1 Topic by panatrope (edited by panatrope 2013-02-24 05:02:00)

  • From: Melbourne, Australia
  • Registered: 2007-05-16
  • Posts: 495

Topic: Dynamic mics with BabyFace

For reasons which some may find hard to understand, I prefer dynamic mics (M88s, EV RE50) for outside broadcast work.  However, for normally interview/presentation work, a re-ampo gain of 70 to 745 dB is need to ensure that the link is fully modulated in these circumstances.  The 60dB max gain of the BabyFace is a bit of a limitation in these circumstances.  I had previously asked MC about a switchable fixed digital gain boost to overcome this.

However, guided by MCs previous remarks about dynamic sections gains (irrelevant to the BabyFace), I had a look at the EQ section.  The HF shelving offers a boost in the selected band of up to 20dB, and the shelving frequency can be set quite low.   Use the turnover frequency set to 100Hz or thereabouts, (acts like the usual voice  hpf set to this frequency, and about 10-12dB boost, set the corresponding output to LoopBack, and there you have your extra gain. No audible impact on quality, and the Ein of the pre-amp at max gain (about -123dBV) means that noise is no worse than it would be, especially boosting the gain further down the chain.

A good trick when it is needed.  Another demo of how versatile the BabyFace can be.

De gustibus - et sonus - non est disputandum
  • TGL
  • AD/DA expert
  • Offline
  • Registered: 2012-11-20
  • Posts: 59

Re: Dynamic mics with BabyFace

745db?!

  • From: Stockholm, Sweden
  • Registered: 2007-10-22
  • Posts: 84

Re: Dynamic mics with BabyFace

TGL wrote:

745db?!

Very much needed for recording gnat farts :-)

Mats Helgesson
http://www.livingsound.se

MatsHelgesson's Website

4 Reply by panatrope (edited by panatrope 2013-02-24 22:36:35)

  • From: Melbourne, Australia
  • Registered: 2007-05-16
  • Posts: 495

Re: Dynamic mics with BabyFace

The front end would be overloaded from the noise of Brownian motion of air molecules.  Could be useful for true point source microphones, which of course would have infinitesimal sensitivity.

Let's make that 75dB.  (And I appoint TGL as honorary proofreader.)

However, I do know of one system (which includes RME gear) out there that detects distant acoustic echoes by applying a gain of about 300dB ...

De gustibus - et sonus - non est disputandum
  • Registered: 2011-08-05
  • Posts: 21

Re: Dynamic mics with BabyFace

panatrope, get yourself a cloudlifter CL-1.  It is an easy to use, compact solution for common audio problems faced in the field and in the studio. Designed for all passive microphones – including ribbons- the CL-1 safely uses any standard phantom powered microphone input device to provide up to +25db of ultra-clean, transparent gain.

6 Reply by panatrope (edited by panatrope 2013-02-25 11:17:19)

  • From: Melbourne, Australia
  • Registered: 2007-05-16
  • Posts: 495

Re: Dynamic mics with BabyFace

I have indeed looked at the CL1 and other 'in-line' devices from people such as RODE which provide a phantom powered inline preamp for dynamic mics (such as SM58 or the RODE equivalent M1, but they often have an Ein worse than the effective Ein of the BabyFace (which of course sets the achievable S/N ratio).  The workaround does not need an additional piece of equipment, needing additional power, additional carrying space, etc.  But your supportive remarks about the CL-1 are indeed noted with thanks.

If I really needed additional gain, I would use two channels of my battery-powerable QuadMic, at near maximum gain, into the input of the BabyFace.  Indeed, if I needed more mics in my remote situation, I would arrange a passive mixer to mix the 4 outputs of the QuadMic into the two BabyFace Mic/Line inputs.

That's what I like about the RME product range - how it all integrates so well to make the system you need (well, most of the time, anyway ... :-) )  Hint: a  QuadMic II using the PGA2500, supporting gain adjustable in 1dB steps and accurately resettable would go a long way to eliminating the preceding "most of the time" qualification. Again, :-)

Historical note: I am always looking for a modern equivalent of the well known AWA BAR2A (Broadcast Amplifier Remote - based on an RCA design).  It could provide up to 94dB of gain - nominal input of -80 or -86dBm in, depending on input transformer strapping, up to +8dBm (0VU) out drive a telco line.  Germanium technology, it still boasted an Ein of about -123dBm with 150 ohm input termination.  Workhorse of the Australian broadcast industry.  Would run for hours on 4 9V batteries.  I still preserve mine for special occasions.

De gustibus - et sonus - non est disputandum