Your test makes sense and show what I expected.
At 18:04 2005-06-20, you wrote:
>I just made a quick comparison between the new Marantz PMD 671 (that is
>capable of recording at 24bit/96kHz) and the SoundDevices 722 recorders in
>conjunction with a pair of Rhode NT1-A microphones (sensitivity: 25 mV/Pa,
>equivalent noise: 5dBA).
>Inspired by Rob Danielson's test arrangement, I placed the two microphones
>on the desk in my office (microphone spacing about 10 inches). There was a
>ticking alarm clock at a distance of about one meter and a small tweeter
>producing a constant reference tone of 1 kHz.
>I first recorded the reference tone. I then switched the speaker off and
>subsequently replaced the left microphone by a resistor of 180 ohms
>connected to the pins 2 and 3 of the XLR connector (and additionally two 6k8
>resistors between pins 1 - 2 and 1 - 3 in order to draw a current from the
>phantom power supply circuit). I did this procedure with both recorders
>under exactly the same conditions. Unfortunately, there was some additional
>ambient noise (hum and distant jets).
>The recording settings were as follows:
>- sample rate: 44.1 kHz
>- bit depth: 16 bit (dithering enabled on the SD722)
>- approximate recording level of the 1 kHz reference tone on both recorders:
>- gain setting on the PMD 671 : 5
>- gain setting on the SD722 : 68
>- no high-pass filtering selected on the mic pre-amps
>Except of some cutting, I did not change the original sound files:
>To me, the differences are very small. The dummy resistor test section
>reveals the lower inherent noise floor of the 722 preamps. However, as Klas
>already mentioned, when using such high-output microphones, these
>differences should become nearly irrelevant.
>The most important difference is perhaps the higher (hard-wired) cutoff
>frequency of the PMD 671 preamp, which might reject a portion of the bass
>components that might be useful for a "spacy" sound. I don't know how the
>new PMD 671 exactly compares to the PMD 670 (the MIC Signal-to-Noise Ratio
>specification on the Marantz website is 65 dB for both models).
>Nevertheless, it makes much more fun to use the more professional
>SoundDevices recorder (high-quality metal housing, very nice battery
>powering concept, large internal harddisk, ...).
>Weitersagen: GMX DSL-Flatrates mit Tempo-Garantie!
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>"Microphones are not ears,
>Loudspeakers are not birds,
>A listening room is not nature."
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