[fir3st0rm9]

I am considering purchasing these because they seem like great portable headphones.  I hear they are durable and have great sound which is awesome except that I am worried that they will lack in bass because I listen to a lot of Dubstep/EDM and I like deep bass response in headphones.  So how do these compare to others in the way of bass?

 

[NA Blur]

They sound pretty neutral in the sub bass region and a tad lean in the low bass.  To me they are one of the best headphones for the price and definitely stand the test of time.  Keep in mind they are on-ear headphones so if comfort is a huge concern look elsewhere, not to say they are terrible uncomfortable.
 
Here is a frequency response comparison between it and the Denon AH-D2000.  The AH-D2000 is definitely pretty pure on the low end and as you will see the HE-25-1 is close, but with some obvious lack of deep bass.
 
http://graphs.headphone.com/graphCompare.php?graphType=0&graphID[]=2881&graphID[]=513&graphID[]=2941
 
I also included the Audio Technica ATH-M50 which is a great headphone considering it can be had for less than $150.  It is an excellent buy and would be my recommendation to you both for sound and build quality in addition to it being quite comfortable once the headband stretches a bit.  See how the ATH-M50 extends above both of the other headphones from 100 Hz and below?  That is some much needed bass.

 

[Bonobo]

They won't lack in bass. After receiving my O2 amp (today) and testing the HD25 with these, I was surprised by even more bass than with my Fiio E7. They are now my most bass heavy cans including my D5000, and my just bought DT990 Pro, believe it or not.
But it's definitely good bass to my ears. I still love the upfront sound of these!