Pros: Very good mids and highs, crisp bass, good articulation, no distortion
Cons: Not very comfortable
These headphones are quite good, and have really great highs. They are an improvement over the SR-80i, with a more balanced and bright sound with better articulation. For the money, they are quite good.
These headphones do need to be broken in a bit. The highs start off a little harsh and tinny, but end up pronounced, but more balanced. They also need to be amped to get the full sound. Without an amp, they are dead. With an amp, they are brought alive, and have more bass and highs.
The place where the SR-125i's really shine is in the mids and highs. They are bright but accurate. and they have a little punch that really adds to music. They also have good direction and and have a very bright sound.
The bass, however, is lacking. It is there, but more for support than the main exhibition. It retains a very crisp sound and also has a little punch to make it stand out. This sounds really good depending on what type of music is being played. Music from the band This Town Needs Guns (a math rock band) sounds incredible on them.
Soundstage is another point to consider. Its pretty much not there. This makes the SR125 much better for certain types of music compared to others. They really sing on most rock music, but when it comes to acoustic music, like Sun Kil Moon, a lot is lost in translation. That type of music really begs for a large soundstage, which the 125's don't have.
The worst thing about these headphones is the fact that they are not very comfortable at all. The headband really digs in after a short while listening. I have found that this discomfort can be overcome by placing a sock between the headband and my head. It makes the headphones much more enjoyable, but looks rather odd.
I got the chance to compare these headphones to the Grados Labs SR-80i, and I prefer the SR-125i greatly. The SR-125's seem much brighter and better balanced than the 80i,
The main reason I purchased these headphones is to act as a counterpoint to my Audio Technica ATH-A700s, which have a massive soundstage.
Something to note: The SR-125i's have a large, thick cable and a 1/4 inch connector, so a 1/4 inch to 3.5mm connector is needed.