From: Rob Danielson <>
>
>
> I did a quick, subjective comparison of the 744T's pre and the MP2's
> this morning. The mp2's signal is compromised by the additional line
> out and in transformers in its path. Some difference can also be
> attributed to the mics. I wanted to use some matched mkh's for this
> but my mbho603/100D omni mics (14dBA self noise) will have to do. Rob
> D.
I'm not sure about your conclusion on the line out/line in. Only if
there is a mismatch between the two pieces of equipment, the 744's own
mic inputs have a line out/line in point going from the pre, even if
it's not brought out as a connector.
In any case, I did the big download and set it up in SparkXL where I can
have a realtime sonogram as well as listening. Spark's sonogram allows
me to click back and forth between right and left while playing for a
seamless transition in the sonogram. Any difference will be obvious in
the moving display. Much better than the spectrum snapshot in Firium at
telling differences.
There was no obvious difference in the sonograms, it was, in fact hard
to spot the transition point switching channels. Biggest small
difference I saw was that very high frequency spike was stronger in the
MP2 side. And the accelerating car in the middle of the piece was also
reproduced slightly better on the MP2 side. Both of those could be mic
positioning.
I did the switch test many times at all the various settings available
for the sonogram and throughout the sample. Same conclusion at all settings=
.
It's also possible you had a very slight difference in gain between the
two channels. Peak indicates the top sound level of the right channel is
0.1 dB higher than the left. That's not a average, but is a indicator.
That agrees with that spike being stronger on the MP2 side.
Listening the MP2 channel also sounded very slightly louder, and maybe
more detail. Again this could be mics.
You might get a more accurate test splitting the output of a single mic,
no matter how you do it two mics are sampling slightly different sound.
My own conclusion just from this sample is there is no difference
between the 744 and MP2 pre's in this piece. They are very closely
matched. It is possible that there could be extremely small differences
that are masked by using two separate mics. But you cannot draw that
conclusion from this sample.
Walt
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