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ZEISS DTI thermal imaging cameras. For more discoveries at night, and during the day.

Microphone for home-made field recorder (1 Viewer)

Torchepot

Well-known member
United Kingdom
I've got the nocturnal passive recording bug and want to leave my recorder (Tascam DR-05) out in the field at some remote places locally.

I'm worried about exposure to the elements so I intend to seal it in a sandwich box type container with a power bank and dessicant pack.

The problem is making an effective seal around the built in microphones is tricky and I need to be able to access the recorder easily - plus I'm not sure how weatherproof they may be.

The simple solution seems to be an external microphone but I don't want a shotgun mic or need anything stereo. I'm thinking of something like this in the bottom corner of the photo - but don't know who makes it.

Field microphones.jpg

Any suggestions would be most welcome :t:
 
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I’m using a pair of these with my Sony recorder (which apparently uses the same capsule internally), and I’m told they work well with Olympus recorders.
http://micbooster.com/primo-microphone-capsules/10-primo-em172-z1-microphone-capsule-with-wires.html

I put the recorder in a clip lock box with some D cells, then the box goes in an insulated bag. The mics are mounted in a wooden box thing, with a lycra cover oversome wadding for wind protection. I put a plastic lid over the box as a roof, held on with elastic.

I’ve had this out in the wearher for several days at a time in wet weather, but I still don’t like doing it.

I find it very cumbersome, and I’ve been thinking of trying just putting the recorder inside half a plastic drink bottle, tied upside down to a tree. The sound wouldn’t be as nice, but it would far easier to carry.

I’ve heard of people putting up a small tent to put it in, or putting a condom over it.
 
Many thanks pshute :t:

I think that's just what I'm looking for. Can you tell me if it matters which way round its wired to a mono jack - I don't have any experience wiring a microphone capsule and don't know if they have a "polarity"?
 
Many thanks pshute :t:

I think that's just what I'm looking for. Can you tell me if it matters which way round its wired to a mono jack - I don't have any experience wiring a microphone capsule and don't know if they have a "polarity"?
I must confess that it's been so long since I wired mine up that I don't know! I'll see if I can find out.
 
Interesting, I didn’t know they had that product, and they’ve got a foam cover available for it too.

I’ve heard these capsules have some water resistance, but that page warns they aren’t water proof. I’m interested to know what you come up with to protect it.

The answer to your original question is yes, they have polarity. The ground terminal as indicated on the information sheet linked on the site must be connected to the ring closest to the body of the plug. Not sure about a mono plug though, I think it would short one channel to ground.
 
I've ordered one and the foam cover too. :t:

I'm planning to simply attach a bit of over-sized plastic covered with camo tape to the box with elastic bands which will project over the microphone like a little roof - like yours. I have some nifty home made screw-in tree mounts for my trail cameras so I may strap a plate under the box with the same bands to attach the mount to.

I'm worried about someone finding it - lots of hunters in the woods at this time of year, but mostly at weekends. Of course the advantage with the recorder is that it doesn't have to be sited on a trail to pick up calls. I have some camo scrim which works well - I've got video of a hunter standing right next to one of my cameras who didn't see it. I may try to shin up a tree a bit though to get it out of sight.

Still getting surprises almost every night which can be quite addictive! I can see some potential for research with these little gadgets - especially for species that don't call that frequently.

Had a nice recording of barn owl recently and I have another recording where I can hear a second distant bird responding.

View attachment barn owl v close.mp3

What do you do with your recordings? Such amazing sounds in Oz!
 
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I usean OldBird mic - http://oldbird.org/21c.htm - which has never had issues in the rain. Clingfilm round the mic capsule / parabola and then gauze over the top which is acoustically transparent but dissipates larger rain drops on impact. People leave these out for weeks in rain and theyre used in a lot of remote recording stations.
I wouldn't cover the roof in plastic as you'll impact the signal heavily ;) And moisture can get in the sides. Clingfilm is safer.
 
Thanks for the link Dominic - a bit out of my price range I'm afraid ;)

I'll certainly experiment with the cling film idea. :t:
 
If you're specifically after overhead flight calls, yes, forget about the solid roof idea. In my case I'm just recording ambient calls, and it doesn't seem to affect anything.
 
Thanks for the link Dominic - a bit out of my price range I'm afraid ;)

I'll certainly experiment with the cling film idea. :t:

Somewhere there are instructions for building your own bucket mic. Would work well to collect the signal with the mic youre talking about as well as provide an easy way to protect from weather. i'll see if i can find them
 
Hi Torchepot,
would that microphone be "better", i.e. pick up more calls, than the internal mics, on for example the zoom H2N?

Peter

Hi Peter

I don't expect it to be "better" than the built in microphones on the Tascam - which to be honest continue to surprise me. If I was confident that I could make a weather proof set up for the recorder I wouldn't bother. This way the recorder can stay nice and cozy in it's snap lock box and I only have to worry about the microphone, which is relatively cheap to replace - or at least the capsule is.

I have a shotgun mic which does out perform the built in microphones but only if you're pointing at the source. For a passive set up which needs to be as inconspicuous as possible I think this may be my best option.

It's being shipped to my family in the UK who'll send it on - so I should know soon.
 
Hi Peter

I don't expect it to be "better" than the built in microphones on the Tascam - which to be honest continue to surprise me. If I was confident that I could make a weather proof set up for the recorder I wouldn't bother. This way the recorder can stay nice and cozy in it's snap lock box and I only have to worry about the microphone, which is relatively cheap to replace - or at least the capsule is.

I have a shotgun mic which does out perform the built in microphones but only if you're pointing at the source. For a passive set up which needs to be as inconspicuous as possible I think this may be my best option.

It's being shipped to my family in the UK who'll send it on - so I should know soon.

My recorder has paid for itself over the years! so it does get mistreated, and is surprisingly sturdy, e.g. no ill affects after being left out in light rain overnight.
So I wouldn't personally invest to safeguard it, but would spend a small amount for improved quality or "range". I'm thinking the separate mic would be easier to hook up to a parabolic style reflector perhaps. The "bucket mic" sounds interesting, i look forward to hearing more about this. google didn't help me!

Will be interesting to see how you get on.
 
Thanks Dominic

I'd be most interested :t:

Found this overview:

http://www.nemesisbird.com/bird-science/night-flight-call-primer/

and more details here for making your own:

http://oldbird.org/mike_home.htm

Its definitely something that can be cobbled together with a bit of experimenting. WIth this system you will collect sound from a roughly 60 degree cone in the sky. It's very effective. I also use mine remotely in some woodland near my house for remote and diurnal birds.
 
My recorder has paid for itself over the years! so it does get mistreated, and is surprisingly sturdy, e.g. no ill affects after being left out in light rain overnight.
So I wouldn't personally invest to safeguard it, but would spend a small amount for improved quality or "range". I'm thinking the separate mic would be easier to hook up to a parabolic style reflector perhaps. The "bucket mic" sounds interesting, i look forward to hearing more about this. google didn't help me!

Will be interesting to see how you get on.

After waiting 27 days my microphone finally turned up! (My sister - bless her - wrapped it in the smallest parcel I've ever seen - it's a wonder it ever got here at all!)

I made a test CD of three calls looped - Bittern, Nightingale and Goldcrest, then played them at a distance of around 30 metres. I recorded first with the "naked" recorder pointing directly at the source then again with it turned side on at 90 degrees.

I then connected the microphone and without altering any settings repeated the process.

Listening back there's not much to choose (to my ear) between the two forward facing recordings (though the spectrograms look a bit different).

What's interesting is that the 90 degree recordings are clearly better with the microphone (the opposite of what I expected)

I'm pretty chuffed with the results and when I get a moment I'll post a comparative clip and hopefully someone can explain to me why the spectrograms differ.

I'll post some photos of the completed remote recorder in it's weatherproof container too.

Tomorrow (if it stops raining long enough) I want to compare recordings with and without cling film over the mic capsule.

It may be a while before I try the mic in a "bucket" recorder but it looks ideal. There's a cheaper version without the ruggedized mount which I'll likely use.
 
Got my wish - it's not raining - it's snowing instead!

Here's the spectrogram of the test. It's in four parts - as explained above. The differences are most noticeable in the Bittern calls (the dark blocks at the bottom) when comparing the second and fourth block (90 degree recording) and there's more detail in the Nightingale recordings.


Mic test spectogram.jpg


The difference in performance is most noticeable when looking at the waveform (dB)

Mic test waveform dB.jpg


Looks like a much stronger signal to me, but I hope someone with a clearer understanding might shed some light on the comparison.
 
Hi Torchepot,
would that microphone be "better", i.e. pick up more calls, than the internal mics, on for example the zoom H2N?

Peter

Hi Peter if you're out there,

I was wrong - it looks to me that this little mic outperforms the two inbuilt ones on the Tascam!

Cheers

Phil :t:
 
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