ADAT out 24 bits resolution?

Satosh · Post by **Satosh** » Fri Mar 11, 2005 9:23 am

I have successfully connected my pulsar II to a rme digiface via optical adat. The rme is connected to a laptop, sx project that is 24 bit 48kHz. I send audio from my scope ("pulsar2 ADAT B Dest") over the optical adat to record on the laptop. The rme is set up as master, scope as slave. Seems to work fine. Nice sound. I'm happy. Easy to setup.

Q: What bit depth is used in the communication? How do I know it is 24 bits?

astroman · Post by **astroman** » Fri Mar 11, 2005 4:38 pm

there should be a software called 'Digitool' or something like that, supplied with the RME.
Not only does it tell you the data format, but also the quality of the connection (jitter, errors etc) - it was always mentioned as a real big bonus in reviews.

cheers, tom

valis · Post by **valis** » Sat Mar 12, 2005 8:53 am

Everything is now included in the RME utility Digicheck: http://www.rme-audio.com/download/digicheck43.zip

In the top bar choose "Channel Status Display" and "Bit Statistics & Noise" under the Function menu. Also check out the Totalyser functions: http://www.rme-audio.com/english/digich ... alyser.htm

valis · Post by **valis** » Sat Mar 12, 2005 10:39 am

Btw, I use Digicheck constantly.

I use the "Stereo Level Meter" for watching my levels as I mix, I've got it calibrated for -14db reference point (which means that peak is +14db). In "Stereo level meter" mode your solid bar is the RMS level, and peak values are shown only with a single pixel high 'hold' indicator. This way I can still watch for overs but I'm more focused on mixing with the RMS in mind. Not perfect but it does help avoid my tendency to push faders up & up & up...

The Goniometer is also great. Using it I can detect fairly minor phase shifts when using mono source and correct accordingly (often necessary when mixing drums & sub in mono through a stereo bus on my analog board etc).

Satosh · Post by **Satosh** » Sat Mar 12, 2005 7:11 pm

Hi! Thanks a lot for the links. I played around a little with digicheck and think I concluded the communication is 24 bits. The markings in "Bit Statistics & Noise" become green all the way up to and including 24 on the bit-row on any channel that is connected to something in scope (pulsar adat dest). Nice. I guess the LSB and AUX would be blue if the signal were 16 bits?

valis · Post by **valis** » Sun Mar 13, 2005 7:15 am

Yep. From the help:

Bit Statistic & Noise

This menu item brings up a function displaying the current state of all bits in the digital data stream, and to perform a DC- and A-weighted analyzis. Erros in the digital datastream and signal to noise ratio (SNR) unweighted and A-weighted can be checked easily.

The Bit Statistic display starts on the left with the most significant bit (MSB) of the audio data and ends to the right with the lowest significant bit. The following auxiliary bits (AUX) will be also used for audio at word lengths above 20 bit. Additional the Channel Status bit (C), the User bit (U) and the Validity bit (V) are shown.

A non changing bit will be shown in its current state (0 oder 1). When a bit changes within 100ms the symbol ‘*’ is shown for every alternating bit.

The background colour equals the meaning of the bits. Alternating audio bits are shown green (normal, bit used), otherwise blue (permanent 0, bit not used). In case of permanent 1 (error or DC) the colour changes to red. The normal state of the Channel Status bit and the Validity bit is green, permanent values (red) indicate an error or distorted audio data.

Bit Statistics enable the user to verify the real used word length, as used bits are always alternating. Additionally it is possible to detect hanging bits (error state, should be alternating).