Don`t agree at all. With better cable and good matching source gear X1 can be quite close to neutral sound signature.
Yes, it still has littlebit more bass than analytical cans but in a good way - it makes sound natural and never overpowers other frequencies or bleeds into mids.
I don't mean to be "that guy" but just look at the response curves. The X1 is not only bassy, but it's notoriously bassy, intentionally bassy, and praised for being bassy. No, it is not neutral and will not be neutral unless you EQ it. Tyll nailed it in his review:
Bassheads will melt in their own pool of love for the X1; it's a great basshead can.
Most big-bass headphones have problems with their coloration. Add a bunch of bass, and the stuff in the mid-range often suffers from lack of attention. Even the V-Moda M-100---a basshead can I really like---has dips and peaks in its frequency response that let some things get lost in translation. Most basshead cans are sealed, which allows designers to get good extension into the low frequencies, but sealed cans sound closed-in and usually lack the airy, spacious sound of open headphones. The Philips Fidelio X1 doesn't seem to suffer from these problems.
I never said it was BAD or overpowering, just that it's a very bassy headphone. Especially if you stack it against the rather sterile HD600's which the other poster was asking about.
Keep in mind, I owned both the X1 and the HD600, take a look at my sig to see which I kept.