Building headphones ?

[pinenut]

Hey folks, I've decided to build a set of headphones based on some Howard Leight Thunder 29s I've picked up. Found some inexpensive 100 Ohm speakers I'd like to try, but they're only about 20mm in diameter. Pretty sure I can use two of 'em per ear and wire in series, making 'em 200 ohms per side... Anyone see a potential problem there?

Here's the speaker I have in mind; I've purchased a few sets already:

http://www.ebay.com/itm/131292533262

I'd appreciate any help or tips here... Thanks! ^_^

 

[duggr]

I use 50mm(2") speakers in my headphones
http://www.findmall.com/read.php?22,2262964,2280462#msg-2280462