Mic'ing up science experiments...

[Ike]

I've somehow got myself involved with an outdoor science demonstration. The aim is try and convince young people that science can be fun, we're going to be doing the usual experiments (group I metals and water, jelly baby and potassium chlorate, nitrogen triiodide, liquid nitrogen stuff etc etc etc) and we've got the usual budget of whatever we can find down the back of the sofa.

 

Now most of you know I don't do sound but I've been roped into providing sound reinforcement for this on the basis that it was just a bit of speech and even I couldn't get it that wrong. Well now it seems I'm also mic'ing (sp?) up the experiments and I'm completely stuck!

 

We need to be able to reinforce everything from a bit of sodium fizzing round a bowl to (hopefully small) explosions and need whatever mic we're using to be far enough away that it won't get covered in crap (rifle mic?) or be cheep enough that we can buy one just for this event (say no more than £40). Anyone got any thoughts?

 

Also what would you do with the signal once you have it? Should I just shove it into a channel with a fairly flat EQ and guess at where to set the gain or is there more to it than that?

 

Thanks folks

 

Edit: SPAG

[fatfrog]

Set of RODE NT-5's.

 

They'll set you back around 200 pounds but they are very useful and highly sensitive and as such you can situate them far enough back so that they don't get soaked, blown up etc etc

 

HTH

Alan

[6th Order]

I'm sure certain members of the Forum would gladly lend you their C1000's if you promise to blow them up at the end...

[bruce]

I would have thought a budget small diaphragm condenser with a foam windshield or pop filter to protect it... treat the windshield as disposable

[mervaka]

I'd agree that rifle mics with windshields would be okay. will there be any sort of windbreak behind you though?

[Chris L]

I'd go for any sort of condensor mic with a windshield as it's outside ;). If you can get hold of any of "those fluffy things", they work very well for removing noise from wind, allowing a clearer sound from the source.

For some of the experiments it would probably be ok to put the mic fairly close, eg. if a small amount of sodium is used. Especially if it's a cheap one treated as an expense for the event. It might be worth looking at some of the experiments to be performed and seeing how close you can get the mic for each one as we all know closer generally = better ;)

 

EQ-wise, I'd go for fairly flat, maybe do a couple of tests and have a fiddle to see if you can make fizzes and pops a bit louder with EQ.

Gain-wise, you'd probably have to change it for each experiment, as fizzing tends to be fairly quiet and hard to make out from a noisey background, whereas a bang or a pop could be a fairly large pressure impulse for the mic. Again if possible, fiddling would be the best way.

As a good starting point, try to get someone talking at a "projecting" level about a metre from the mic to be audible.

 

Samson make a budget condensor that isn't the worst in the world, at £48 here: http://www.dolphinmusic.co.uk/page/shop/fl...product_id/4399 (might be less elsewhere)

 

HTH and best of luck

 

Chris

[Jivemaster]

Looking in Maplin .co.uk there are some electret capsules for £3 and a tie clip mic for £10 among their offerings. These could be built in to experiments and disposed afterwards. The noise of pouring liquid into test tubes.

 

Try a cheap tie pin mic on the presenter's thumb! Pick up all the glassware noises - bottles being opened things being poured. Another tie pin mic inside the rim of the water bath ready for the sodium. Any experiments with NI3 will need a hard knee compress/limit as will anything using black powder. Thermite usually fails to light at the right time and is hot and bright.

 

Trouble is that chemistry also needs colours and smells - truly evil smells

[palantir]

What about a couple of these? from CPC

 

 

G185BA — UNBRANDED — BOUNDARY CONDENSER MICROPHONE

 

Fidteen quid each - if the experiments are on a table they should work

 

Pete

[Rob_Beech]

Thomann EM800's Fantastic. under £50 a pair. Great sounding mics, my first choice for hats and acoustic guitar* Great for ambient recordings etc etc aswell.

 

 

*as part of a pair of different mics.

[Ike]

Great stuff. The location will be open on two or three sides so could be fairly windy. Presumably something like the EM800s would have internal wind shields but I might need an external one as well depending on the conditions?

 

How easy is it to kill a condenser mic with a very high SPL, say peaks of 170dB or more? Obviously I won't be reinforcing these but it would be nice to not have to move the mic out of the way.

 

Thanks

 

Ike

[Rob_Beech]

You could try something more directional and put it further away. How accurate does your recording need to be?

[Ike]

Not very. Just need a pop to sound like a pop, a hiss a hiss etc.

[johndenim]

Very funny 6th order!

 

Any cheap CPC mic would do, Maplins are also a great idea. you will get a simple "pop" and fizzle with most omni mics, cheap mic nice and close, destroy it, for £10, just buy another.

Condensers would be better, but why pay more?

 

John Denim.

[PoppaDom]

Behringer C2 Pair, about £40 and for the money sensitive enough for what you need and classed as disposable. They also come with wind shields and stand adaptors....what more could you want?

 

Poppadom