I have IEM's and on one headphone inside, the cables tore apart from the speaker. So, I tried to solder it back, but I made a little mess(it's so small so I wasn't precise and I burned where I wasn't suppose to) so I am wondering is it possible that I did something that degraded the sound...

Yeah, but, since your girlfriend maybe it's better and cheaper that you give her some in-ears from Philips. Great sound and design. SHE9550 for example only 20 $  OR SHE2675/SHE3575   also around 20$. ADDIEM have a better for sound quality but I don't think it works great with every...

One word: ADDIEM  You can find em on ebay, 40 $ shipping included. 

if you're gonna rockbox then clip+, if not then Philips

depends which headphones will you be using with it. tell us this.

so?

Sell those, buy Apple Dual Driver IEMs, they cost around 40 $ on ebay(new), you won't regret it. Amazing clarity...I use triple-flange ear tips with them, gives me best seal, also available on ebay...

Quote: you stick'em in

Sony XBA-1

What about Etymotic ER4P ? Single BA for 300 $ ? you can get single BA for 50 $.

but all single BAs I've seen have smaller frequency range, usually just up to 10 kHZ and then they rapidly fall. Well ER4P are better but have weaker bass response in return. That's what I've seen from frequency graphs. I am talking about XBA-1 and Philips SHE 9850 for example...  

What's the advantage of multi BA over single BA if there is any? Bigger frequency range? Better response?

ADDIEM, duh. You can get them for 40 $.  

Quote:   well, you should open the phones and connect it to another cable from other phones. Recable them yourself! I've seen IjokerI doing that with Apple in ear, piece of cake. Phones are usually just glued. You should be able to open them with a sharp object like a knife in a right...

Quote: why would you need a removable cable?