A Confused streaming system - Mutec / SOtM Ultra

[Confused]

Something comes to my mind here: it's very easy to get hung up about a particular aspect of your system's sound, and become super-sensitive about it.  Meaning that you get into a frame of mind in which it's hard to listen without hearing the very thing you're listening for.  As part of your series of experiments, @Confused, are you able to make some objective measurements of frequency response to determine whether there is any measurable difference between the SOtM and mR?  That would be an interesting thing to know for sure.  Simply finding that there is no measurable difference -- if that's the outcome -- might make it go away subjectively, too.

I do agree, this was exactly what I was referring to with my car rattle analogy.  That said, there is most defiantly a shift in the perceived tonal balance, it is too big to ignore.  I did have a visitor last weekend, when they arrived I was playing something, I can't remember what exactly, and they actually commented with something along the lines of 'that sounds a bit grindy' (non-audiophile speak) So not imagined I think.  (this sounds like one of those user reviews:  my wife was in the kitchen, and without knowing that that I had changed the cable she came into the room and asked 'have you bought a new hifi dear, that sounds amazing') 

As for objective measurements, I did actually attempt this last weekend.  I had a collection of test tones at various frequencies, and was armed with both an iPhone with Decibel X app and a professional sound pressure test meter that I managed to borrow from work.  The idea was to keep the amp at a set fixed volume, test meter in the listening position, run through the tones and check the SPL.  This could then be repeated with the mR in the system.  This almost worked.  The problem was that you could do the test, then repeat it immediately afterwards with no change to the kit whatsoever, and get slightly different readings.  For this to produce a valid result, it would need to be repeatable to within 1 dB, but this seamed to be impossible.  Even the professional meter seamed to behave very oddly with test tones.  It might be reading 75dB, and just walking behind the meter would cause the reading to move maybe 3 dB, walk away and it would hold the reading at the changed level, most peculiar!  Interestingly, the iPhone Decibel X app displayed similar behaviour.  So the final data lacked proper integrity, it did hint at the mR being slightly 'darker', but I knew that the accuracy was not good enough and I might be reading the results with a degree of bias.  What I would really like to do is some REW curves, but I do not believe this is possible via the mR or SOtM kit.  If it is possible, could someone tell me how!

I did think of trying the above test again, with the test meter maybe 4" from the tweeter, but I suspect the accuracy will still not be good enough, and this also becomes a less relevant test.  Another thought is to use REW just as an SPL meter with my UMIK-1 microphone.  Maybe I will try this again if I am in the mood.  Generating an REW curve would be much better though.

Oh, and a final note to @octaviars, I would refer you to my comment in post #79 "This weekend I will commence step 1.  Code name "operation listen to lots of music."