Use of Lavalier PiP Mics and Question on power requirements (1 Viewer)

[Jon.Bryant]

I am thinking of trying to use a lavalier mic with a small recorder and battery pack to get close recordings of singing birds this spring.

I am thinking of purchasing a CLIPPY EM272 mono microphone, as this has better sensitivity and S/N ratio than most other lavalier mics I own (which came 'free' with F2 and Rode Wireless Pro).

The datasheet for the EM272 states 'operating voltage 5V'. I have two small recorders (Tentacle Track E and Zoom F2) that I could use, but I note that the F2 states that the PiP is 2.5V (the Track E says 5V),

Does anyone know if the Clippy EM272 will work with the F2, given the apparent disparity between PiP voltage and operating voltage - 2.5V cf 5.0V?

I would prefer to use the F2 with the lavalier, as I use the Tentacle with a different mic and may want to use both mics at the same time. Also, I would feel more 'comfortable' leaving the cheaper recorder unattended for a few hours.

 

[Jon.Bryant]

I wrote to Micbooster (who sell the Clippy) for a response and got confirmation that the Clippy EM272 will work well over a range of available PiP voltages. At 1.9 volts there is a slight drop off of performance but at 2.5 it will apparently work perfectly. A case of data sheets for the mic capsule not being straightforward or all that clear!

 

[Vollmeise]

Jon, Both tested the Primo EM272 and the PUI AOM5024L @ 2,3V PiP by myself, both working fine.

As an alternative You could try PUI's electret capsule AOM5024L. The 5024 is even more sensitive (-24 dB vs -28 dB), has the same SNR of 80 dB and a PiP range from 3V to 10V due to it's specs.

 

[Jon.Bryant]

As an alternative You could try PUI's electret capsule AOM5024L

Thanks for this info. A question - is this available as an end product, or is it a case of buying the capsule, cabling and plug, then doing some soldering?

I was always a bit clumsy at soldering when we did odd bits and bobs at school.

 

[Vollmeise]

Jon, I don't know if it is available as a ready to use mic. Did solder my mics by using TRRS-jacks, cables, home made housing and heat shrink tubing. A fiddly job indeed, but You're free in modifications. For example, you can solder two capsules in parallel to further increase sensitivity and reduce noise.

Cheers)

 

[Elkhornsun]

Lavalier style mics come as omni directional and cardoid pattern mics. For your planned project the cardiod type are going to provide better results.

 

[Jon.Bryant]

Lavalier style mics come as omni directional and cardoid pattern mics. For your planned project the cardiod type are going to provide better results.

Thanks for the advice. However, I was really just worried about the PiP - apparently PiP is not a single standard, and devices supplying a voltage at the lower end of the specification, can potentially not be compatible with some PiP microphones that may require a higher voltage to work efficiently.

I think a omni will probably be fine for what I am trying. I want to try and get the mic as close as possible, but I wont be able to 'aim' a cardiod. With an omni, as long as the bird is within a few feet of the mic I will be fine, but with a cardiod it would need to be a few feet 'in front' to get the best results.

With a really close recording, I am hoping that the signal will be so strong, as to mean that I do not need a directional mic to reduce ambient noise. I have heard that others are using this technique for mono recordings of particular species - and professional music recordist will always optimize the position of the mic, so I think it is worth a try...

 

[Elkhornsun]

I suggest rethinking how you are approaching this project. Small lavalier like mics are used to record insects and general ambient noise but are not good for recording bird songs where a cardiod mic is going to produce much better results. The cardiod can be found that are self-powered with a single replaceable battery and provide a stronger signal to the recorder.

An inexpensive mic is the Audio-Technica AT8024 that has the option of recording mono or stereo (mid side stereo) with a switch and sells for only $249. It can be operate for days on a single AA battery and has a 3.5mm output plug.

Consider also how to avoid handling noise with the mic and this is easiest to accomplish by mounting it to a stand and using a cable to run from the mic to the recording device.

There are websites devoted to nature sound recording as well as this group

[email protected] | Level settings for field recording

groups.io

 

[Jon.Bryant]

I suggest rethinking how you are approaching this project.

I think you perhaps misunderstand what I want to do. The idea (which I know others have done, including a BBC Wildlife Sound Recordist), is to

1. study a bird and work out where it is likely to sing from
2. place a concealed mic as close as possible to this location
3. leave the recording device in the field, and recording
4. retrieve the equipment to search the files for vocalizations.

A variant on this would be steps 1-3, but then retreat and watch from a distance. Then note the species and time that any species vocalize in close proximity to a mic.

If we look at how birds were historically recorded, then it is not far off from this scenario. Most birds were previously recorder with open mics placed close to a song post or sometimes at a nest site. It is only the advent of shotgun and parabolic mics, that have provided options for more distant recording (although with a shotgun the frequency balance will always be as per the recordists ear - a bird 30m away will always have attenuated high frequencies, and will always sound 30m away no matter how loud you play it - this later point could be why some recordings are less effective when used in playback experiments - the recording sounds to the target like an ultra big and loud bird, but at distance).

Chris Watson (the BBC wildlife recordest) used a lavalier (I suspect omni) to record sub-song of a White-throated Dipper on a fast flowing river - a task that would have been impossible with a shotgun or parabola. Only by placing the mic discretely on the rock where the bird sang from, was it possible to get an ultra loud recording without undue river noise, and negating the need to apply gain, which would have boosted the whole, including ambient noise.

Sound Intensity is inversely proportional to the square of the distance, so by getting a mic as close as possible, you definitely massively increase the level of the target, thus meaning the influence of ambient noise should be reduced - that said, I have had insects vocalize right next to my mic and ruin a recording!

As an example of the advance of close recording, if you are 10m from a bird and 20m from an unwanted sound source, but then improve the mic position to 1m from the bird and 20m from the unwanted noise, the ratio changed from 1 to 4, compared to 1 to 400 - a hundred fold reduction in the ratio of unwanted noise. A shotgun is never likely to produce this type of reduction in unwanted noise, as the diffraction tube if only really effective at higher frequencies. My long gun Sennheiser ME67 only reduces noise up to 1000Hz noise, at 60 degrees to the mic, by 5dB (so less than 4 fold), but is much better at rejecting noise above 2000Hz. Even at 180 degrees to the mic direction, a 125Hz sound is only reduced by about 8dB (less than 8 fold).



Close placement of a mic is also the principle that most music recordest use - place the mic in the perfect position to catch the individual instrument or vocalization, rather than using a directional mic to reduce unwanted noise.

Anyway, time will tell, whether the project is worthwhile, as I have purchased the kit and will be giving close mic placement a whirl come what may