I had the Beoplay 30, now have the Meridian 40. I'm not the best when it comes to description analysis, but I'll give it a shot. The 30 had a more forward and aggressive approach to my ears. The 40 is a bit more laid back, and more musical to my ears. The 40 sounds more airy and a bit less congested. Kind of an attack vs decay type of deal. The 40 has more breathing room, and a touch more distance, opposed to the more in your face character of the 30. The 40 sounds a touch wider with a more enveloping presentation too. There was some talk about the 40 not getting as loud as the 30, but it's just tuned differently. I went back and forth listening to both phones for about 5 weeks, before eventually getting rid of the 30. Some people say that they sound the same, but I highly disagree. If you read through this thread, several pages in the earlier portion talk about this. The 30 was great, but I definitely prefer the 40.