggest Achilles Heel might be the distant sound of the Honda generator, if you're going for faint reproduced sounds out of the PA ?
I forgot to mention that i'd be using around 200m of power cable to get the generator far away and in the next field, behind a thick hedge.

Thanks for the suggestions about weather - i've also noticed that bone-dry weather conditions sound better than when its, well... dampened!
Old 11th July 2017
  #13
Lives for gear
 

I would be very careful about using a Coles 4038 outdoors -- the ribbons are notoriously fragile in the face of strong winds.

I also think the noise of the generator will be problematic. The hedge won't make much difference.
Old 11th July 2017
  #14
Lives for gear
Quote:
Originally Posted by dimebucker5 View Post
Gusss, do you exclusively use condenser omni's or have you experimented with other types?
Ive experimented with all sorts - I dont think Id use a dynamic mic though...I wouyld try and use some of those 240 volt battery packs rather than a generator. If you must use a generator you can get silent ones.
Old 11th July 2017
  #15
Gear Addict
Given that you want to record early in the AM and that even on a clear day it may be rather humid I would stick
with Sennheiser MKH20 or MKH8020
omni's. They are RF condensers and thus immune to humidity (unlike regular
condensers). They aren't cheap so rental
is the obvious choice.
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