On making small in ear headphones listenable, eg Sennheiser CX80s mod

At your risk. Please play headphones at a low level to protect your precious hearing. This is an atempt to make inexpensive in ear headphones sound close to the amazing reference Sennheiser HD-580. The small in ear headphones sound very treble heavy and bass light compared to the reference HD-580. Using experience on making full range speakers sound listenable by adding an inductor in series (to cut high frequency heaviness, see previous posts), the same was tried on the small headphones. But how to do it simply without really modifying them or using extra cables etc. A very high inductance index nanocrystaline toroidal core was found around Pleiades lab. It is the Magnetec M-059-03F6. It was decided to pass the headphone cable trough it as many times needed, after each time listening and comparing with HD-580. Almost unexpectably everytime after each turn high frequencies were decreasing. 10 turns was the maximum possible because then it is almost imposible to reinsert the mini plug due to space taken up in the hole of the toroid from the cable turns. Now treble seems just a bit higher than HD-580 while bass has become bigger and deeper (due to less high frequency prominance). No chance yet to compare with stock CX80s. It is a joy listening on Sony CD Walkman on public transport, beach, or in the library while writting this to the song Cherish - Kool and the Gang. i Cherish this CD walkman given by my aunt Didi (now a planet Aphrodite, Venus) at some difficult part of life. It immediately made life shine with Sennheiser HD-580.