Compatibility questions

[brew]

I suggest familiarizing yourself with operating levels and how they work.

The Benchmark ADC16 for instance has +8 dBu to +28 dBu input sensitivity range (at 0 dBFS) which can be configured per input (the manual says something slightly different so you'd have to get them to fix their typo).

Since the output of your XTA transformer is +10 dBu, naturally do the math and you can trim the ADC16 input sensitivity to work with that piece so that it easily clips the ADC16. This is how that works: if the ADC16 is trimmed to produce 0 dBFS with +8 dBu in, then of course +10 dBu from the XTA will also clip the ADC16, by 2 dB. You'll want to keep the default trim on the inputs from the Sytek because that is +24 dBu.

Benchmark describes the operation of the Firewire interface on their website, but I would contact them to see if it will work as you want--daisy chaining two ADC16's.

I see no reason to doubt Avid's statements about how many channels Pro Tools native can record and play back.

[T.O. Ross]

Originally Posted by brew

I suggest familiarizing yourself with operating levels and how they work.

The Benchmark ADC16 for instance has +8 dBu to +28 dBu input sensitivity range (at 0 dBFS) which can be configured per input (the manual says something slightly different so you'd have to get them to fix their typo).

Since the output of your XTA transformer is +10 dBu...

Thank you for the reply.

+10 is the maximum output level rating for the XTA's transformer outputs. Their nominal output level is rated to be -10 dB. Hence my question. It seems to me that it would take a signal that is much hotter than the signal from a mic to coax +10 out of one of the XTA's transformer outputs. If my math is right, a nominal -10 signal from the XTA would yield a signal level of -18 dBFS on the Benchmark side.

Thanks again for your reply.

Cheers,

Ross

[brew]

I suggest that your math reveals a misunderstanding about levels. Max IO level is the only relevant number--nominal level is irrelevant.

1. The ADC16 ships set to 0 dBFS = +24 dBu. This is quite easy then to understand that +10 dBu would equal -14 dBFS.
2. You can alter the ADC16 input level setting to be anything between 0 dBFS = +8 dBu through +29 dBu.
3. If you connect the XTA transformer out (+10 dBu) to the ADC16 input and do nothing to the ADC16 trim levels, in your DAW you will never peak past -14 dBFS. Why is this so? Because 24-10=14.

If my math is right, a nominal -10 signal from the XTA would yield a signal level of -18 dBFS on the Benchmark side.

Your math is not right. The XTA clearly has 20 dB of headroom (max level - nominal level = 20). Using the math from above, 14-20 = -34 dBFS. That's where your nominal signal level would be in the digital domain if you did not alter the cal of the ADC16.

"Nominal" is not a universally agreed upon level, which is why you can ignore it. A manufacturer could choose a different nominal level for their gear, and this is a fine example. The ADC16 ships with a nominal level of +4 dBu, with 20 dB headroom (the well accepted SMPTE standard). The XTA transformer out also has 20 dB headroom, but the nominal is -10 dBu! Clearly nominal in this case is not the same.

Also, your note about mic level is not quite right--the XTA is a preamp, and all the outputs are post preamp. It is not a traditional passive mic splitter, so it would likely be easy to achieve +10 dBu at the output with a microphone.

I hope the attached graph makes it clear.

[T.O. Ross]

Thank you for the graph -- and for your patience. Makes a lot more sense now!

Cheers,

Ross

[nnajar]

reaper for both the stability and lack of ilok. You can drop the files in PT easily for mix later, or j.

[T.O. Ross]

Originally Posted by nnajar

For a location rig, I would suggest reaper for both the stability and lack of ilok. You can drop the files in PT easily for mix later, or just mix in reaper.

Noted -- thank you for the reply. I will look into how Reaper files can be dropped into Pro Tools.

Thanks again,

Ross