The FX 55's are strange in that they have a really big soundstage. I have AKG K401's so I know a decent soundstage. The JVC's replaced my Koss(more fun, some isolation, and made them sound small) as my main portable phone. I also tried the Audio-Technica CK5's based on their great reviews and the fx-55's beat them too. For even less than $15, some isolation/no leakage, and also a volume control version available they, IMO, take the title of "king of the budget cans" away from the Koss models.
They do need a small clip for the cord. The good seal and light cord make them microphonic. Hooked to right below where the cord splits and the only real drawback to these phones is removed. The other drawback is that they do not come with any sort of case/bag to put them in.
I don't know which Lyra you have. I have the RD2765 5GB. The JVC's sound very good with it. They beat the Koss even though they had great synergy with the Lyra. The RD2675 came with Sennheiser MX-400's, decent buds, which the JVC's also beat.
They JVC's as well as the Koss have a lot of bass. The JVC sounds less congested basswise, a little more defined to me. Actually, the JVC's have more bass since I don't use the Jazz preset which was what the Koss had the magic synergy with. It raises both the bass and treble. There is too much bass with the JVC so I can't use it. I use the 5-band and boost only the treble to balance the bass since I am not much of a basshead. Basswise, they are like the DT770 of the canalphone world.
Anyway, if you froogle them, they can be had for as low as $20 shipped. I paid $22 shipped.
I'll also add that while people have had problems with HJE50's and EX51/71's breaking, I have had more than a few times where the JVC's have been yanked out of my ear/s with falling players, tossed them around and let them get tangled etc. yet no problems in the 3-4 months I've had them. I like that they come with a 1 year(not 90-day) warranty and JVC America is in Wayne, New Jersey so if there is a problem(I'm in NY) postage is cheap for me.