Need Help - NAGRA VI

[supoUSA]

I've called AKG - they didn't know. I called Nagra (which I'm not impressed at all because they have a person that fixes the machine and he prefaced the conversation saying - "I'm like an airplane mechanic - I can fix it but I don't know how to operate it". NAGRA is 2 strikes down in this regard for my purchase between a SD (always there) and this unit.

I'm not engineering knowledgable - I'm learning - but surely the manufacturers of the mics or the recorder should have answered that - and my question is this:

It's asking me on the preamp menu - what setting do I want - 2.8mv/Pa or 10mv/Pa. Then, it has a mic scaling menue where I can select 1 - 50 mv/Pa. Nagra assumes you've been breastfed on Nagra and so their user manual is not a user manual - it just tells you what this and that is and it's not an operational manual.

So - here is my mics (the AKG 480B) with the CK61 capsule. I'm recording an orchestra. Do I set the preamp to 2.8 or 10mv/pa? And on the mic scaling - what do I set the unit to?

Here's the specs of my mic. I planned on padding the mic -10 because I have no idea how load the group will get:

http://www.akg.com/mediendatenbank2/...5c282bda80.pdf

I'm leaving at 7:00am tomorrow for this recording and will be unavailable. Hopefully there are some people laying around on a Fri nite to help me with this situation.

[boojum]

If NAGRA is unable to help I am sure some one of the NAGRA VI owners on the board can bail you out. Good luck. We are all looking forward to the test.

I had no idea these boxes were inscrutable.

[summer_room]

I have no technical knowledge, but a quick google search got this result:

Microphone sensitivity and conversion - microphone transfer factor mV/Pa to sensitivity dB re dB re 1 V/Pa or dyne/cm2 microbar pascal pascals microphones 0 dB dBm mV mic sensibility calculation microphone resistance calculation - sengpielaudio Sengp

-jon

[Larry Elliott]

Originally Posted by supoUSA

It's asking me on the preamp menu - what setting do I want - 2.8mv/Pa or 10mv/Pa. Then, it has a mic scaling menue where I can select 1 - 50 mv/Pa. Nagra assumes you've been breastfed on Nagra and so their user manual is not a user manual - it just tells you what this and that is and it's not an operational manual.

I regularly use a Nagra VI for Orchestral Recordings - with DPA rather that AKG mic. I always use 10mv/Pa. Assign the Potentiometers to Mic Inputs and adjust the level until you get suitable levels of the level meter - typically peaking at about -10dBFS.

Hope this helps.

Regards
Larry

[John Willett]

Originally Posted by supoUSA

Nagra assumes you've been breastfed on Nagra and so their user manual is not a user manual - it just tells you what this and that is and it's not an operational manual.

Larry Elliott has answered your question.

But I do disagree about the manual - the Nagra VI was my first Nagra and I found the User Manual excellent.

By the way - you mention you are leaving at 7:00AM, but give no indication of what timezone in the world you are in!

[didier.brest]

So what is the reason why there is a mic scaling menue in addition to both preamp sensitivities ?

[Plush]

Please read the manual again with the NVI machine in front of you. It does tell you how to set each setting.

However, since terminology and menu names change with software updates, make sure you are looking at the current manual for your software release.

Most of the time setting 10mv/Pa corresponds to the old "condensor" mic setting. The 2.8mv/Pa setting is for dynamic mics.

Other settings to check include:
assignment of outputs
what channels will be recorded?
phantom on and off
limiter on and off
how the machine is set to back up to the CF card and which channels will be backed up? (set to auto and select all channels)
clock settings correct?

It's really just using the machine for a while that gets you familiar with its functions.
GS is your best resource for info in the USA.

[meltemi]

The noise figures of the AKG 480B are lowest, when the attenuator on the mic is
left at 0dB, according to the specs published by AKG.
The sensitivity of the mic is then 20mV/Pa.

I assume, you have two mics for a stereo recording

In the Nagra VI Settings/Audio settings/Inputs menu set
Mic 10mV/Pa (Cond) on tracks 1 & 2
Activate 48V (phantom power) for both mics
Activate REC (arm tracks) on tracks 1 & 2

Return to the main screen,
Set the Nagra VI to Test
and turn pots 1 & 2 partly clockwise;
the signal picked up by the mics should now be shown on the meters.

By Setting the Nagra VI to Rec, you are up and going.
Adjust the recording level with the pots

Additional Tips:

In the Nagra VI Settings/Audio settings/Mic display scale menu set
Mic 1 and Mic 2 to 20mV/Pa
This gives you a direct indication of the SPL (Sound Pressure Level) according to the settings of the pots, but does not affect the record level in any way.

For Stereo you can use a single pot to control both mics.

In the Nagra VI Settings/Pot. assignement menu do the following
For Pot 1 select MIC and activate tracks 1 & 2

If the mic calibration charts delivered by AKG with the mics show a difference in
sensitivity (mV/Pa), calculate this difference into dB by using the formula
20*log (sensitivity mic 1/sensitivity mic2).
If the resulting number has a positive sign, then mic 1 is louder than mic 2; if the resulting number has a negative sign, then mic 2 ist louder than mic 1.

In the Nagra VI Settings/Pot. assignement menu select the white triangle at the end of the line of Pot 1 and press Enter to access
the offset compensation menu page
If mic 1 is louder, attenuate mic 1 in -0.1dB steps by pressing the Down button
If mic 2 is louder, attenuate mic 2 in -0.1dB steps by pressing the Down button
Alternatively
If mic 1 is louder, increase mic 2 level in +0.1dB steps by pressing the Up button
If mic 2 is louder, increase mic 1 level in +0.1dB steps by pressing the Up button

You can now control the record level of both mics with the single Pot 1 and the
sensitivity levels of both mics are matched within 0.1dB

Neither Nagra nor AKG are to be blamed for not answering your questions, as
these should rather be categorized as "How to do a recording" (sorry).
All necessary parameters are available from the Nagra VI User Manual and the
specs and calibration chart of your AKG's.