How to choose a microphone for my requirements?

Question

I am in a need of a microphone for a specific setup and with some requirements, but I don't seem to have much luck in finding the best option. There is a possibility I am looking at this all wrong, so I am asking for advice here.

My setup is as follows:

• The recording device is an Delock USB audio sound card

• The USB sound card is connected to an Raspberry PI electronic board

My requirements are:

• It does not have to be professional quality, I am hoping for something in the price range of 30€. Update: I understand that this budget is quite low, so it can go up reasonably if other requirements are met.

• Small microphone (i think the terms my be: bug, lavalier, lapel, although I am not certain about the differences, but you get the idea).

• Optimal sensitivity (I have used Genius MIC-01C with the sensitivity of -58dB at 1KHz and it was ok, but I think I would rather go above -45dB).

• The most important thing is the noise requirement. I have had bad experiences with the Genius microphone, because its cable would collect too much 50Hz noise from the environment. If it was near the fluorescent lamp or a power source of any kind, the noise it collected was too high for any usage. Even when it is not near the EM source, it still gets much 50Hz noise from the environment. This is the main reason I am looking for an alternative microphone. I guess this requirement could be summed up as a need for a shielded cable?

• The directionality should be unidirectional the narrower the better, because it is used to listen to one person only and try to eliminate anything else whenever possible.

What i have found in my search so far:

(I can't post more than two links yet, so here are only names)

• Sony ECM-CS3
• Bronstein LM15
• Olympus ME52W
• UPDATE: Olympus ME-12 - how can i know if it requires phantom power?

UPDATE: The ME52W has proven to be a bad choice due to phantom power, which i can't supply.

My questions are:

1. Is there a microphone you know that would suit me these requirements?
2. The Olympus ME-52W is the best I have found, it has high sensitivity, noise reduction and it has direct 3.5mm connector so I can replace its cable with a shielded one very easily. But the question here is: can i use this microphone with my setup, since it is ment to be used with the voice recorder? Seems that it needs phantom power to work? How do I know if i can supply this? UPDATE: Seems that without phantom power this microphone is useless. Thus, i need an option that doesn't require phantom power.
3. How do i protect the microphone from collecting 50Hz noise from the surroundings with its cable? Should i use a shielded cable? Most mics come with their own unshielded cable, and replacing should not be an option for me..
4. Do XLR cables help with this? Can i use a 3.5mm to XLR cable and get an XLR microphone that is small in size?
5. UPDATE: After reading this discussion, I am wondering if my understanding about phantom power is correct for the Olympus ME-52W and ME-12 microphones? Do they indeed need the phantom power, or if this is something else. As quoted on that link:

   "Just plug the TP-8 jack into the "MIC" jack of your recorder"

Finally:

Thank you for your patience and I am sorry if my questions are wrongly directed or nonsensical. I am grateful for any help or hints as to how to direct my search.

Answer 1

If you go 50-100 bucks you would be able to get a good (seconhand) mic with a good Signal to Noise ratio.

The best low budget lavalier mics i came across where the sennheiser lavalier mics of the ew100 eng series.

If you can handle a normal size mic, go for the Shure SM 58. it is so versatile and a good 1st mic Option!

Answer 2

It's a bit out of your budget, but I'd consider a USB powered cardiod mic like the Audio Technica AT2020. It runs about $100 (though, you can find it cheaper) if you intend to use it with a Pi.

Going this route, you end up with (1) a better quality audio device (built into the mic) and (2) no need to worry about how you're going to power the mic, go from XLR to 3.5mm (all sorts of potential for noise there) (3) you've got all you need to get up and going (no need to get a mount, unless your application needs a shock mount).

There's a pretty good review of it here:

It does a fairly good job of cutting noise, and has the direction that you want.

Now, this is by no means a professional mic - but it is pretty good for one-off applications like the one you describe. Additionally, you'll find use for it beyond just this case, it's a really nice mic if you're ever doing a podcast, interview, Skype / Hangout / etc.

The down side is the same as the up side - it's USB, so you're pretty much restricted to using it with a computer - but that doesn't exactly describe a limited number of applications.

You could get something going within your budget, but it's not going to be very optimal. As you could use this for other things, it may be worth considering upping the cap a wee bit.

Answer 3

That is an exceedingly low budget. Forget professional, I think the cheapest mic I ever bought was about sixty quid, and it is just about okay.

Balanced cables will certainly help reduce mains him and other interference so yes, balanced XLR is essential.

If you have a mic that requires phantom power you need to have a way to provide it, whether that is a DI box with phantom, or a desk which can provide it.

Answer 4

1. i don't think you can find a quiet, sensitive, shielded-from-interference, directional, small, microphone for €20. but i could be wrong.
2. the ME52W will need a battery box to operate (plug-in power)
3. it needs to be shielded, with the shield connected to ground, that may or may not work, since the hum may be for another reason.
4. read this. also, likely, no.

If you're up for some soldering, and can grab out 3V from the raspi rails, I'm told the mythical BT-EM172 capsule from Sony's ass-kicking portable M10 can be found online on the cheap. it's -28dB re 1V/Pa :] It's not directional, and isn't shielded but you can address these.