The Focal Spirit Professional is quite warm and dark; not even close to neutral, and certainly not bright. (I owned it twice.)
Click here to see compensation curves superimposed over the InnerFidelity measurements. The green line is my neutral reference for headphones, the diffuse field curve. (Just about all planar magnetic headphones follow this curve in the bass, and they are nearly universally regarded as having the most neutral bass. This curve is also the one most high-end headphones generally follow.) Notice how the bass follows the black line (Harman curve) instead. This is considerably more bass than neutral. (And yes, I know what accurate sounds like, as an experienced musician and audiophile.) Once you get into the higher frequencies, it's obvious that it's rolled-off to an extreme extent. That spot between 3 and 4 kHz where it isn't rolled off can create the illusion of there being a peak there, but it's only that way because practically all the other high frequencies are far lower in volume than they should be.
This can be fixed with EQ, but that can only do so much to help the sound. It also has serious build quality issues (the headband can literally break) and is uncomfortable. The pads are pretty small. The only reason it's over-ear for me is because, like I mentioned, my ears are on the smaller side. Many others have reported it being on-ear for them. You can't easily swap or replace the pads, and the drivers are smaller so they don't facilitate this either.
The Audeze SINE sounds much better than the Spirit Pro regardless of EQ and I don't know of any build quality issues.
