Great Question.
My short answer would have to be one that consistently
a) puts a huge smile your face
b) makes you shake your head in awe and admiration
c) encourages - no, dares you to keep turning it up (i.e. it's extremely non fatiguing) &
d) above all, one that makes you forget that you're actually listening to speakers
My long answer would be this long winded email that I sent to recording engineer Dave Moulton in 2006 who was involved in the design of the Beo Lab 5 speaker:
Hi Dave,
I just wanted to share my experiences of hearing the BeoLab 5 at the Montreal Sound Show earlier this year.
I was going down the escalator to leave after spending a good 7 hours going to all the various rooms when I heard live music on the mezzanine. The strange thing was, I couldn't see any musicians. So, tired and hungry as I was, I decided to investigate. Enter the BeoLab 5 and needless to say, I was shocked to find out that it wasn't live music but for all intents and purposes it may as well have been - and this, from a company that in my mind, was firmly entrenched in the "lifestyles crap" category!
I have zero audiophile or audio engineering credentials except for arguably the most important two: I listen without prejudice and I know good sound when I hear it and what I was hearing was by far the best reproduced sound I had ever heard. As hungry & tired as I was, I ended up staying there about 2 more hours - I simply couldn't leave. I even enjoyed listening to what I perceived as shitty songs and I am generally extremely intolerant of shitty music (it is for that reason that I can't stand listening to radio but I digress). On 2 separate occasions I got up to leave however, both times I was compelled to return before I made it out the front door - such was the beauty of the sound I was hearing.
All this to say, congratulations for being a part of the design team for such a staggeringly revolutionary product. As amazing as it is to listen to the music that comes out of it, it must be even more gratifying to listen to it knowing that you played a part in it's r & d.
God Bless,
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An unfortunate characteristic of a truly great audio system is that makes you very dissatisfied with your present gear if said gear isn't in the same league!
Since that fateful day on which I heard the Beolab 5, I rarely sit and listen to my own system any more, it's mostly just background listening. Before that, I had never heard a system at any price that made me feel like I was missing much at moderate volumes compared to my little B60 DAC and PSB Silvers.
On the other hand, a positive thing about hearing a truly great sound system is that it makes you realize just how laughably insignificant things like cables, dacs. amps and preamps are compared to the recording quality and to state of the art, boxless and active speakers like the BeoLab 5s and the Linkwitz Orions.
Every music lover owes it to themself to listen to music through these speakers.