• Registered: 2017-07-12
  • Posts: 3

Topic: Mic recording using rear analog inputs

Hello,

I use the RME fireface 802 for audio I/O. I wanted to calibrate my earphones and for that I use a microphone to get the dBs.

First of all I wanted to check the signal from the microphone is correct so I use a 1kHz, 94dB professional sound calibrator. I have done this before using NI-DAQ boad to read the microphone input and I could read the 94dB. However, now that the microphone is connected to the RME soundcard input I dont read 94dB but 69dB. So there is a 25dB input signal reduction that I dont understand where it comes from.

I am not very familiar with TotalMix since I normally do basic I/O operations with matlab or python and I dont need fancy mixing or operations so I tried to keep TotalMixing settings as simple as possible. I reset it, have it in DAW operational Mode and I believe I dont have gains or trims but I am sure there must be something in the configuration that reduces my real signal.

Could someone help me? As you see I am not familiar with sound engineering stuff, but would like to learn! I have been reading things and I guess it could be related to the -18 dBFs line level recording?

Cheers,

Marina

2 Reply by fl

  • fl
  • S/Mux specialist
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  • From: Toronto, Ontario, Canada
  • Registered: 2007-11-12
  • Posts: 266

Re: Mic recording using rear analog inputs

If you are plugging the microphone directly into one of the back panel's inputs, this could explain it. The back panel inputs are designed for Line Level inputs, not Mic Level, so you need a microphone pre-amplifier between the mic and the input, to bring the mic's signal up to line level.

Frank Lockwood
https://LockwoodARS.com
Fireface 800, Firmware 2.77
Drivers: Win10, 3.125; Mac, 3.36

fl's Website

  • ramses
  • DAW Mastermind
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  • From: UTC+1
  • Registered: 2012-10-14
  • Posts: 13,209

Re: Mic recording using rear analog inputs

TotalMix is not that hard if you understand only a few important basics.

This I put together here in my blog: http://www.tonstudio-forum.de/blog/inde … rnal-equi/

RME offers also nice support by providing Youtube Videos:
http://www.tonstudio-forum.de/blog/inde … al-Videos/

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14
  • Registered: 2017-07-12
  • Posts: 3

Re: Mic recording using rear analog inputs

Hello,

thank you very much for your comments.

To fl: the microphone is connected to its preamplifier first and I can control the sensitivity there. When I read the output of this preamplifier with the NI DAQ board and take into account the microphone sensitivity and compute the dB SPL I do get 94 dB, so it is about the RME sound card.

To ramses: thanks for the information. I am going to read your blog now and will have a look at the videos, although what I need is so simple that normally the videos are not relevant for me. But thanks for pointing me to them anyway.

5 Reply by ramses (edited by ramses 2017-07-14 14:24:39)

  • ramses
  • DAW Mastermind
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  • From: UTC+1
  • Registered: 2012-10-14
  • Posts: 13,209

Re: Mic recording using rear analog inputs

marinasaizalia wrote:

Hello,

thank you very much for your comments.

To fl: the microphone is connected to its preamplifier first and I can control the sensitivity there. When I read the output of this preamplifier with the NI DAQ board and take into account the microphone sensitivity and compute the dB SPL I do get 94 dB, so it is about the RME sound card.

To ramses: thanks for the information. I am going to read your blog now and will have a look at the videos, although what I need is so simple that normally the videos are not relevant for me. But thanks for pointing me to them anyway.

Hi Marina,

you're welcome.

The essence of everything is to understand, that TotalMix FX has a very comfortably submix mode.

Basic operation is, that you click to one Hardware Output, then you configure for this particular output, which Hardware Inputs and Software Playback channels shall be routed to this output (by raising or lowering the faders or settings an input or playback channel to mute).

Another principle to understand is, that every signal that enters your recording interface (in TotalMix FX "Hardware Inputs") will always be passed send to the DAW inputs, not matter whether you Mute this channel or not. The Mute of HW Inputs and SW Playback channels has only an effect for the submix (output) in TotalMix.

So in TotalMix you have as many submixes as you have HW outputs (outputs of your recording interface).

To make everything a little bit more easier / more structured, everything starts, that you push "assign" knob in the Control Room Section of TM FX and 1st assign output channels for typically / at least: "Main Out" and "Phones 1".
Then these output channels will be displayed in the Control Room section.
To make a routing for them again you click the output channel and then adjust HW inputs and SW playback channels.

HW Inputs refer to your recording devices input channels
SW Playback channels refer to Windows Applications, to where they send their output signal.

Thats all .. save your work in snapshots and workspaces not to loose it.

Then configure additionally in the TM FC Preferences to always init DSP devices with TM FX settings, then you do not become asked on every boot, whether you want to choose device or TM FX settings to initialize your device for operation.

A complete little "walkthrough" in my blog.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14
  • Registered: 2017-07-12
  • Posts: 3

Re: Mic recording using rear analog inputs

Thank you ramses. I see much clear how TotalMix FX works now. Although I still dont understand why when reading the microphone signal (after being preamplified) using the analog input in the RME I get a reduced signal, compared to the signal I record using a an analog input in the DAQ NI board.

  • vinark
  • DAW Mastermind
  • Online
  • Registered: 2009-06-05
  • Posts: 2,779

Re: Mic recording using rear analog inputs

The inputs have 3 basic gain settings. lo gain, +4 and -10. It is probably at lo, so try +4 or -10 for the best match to your preamp.
Cheers

Vincent, Amsterdam
https://soundcloud.com/thesecretworld
BFpro fs, 2X HDSP9652 ADI-8AE, 2X HDSP9632
  • ramses
  • DAW Mastermind
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  • From: UTC+1
  • Registered: 2012-10-14
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Re: Mic recording using rear analog inputs

Click the "tool symbol" in TM FX under the Hardware Input Channel, where your Mic is connected to ..

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub14