I think that using pieces of music you know well is often a very good way of picking up the "overall" perceived differences between two IEMs (or the same IEM through different sources/setups), providing volume matching is taken into consideration prior to any listening sessions. I tend to concentrate on the overall impression a piece of gear leaves me with while listening to some of my favourite tracks, and then home in on specific bits of the sound to run some proper A/B comparisons with tracks I know focus on those particular ranges.
I should point out that I'm no guru and write reviews for the fun of it, so please take my opinions as just that, an opinion on how writing about something as subjective and ephemeral as sound makes the most sense to me.
I tend to only listen to classical fusion (Escala, 2Cellos etc) or film scores if I'm dipping my toes into the orchestral world so am pretty uneducated in terms of the wider classical works - are there any particular movements or symphonies you would recommend to someone that would be good for evoking emotion or for review purposes? Always love to hear what other people use as their benchmark for assessing sound.
Same here, I also write reviews because I enjoy writing, and the critical listening I actually do for a completely different reason (music therapy/managing my ADHD). I am also still really new to it all and have only written two reviews of which one I initially just called my impressions, but was considered by others to be good enough as a review so I put that one up as well.
Using symphonies and other classical music I think requires a little bit of extra work, at least that is how I do it. I often study the background and story of a piece to provide extra context. So, for instance, I love Beethoven's Symphony No.3, Eroica, because it was written to celebrate the revolutionary achievements of Napoleon, although after he declared himself Emperor, Beethoven removed Napoleon's name in a fit of anger. The symphony therefore has this strong revolutionary theme that can be powerful and it ebbs and flows.
More specifically, I use the Nutcracker for treble performance because so much of the piece is presented through delicate high tones, like fairies buzzing in your ear. Really interesting (and I did this in my Ares II review) is that as the clock strikes midnight the atmosphere in the piece turns dark and that is where bass performance suddenly becomes a key part.
Another piece I love using for bass is Ma Vlast - Vltava, that is about a river, and at one point there is something like a storm in the piece with a heavy thunderous bass that is ideal to get a sense of sub-bass impact.
When I want to, as it were, challenge the IEMs with something really technical I will use Brahms' Symphony No 4, which is very complex, very layered and can easily sound disjointed if there is no cohesion.
For vocals I love using Mozart's Requiem and Missa Solemnis by Beethoven. At least as far as classical music is concerned, as I listen to a lot of other music as well of course.
If you are looking for a cheap way to get lots of 24-bit classical music I can highly recommend the Musopen Project. They have a huge 7GB file of classical music for free (open source) and it has several of the pieces I mentioned, such as Eroica, Ma Vlast and Brahms' 4th.
