Both D1 and D50 have two A/Ds (AK5358s in D50). Right after the usual analog input stages, the signal is split into two paths, both running their own A/D stages, one set for normal recording levels, one running 20dB lower. System controller selects the appropriate line to be committed into memory according to limiter settings.
It's hard to see the utility of that system - the problem that remains when recording using 24 bits is not digital clipping but analog clipping. I'm not saying it doesn't work (in typical scenarios) but I don't see how it can!
Hmmm. I don't have all the details exactly, as I don't have the service manuals myself...just two little pieces of schemas. Anyways, as far as I can tell..and what I was trying to tell is that the input limiting is "built in" at analog stages in D50, right in front of the ADs.
Nothing but external limiter in front of the recorder would prevent clipping the input stages if you'd have strong enough source. Next option would have something built into pre-amp stages like here, in a way. And the last, manipulating the already digitalized signal, which is kinda moot. Right?
This sounds misleading. The D50 does not 'switch depending on limiter settings'.
It simply digitizes TWO signals. One 20db down (or is it 12db, im not sure atm).
Both are digitized into some buffer memory. Normally, the 'normal level' AD is written to card memory.
Once the normal input get overloaded, the processor *replaces* the previous x seconds (depending on limiter speed settings) of what gets written to card with the signal from AD 2, or more precise, with whats in the temporary memory buffer of AD2 (which records 20db down from normal level). Crossfading is used at the start/end of the little snippet, and the -20db recorded snippet is also normalized of course, to keep the level difference as low as possible.
Really quite simple actually, and very useful.
It does indeed sound like the M10 does something different - something less 'costly' to produce i guess, one DA etc..
Oh and , concerning the M10, has anyone done a comparison to the D50 yet ??
I'd be very interested how it compares, specially noise-level wise...
Cheers
Oh and hi everybody. Just signed up. Been a field recorder for a long time, first with MDs, then R09 and nowadays with a D50 - internal mics and okm.