Easiest/Cheapest way to record megavolume sounds by iPhone 3GS

When you try to record a concert or your band play in a practice studio, are you always concerned about bursting volume by iPhone?
It's easy to solve it to buy additional microphone for iPhone that it specializes for recording in the situations.
But I heard some cheap ones don't work well.
SO, try my method to record before buying these ones.
It' easy and cheap.

Only you prepare before is a tape like this.



















Cut it off and just put it on your iPhone's mic tight.(Mic is on bottom right.)



















































(Sorry for dirty pics, the tape caught my fingerprint.)


Even if there's slight space, it catches sound voluminously.
So tight it up.
That's all.
Record what you want.

If it's still bursting, put one more on.
Believe me, this really works!
My vids on youtube proves it.
http://www.youtube.com/user/ray80

So, let's upload your locals on youtube.

Of course this works when you only record sound in a practice studio.
In my experiences, you should tape it several times in a studio.