Do ixos cables need burn in time?

Have been using the IXOS GAMMA 6003 speaker cable for the last 6 months and I have a few observations:
1. The sound will round out over a month or so.
2. The sound improvement is equipment dependent. My main music system is composed of: ADCOM AMP/PREAMP/TUNER circa 1990; SONY 555 SACD Player; AR-302 speakers; and IXOS Silver Series audio cables and the sound is very layered, warm and musical. My AV system is a DENON 2802 Receiver; SONY 560 DVD Player; SONY ES-XA1 CD PLAYER; AR-302 speakers; IXOS Silver series audio and IXOS GAMMA 6003 speaker cable. DVD movie & music sound is fairly good, but CD music sound is fairly uninvolving. I know that the CD player may be at fault or I have become accustomed to separates, but the cables are a wash in this system.

Hope this helps.

What about the highs don't you like?? At $1.49 per foot, it is kind of hard to fault this cable. I've demo'd it and found it a big improvement over generic (monster type) cable which is the only thing cheaper. How is the 6003 terminated (What kind of ends)??

I would tread slowly here. Compared to generic cable the 6003 is more revealing. It could possibly be telling you about something else in your system is off in the highs (CD, Amp, other interconnect cables, etc).

What is the rest of your system composed of? Going further up the ladder is only going to make things more revealing. All cables need some burn-in. I still use the 6003 in a high-end receiver based system in my work office.