i recently visited a friend in rhode island who shares my audio interests. while i was at his home, i participated in his auditioning nordost quatrofil ic's as possible replacements for his spm. he has only a single pair of ic's in his system, running between an accuphase dp-75v directly to a rowland model 10. (BTW, we both have avalon eidolons, so i'm quite familiar with the speakers that were being used.) the balanced spm was compared to both balanced and single-ended quatrofil. both pairs of quatrofil were superior to the spm. the single-ended quatrofil, in this system, sounded better than the balanced quatrofil. to my ears the quatrofil is more detailed than the spm, without being clinical or sterile. bass extension and control was also improved, as was the apprent depth of the soundstage. the most noticable difference between the spm and quatrofil was in the all-important mid-range. voices were better resolved, allowing clear placement and definition of each singer in a multi-voice recording, such as the corrs "unplugged." the spm is very fine in my view but, in the system i was hearing, the quatrofil was better. is the quatrofil worth the price differential over the spm? that, only you can decide. i would suggest you look for used product on audiogon; it shows up with some frequency. good hunting. -kelly
