On Thursday, August 8, 2013 3:09:18 PM UTC-7, Bob Lombard wrote:
On 8/8/2013 3:05 PM, ScottW wrote:
Here you go.
http://cdn.rohde-schwarz.com/dl_down...r_Manual_e.pdf
This is the user manual for Rohde & Schwarz UPV Audio Analyzer. This
is not a toy. It's a professional tool for designers and production
test. Pick a test and you will find that the system has a factory
programmed source specifically optimized for that test to provide the
highest accuracy and speed possible for that test. While the system
can use pre-recorded signals including music for some tests (not all),
I think you'll find that for any parametric tests you've listed above,
the extremely low noise precision signal generators are used.
In fact the accuracy and repeatability can be pretty much equal.
Virtually every piece of test equipment improves it's accuracy and
repeatability by averaging. Non-repetitive music samples do not lend themselves
to this and for measurements like THD+N (ref pg 130)..you will note that
"sinusoidal signals are required".
ScottW
Scott, please forgive (or at least ignore) my ignorance. How do these
tests /directly/ relate to the accurate reproduction of music - assuming
that a microphone is a requirement for capturing it, so starting from there?
bl
It doesn't relate to the accurate reproduction of music. It relates to
the accurate transfer of audio signals. Those are not the same thing.
If we are talking live acoustic music then the original 3 dimensional
soundfield is out of reach and no recording and playback system even
tries to accurately reproduce it. It's just not how audio works.
Audio, in the case of high end audio and acoustic music that was
originally performed on acoustic instruments in a real space is more
about creating an aural illusion of the original event from a chosen
listener perspective. Some believe that accuracy from the source
signal (the CD, SACD,LP etc) to the speaker terminals is important in
achieving that aural illusion. others like myself don't believe there
is always such a correlation and in some instances certain distortions
to that signal will enhance the aural illusion of realism.