Best mic for low frequency recording?

Hi all,

I need a little help here; this is going to sound weird but bear with me, ok? I'm not a sound engineer by any means...I am a paranormal investigator, and I'm trying to find out what omnidirectional mic would be best paired with a Zoom H6 portable recorder to capture low frequency voices. If anyone would like me to send a clip to see what I'm talking about, hit me up. I need to eliminate as much hiss as possible. Thanks in advance.

 

How low in frequency do you need to go? What sensitivity do you need?

The Zoom range of portable recorders is excellent for its intended function of recording music, speech and other normal sounds, but struggles with wildlife and particularly paranormal recordings due to the limitations of its pre-amplifiers in terms of gain, noise level and other problems of this world. You could try using one of the standard in-line signal boosters, as these would at least overcome some of the gain and noise problems. For an omni microphone, the lowest noise is usually from large diaphragm condenser units, so a low-noise mic like the Rode NT2-A switched to omni might work. If you use a signal booster with this type of mic you would have to get one that passed phantom power through to the microphone.

The last time I was asked to do a very low-frequency, low-bandwidth job of this sort I built an FM modulator, which allowed recordings of frequencies from about 250Hz down to d.c. using a standard cassette recorder. For a transducer, I recommended to the researcher that he try a geophone, and although those do not go down to d.c., it was possible for them to capture acoustic energy down to about 0.5Hz. I'm sorry to report that I never heard whether he recorded any paranormal activities along with the glacier creaks he was hoping for.

 

Thanks for the reply, Boswell; I'm not tied into the H6, I was considering buying one. What portable recorder would you recommend that would do a better job with the pre-amps? I am frankly not sure how low the frequency is as I have no way to measure it. When I tweak the recording I do it in Audacity, which doesn't give me that measurement. If you'd like I can post up a clip if you have a way to measure the frequencies of the voices. Thanks again for the help.

 

I'd be interested in hearing the clip.

More food for thought:

Voices through their normal inflections can cover a wide range of frequencies, rising and falling pitch fluctuations often communicate more than the words themselves - so there will be no set frequency to look for. But having said that, if it's audible to human ears it's most likely above 20Hz almost by definition. In which case, any reasonably high quality mic with low self-noise might be sufficient.

If the pitch of the voice is so low a normal mic can't accurately pick it up, then the Earthworks Measurement series mics, like the M50, are extremely accurate and boast specs spanning from the sub-sonic range (below 20Hz) to ultra-sonic (above 20kHz). The M50 in particular 3Hz - 50kHz ±1 / -3dB. Obviously that kind of microphone, with scientific research applications, doesn't come cheap. And again, a mic like that could very well be beyond your needs. And from that arises a whole new batch of problems it will take some like Boswell to figure out. (What medium can record 'audio' outside the range of frequencies humans can hear? / How will I playback those frequencies in a way that people can hear it?)

Fascinating subject, good luck.

 

Thanks, dvdhawk; I had to post a YouTube video with several of the clips in it..not seeing how to upload an actual audio file. The definition of the phenomena that I am attempting to capture (Electronic Voice Phenomena, or EVP) is simply a voice or sound that is not heard by the investigator at the time, but shows up on recordings on review. What I just uploaded was not captured on any of my cameras or other audio equipment at the time, and I was completely alone, out in the country. I think what I'm looking for is something that will go low frequency but not necessarily subsonic, with no hiss or noise for me to have to try to clean up. At least, I'm not there YET; I may well want to begin experimentation with that aspect in the future though.

 

A couple things, taking everything else at face value ….


A) I'm not seeing where a mic that excels at low frequency is as important as the low-noise requirement.

2) Isn't a certain amount of white-noise part of the phenomenon, as a canvas for the other sounds?

 

You are correct that the low-noise requirement is the most important thing, however I'd like to try a lower frequency mic as a sort of experiment to see if it is easier to capture them, since they seem to be buried at the lower frequencies. It hasn't been my experience as far as EVPs go that white noise is really a part of the phenomenon.

 

This is quite funny poppycock. Here is what you're also missing. A Boundary or PZM Microphone. In these types of recording applications, the nasty resonant frequency of the room is very obvious sounding. Making everything sound as if it was recorded from within a 50 gallon container drum. Yuck. The Boundary and PZM microphones eliminate much of that big hollow metallic resonant sound, that sucks. And when mounted on a large surface such as a wall, ceiling or floor, the size of the boundary on which it is mounted, dictates its low-frequency response capabilities. The bigger the better the lower it goes. Things also sound more on microphone than they do ambient. But assuming this is mostly all a hoax? You want plenty of outside extraneous noises. To make it sound like you are recording ghosts. Which must obviously breathe, otherwise they would make no sound. It requires air for sound to travel. Meaning that they are not ghosts but live people mumbling, that are being heard from afar.

Paul is dead.. Right, check, got that he's a fake. And so was the landing on the moon. Though while humming, Buzz might argue that? So that's not really a sound. It's Buzz... Aldrin.

That's one small step for man. One giant reach for ghostly kind.
Mx. Remy Ann David

 

I have what seems to be low frequency buzzing noises in various rooms ... Am prepared to purchase or rent equipment to get good quality recordings. ... Tips in terms of specific equipment such as microphones etc.

 

Can I just comment on this? When you say "I'm not a sound engineer by any means....." it doesn't matter what you say after - if you are a plumber or a paranormal investigator - if the thing you want to do requires (or should require) both professional tools and expertise to capture the sound of something with any kind of legitimacy that you intend to offer as proof of the existence of a phenomenon - then you are the wrong guy for the job - you need a professional sound or recording engineer or an acoustician. Basically a serious level pro with years of schooling, fieldwork and expertise behind him. That's not you.

Now that's not even to question the legitimacy of what you want to do --- but there is a world of difference between a bunch of guys running around the forest chasing Squatches, or dark basements chasing ghosts, with their boom mikes and anoraks, and a serious professional level effort with controls and expertise and knowledge.

It's not a crime that you don't know the gear or the theory (how to use the gear) that you should be using --- but at this point you gotta ask yourself: what does investigator mean? Is an investigator of phenomenon someone who has to do everything? Or should you consider yourself more of a project and team lead? In the Police world you have investigators --- but for the blood they call in the blood scatter guys -- for the gunshot angles and trajectories they call the physics guys - when they are trying to tap phones and record the bad guys making secret plans in their bunkers they call the sound guys ------------------ shouldn't this be what you want to do here? Call the sound guys?

There's no burden on you to actually call the sound guy ---- I myself am doing some home recording and I'm making do with some budget tools and my own lack of skillset -- but I also know that my end product will reflect that -- that my end product is and will be very far from what an actual pro level recording will be. For pro - I'd need (currently) to drag my ass down to a studio with an engineer and producer and lay it down. In this way for you too it would be perfectly fine for you to do this all yourself with limited knowledge and tools -- but your end product -- the recording and more importantly - the legitimacy or integrity of the recording would be of little to no value as far as actual controlled scientific documentation of the phenomenon.

So your question here about what to use really needs to be mitigated or vetted with what you intend the end result to be. You want to have a little fun - you want to bring your recordings out at dinner parties and creep your friends out? You want to inspire a reality television show producer with your unique personality and gumption? ---- these are all one level of tool and expertise ----- but if you want to call a press conference with the world's leading scientists and thinkers and religious leaders to offer your recordings as proof of the existence of spirits or some otherwise unknown phenomenon - then that's a different set of tools. And of course between these two scenarios there are variants or degrees of tools skillsets and personnel required.

So why don't you rephrase your question (or open it up a bit) and tells us what your intended end product is - and the guys and gals here can maybe help vet your expectations against the reality of what would actually be required to get there -- in the same way they do with guys like me who came here for advice on home recording.