I checked the
Oade mod page for the R44.
I am in no doubt that the internal mic-pres can be improved - from a random-noise/hiss perspective. For example, if I want to do any quietude recording with the R44 I need to use a MixPre in front of it. I previously posted the following recording, 10 ticks R44 max gain, then 10 ticks MixPre set to match this gain and the R44 at minimum gain to compensate, NT1-A mic...
Click here to download WAV file (3 Meg)Noise of R44 vs MixPre mic preampsHowever Doug at Oade notes on his site that there is 'display-noise'? ...
"Edirol R44 Concert upgrade rebuilds the mic preamps using high speed,low noise and very low distortion op amps that dramatically improve detail and clarity. Improvements are also made to reduce the
audible digital noise that contaminates the analog signal path with noise generated by the display."
...as I previously posted, I looked/listened carefully for any digital noise and couldn't find any:
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OK, here is a Rode NT4 sitting in a vocal booth connected to an Edirol R44 running all but flat-out on the internal preamps...
R44 on internal batteries.
Chanels 1 & 2.
Phantom on.
Low-cut off.
Limiter off.
Display on (default brightness).
Preamp sensitivity (max) = -56 dB
Level = 12 O'Clock
24 bit @ 44.1 kHz
Here is the sound <- Click here to download the 10 second sample
IMO those are some beautiful looking noise graphs from a digi-noise perspective. Not a spike anywhere, only hiss and some low frequency rumble (very low level and recorded not digital). The same is true when you normalize or add any level of amplification to the digital recording. I would be genuinely interested to know what Doug is hearing?
In case you are wondering what digital noise may look like, in my experience, digital noise usually appears as spikes in frequency histograms or lines in spectrograms...see this R09 plot picture
or even more dramatically, here's device-to-device interference (digital camera on R09)
digifish