So I have been comparing my working IMR headphones and thinking over the differences between the avalon and semper and older IEM's from memory (halcyon, and aten currently broken). I have used a bunch of songs and also pink noise to EQ each model to what is the most pleasant or least harsh whilst also not reducing any frequency into being unballanced and thought I would share my findings here. First is the semper
Above Semper and below Avalon has a dip at 1.8k which is normal to counteract how sensitive our ears are in that area (look up Fletcher munsons Equal-loudness contour graph for more info). The meaningfull EQ I applied is a gentle boost to the whole midrange (as semper is quite V shaped/recessed) and a sharp cut to aleviate the trebble issus I have at 7.5k leading to a harsh and sibilant experience which is my main gripe with the semper.
Compared to the avalon below and by extension Ozar which I find very similar in frequency response it has a gentle cut over the whole midrange as its much more forward than desired plus has two cuts to reduce harshness at 3.1k and 8.3k. I find that the out of box experience on the semper is more pleasant than the Avalon but I miss the more controlled bass and wider soundstage.
Comparing to my Halcyions and PB1 from memory, (so take it with a grain of salt) the Halcyon and PB1 are much closer to my ideal headphone exibiting far less peaking frequencies than the semper or avalon with both seeming to have a fairly similar response. The main difference to me was the detail and stereo width in the trebble (better on halcyon) and mids (better on the pb1).
The PB1 made me tear up when I first recieved them and I have not had such a positive response from the other models since and I have been a bit dissapointed with the peakyness of both semper and avalon. I may try to trade in and fix some of my models depending on what new models are in the roadmap and maybe feedback from bob.
I'm just sharing my findings here as someone may find it usefull. I created the EQ curves in Ableton live and I do a lot of sound work (mostly live) as my main job. I may try steal the PB1's off my partner later to do an EQ curve on those if anyone is interested. She got the PB1 and I got the Halcyons which my son broke. All earphones are on black black filters.
Also its worth noting that the harsh peaks I hear are most notable at loud volumes which is often what I listen to as they also get used for work and for mixing bands live. The avalons are superior in soundstage, bass control and detail but to me they are not the smoothest, ie can be harsh when loud.
