Best cheap headphones I ever got

I didn't expect much from a set of headphones this cheap. I just needed a pair for a short trip. I was SHOCKED! by the bass response and volume level. Flat as a table and SOoooo low. I listen / DJ synth / Drum & Bass and Trance. Not many headphones are up to that task. These love the bass. The sound in not like a simple bass boost it is very flat bass. The upper mids are a tiny bit weak and highs could use a bit of emphasis. seems that the 2-4 kHz range is down a bit. Overall decent quality audio not the same as a a pair of Grado RS1 headphones obviously. But being $700 lower cost that is no shock. The bass is engulfing and amazing. The noise canceling is a alright, a bit of hiss in the high frequency range, seems to attenuate frequencies below 1kHz quite well. , Perhapses with a low pass filter added to the circuit that could be fixed. But then they wouldn't be a $30 set of headphones. Don't expect dead silence with these on but there is a big improvement. They do make a trip quite a bit quieter. Most engine and wind noise is reduced significantly.
Another feature is that you can have the volume up quite a bit and not disturb others. Nothing worse than someone sitting next to you with their Ipod cranked and you hearing it blaring.
I suspect that the NC is what makes the bass so nice. Like my Velodyne servo subs it is getting feedback and flattening the bass response.I suspect this was not intentional, but they didn't get a good seal between the NC pickup mic and the speaker, effect is like a servo correction system. I plan on trying these out next time I DJ to see if the NC feature works well in the club environment. I expect the bass will be very helpful there!
With the NC feature turned off these DO sound like a set of $30 headphones then. The magic is in the dongle, just keep feeding it AAA's for happy listening. The batteries seem to last for a long time, so it won't cost much to keep em sounding good