[rustykpr]

I'm looking into building myself a pair of headphones as a bit of a diy project and just looking for some advice on picking out suitable drivers. Have been looking through the forum and have found many of the modding projects that others have done, like the T50RP and using donor headphones for drivers but really would prefer to start completely from scratch. I have done one electronics unit at uni, but have basically forgotten it all as it was only done as a core first year unit, so im looking to see if anyone could tell us if these drivers would be suitable?
 
http://www.ebay.com.au/itm/Harman-Kardon-1-75-Mini-Full-Range-Speaker-/150716147316?pt=Other_MP3_Player_Accessories&hash=item231761e674#ht_756wt_1163   
 
they would be the right size, I'm just unsure about their impedance as it is only 4ohms. I plan to read back over my notes and stuff from my uni subject before I start this project but as it is exam time at the moment my time is a bit limited.   

 

[rustykpr]

Anyone?

 

[symphonic]

If you're making your own headphones, I would strongly prioritize weight. Commercial products are generally heavier than they need to be, giving a sense of quality. I have transplanted T50rp drivers into a wooden body. If I were to do it again, I would go for a VERY minimal casing. You could get <200g with some effort. 
 
When I finish my PhD thesis in a couple of months I'm going to make some planar drivers and see if I can top the T50rp drivers, which really are very good.
 
If you use an amp like the O2 which has low output impedance, you won't need to worry much about the driver impedance.
 
For DIY I think that lightweight and repairable trumps ruggedness, and should be a design goal.