Sennheiser MKH 20 and Wireless
 

I am looking at capturing infrasonic sounds (from wildlife - tigers and elephants) between 12-20 Hz which is beyond our hearing range. I find one microphone Sennheiser MKH20 which can record sound from 12 Hz onwards. The question is how close do I need to place this microphone from the subject. They are wild and won't be too willing all the time. :-) Will 4-5 feet be ok?

My second question is: Can I pair this with a wireless transmitter like a Sennheiser G3 or something? The Sennheiser G3 has a frequency response of 40Hz to 18Kz. Does that mean, I will be sacrificing the infrasonic sounds? ie. Will I be only able to record from 40Hz upwards and not below that?

And will the wireless transmitter provide phantom power?

Am I missing something somewhere?

Is there a cheaper microphone that can do the job?

Cheers,
Sabyasachi

Sennheiser G3 has a frequency response of 40Hz to 18Kz.. i haven't checked this,. but I'm sure teh response is far from flat at the high and low ends of the spectrum.

Will 4-5 feet be ok? As close as possible, but that should be adequate.

I am confident of moving in the mic to about 4-5 feet of the subject. The only reason I am thinking of wireless, is because the subject will get spooked by the wire. And if the wireless system (G3 or anything else), if it can't help in transmitting the lower frequencies (<20Hz which the mic is capable), then the purpose is defeated.

The MKH 20 is flat down to 12Hz - it can also have a simple modification done to go down to 5Hz.

The new MKH 8020, which is much smaller and less conspicuous, goes down to 10Hz.

If you want these very low frequencies you cannot go wireless as the bottom end of the wireless systems is above the frequencies you want.

If you want it hidden I would go for the MKH 8020 with the remote cable - it halves the size of the mic. and the remote cable is very thin, flexible and inconspicuous.

I hope this helps.

What is your plan to actually record, distribute and reproduce such low frequencies successfully?

John,
Thanks a lot for your response. How long can be the remote cable?

Cheers,
Sabyasachi

I'll echo Jay's question... it's the rare playback system that can actually reproduce much below about 75Hz, no matter what the manufacturer's specs may claim, at least for consumer grade equipment. What's the point of the expense of recording such infrasonics if almost no one's playback system can reproduce them?

Hi Jay,
I have certain thoughts for a research project and hence picking brains of sound experts here. I am sure there may not be a single person in this entire world who can hear such frequencies. So there is no intention to distribute as of now. I have bought a low end tascam recorder thinking that I can place it at a distance and switch on recording by a wireless remote. I will invest in better quality mixers and recorders later to record good quality sound when I feel the need.

Its just a crazy passion watching wildlife, photographing and working on conservation issues. Thankfully, I do have a day job and not too many vices to indulge in these kind of money draining stuff. :-)

Since I am a newbie interms of sound recording, any tips from anyone would be highly appreciated.

Cheers,
Sabyasachi

As long as you like - standard lengths are 3m and 10m, I know some people have had 5m - you can get any length you want to order.

The MKH 8000 series microphones are all in the head and the XLR bit is just a connector converter with no electronics. The head outputs fully balanced audio at normal mic. level (actually a bit higher).

I hope this helps.

It's worth noting that wavelengths at that pitch are longer than five feet so standing next to the subject may actually be too close. You may find that if you stand within one wavelength of the sound source that there is less sound than being further back.
Something to consider further.

Hello,

interesting topic. I remember a story of a guy recording whales. He was recording to two track reel-to-reel system and had his mic deep under water. He thought he was not getting any (whale) sounds recorded until he speeded up the reel machine which brought the very low sounds of the whales up in pitch to audible range for humans.

Wireless is probably a no-go - there is more than likely to be a lowcut filter. Check out also your recorder's filters in the analog to digital converter. I would prefer something from Sound Devices or other professional level gear to Tascam, but Tascam may work just fine here. You can try recording sine wave straight from an oscilloscope or even some analogue synth and then examine the recorded signal if there's still information in the low end.

Wavelenght for 12hz would be 27,8m (93 feet). You can place your mic closer than that though. The good thing about low waves is that they can be 'heard' better from a distance so this might work for your advantage. 4-5 feet proximity of tigers ?? Not me :) Let us know and 'hear' your results.


Antti

Dear Sabysachi,

In my opinon, in this very special case, one would not need to get close to the sound source.

From what I have read, elephants, use these sub-sonic frequencies to communicate over very long distances.

There are special microphones designed for recording very low frequences.

You could try Sennheiser and Schoeps websites.

Microphones don't work under water - he would have been using a hydrophone.

It might've been hydrophone or a condom on his mic. Good point though, I'm not sure if'd trust thin latex, atleast for more expensive mics, but I've heard people using them.

I would never use a condom or the like.

Actually a friend made some excellent hydrophones himself.

Firstly - remember that 1) sound travels very well through water and hard substances, and, 2) a microphone needs air to work.

So - what he dis was to take a couple of those small, very dense and very bouncy, balls and drilled a hole in them, slightly wider than the mic. and finished just beyond the centre.

He then dropped a small tie microphone (Lav if you are in the USA - in the UK Lav means something different) into the hole so that the diaphragm was in the centre of the ball - there was a small amount of air round the ball for the microphone to work with.

He then sealed the top of the hole with silicon (bathroom sealant), it went into the hole but not too far down.

The density of the ball makes them sink and they make excellent hydrophones.