Topic: RME UFX preamp level too hot?

Hi
Am i happy user of the RME UFX, briiliant product.
I am using adat an analouge inputs on the back for my outboard pre´s.
I tried the the mic pres on the front today using Sontronics DM1 condenser mics. These mics has a -10db pad.

when plugged in to the front i found that the lowest level of the UFX mic pres are 10db or 0db.
Is there no miclevel between 0 and 10db?

regards
Birger

2

Re: RME UFX preamp level too hot?

No. Please read the manual.

Regards
Matthias Carstens
RME

Re: RME UFX preamp level too hot?

I have the same concern... why can't the UFX be adjusted in the 0-10db range in 1db increments? The first test I did with the UFX was to record some drums.

I used a Shure 57a Beta on snare (industry standard mic for a snare drum).

Result:
0db too quiet - only just going in to yellow at full pelt on the drums.
+10db is too loud - giving occasional clipping.

8db would be perfect, why is there no 8db???

The only reference I could find in the manual (with no explanation, which is ambiguous at best, misleading and doesn't mention the first 10db of the mic pre stage being unusable!!) was this:

"The four balanced microphone inputs of the Fireface UFX offer a digitally controlled gain of 0 to
65 dB via XLR/TRS combo jacks. The gain range is 65 dB, adjustable in 1 dB-steps over a range
of 55 dB. The soft switching, hi-current Phantom power (48 Volt), switchable per channel,
provides a professional handling of condensor mics. Up to a level of +12 dBu, the front XLR
input can also be used as Line input."

So what is the reason? Can it be rectified?

Re: RME UFX preamp level too hot?

If 10 dB is too hot, then 0 dB can not be "too quiet". There is no reason to worry about a signal that is 8 or even 10 dB below full scale, it can easily be normalized digitally later.


Regards
Daniel Fuchs
RME

Regards
Daniel Fuchs
RME

Re: RME UFX preamp level too hot?

Twan52 wrote:

So what is the reason? Can it be rectified?

It is because the IC pre-amp (Texas Instruments PGA2500*) used in the front end is designed that way.  Its gain can varied by digital control in 1dB steps between 10 and 65dB.  It also has a separate control to set it to unity gain (0dB).  Thus there is no provision to set a gain value between 0dB and 10 dB.

So if you need further explanation, you should talk to Texas Instruments. And I endorse Daniel's remarks - the performance at either 10dB or 0dB gain is such that recording 10dB low would not have a noticeable impact on noise and distortion.  (And would you run the snare at 0dBfs in the mix anyway?)

(*BTW, the BabyFace uses a cheaper version of the above chip - it has a range of gain adjustment of either 0dB or 9dB to 60dB in 3dB steps.)

De gustibus - et sonus - non est disputandum

Re: RME UFX preamp level too hot?

RME Support wrote:

If 10 dB is too hot, then 0 dB can not be "too quiet". There is no reason to worry about a signal that is 8 or even 10 dB below full scale, it can easily be normalized digitally later.

By that rational there is no point in the mic pre's doing +1db increments at all!? Why not just make the whole stage go up in 10db? (0,10,20,30,40,50,60,(65?)) That doesn't sound right to me...

panatrope wrote:

(And would you run the snare at 0dBfs in the mix anyway?)

Nope. In the example I gave the snare showed up at < 0.5db over when I flammed it at full pelt. So I have no choice but to allow for 9.5db of headroom for a reason that was unexplained.

If it is a limitation of the preamps then discussion over - I just don't believe that an extra bit of res can't be squeezed out with an 8db boost when recording @ 44.1k if a drummer has a more tender moment on the snare (as one example).

Re: RME UFX preamp level too hot?

Twan52 wrote:

If it is a limitation of the preamps then discussion over - I just don't believe that an extra bit of res can't be squeezed out with an 8db boost when recording @ 44.1k if a drummer has a more tender moment on the snare (as one example).

There really is no point. If you're concerned about bit resolution, don't be. And I don't know of any mic preamps that has a broader gain range than 55 dB. So usually, if you need less than 15-20 dB's of gain, you must pad the signal and up the gain. What you do with the UFX is "pad" to no gain and up it in software instead. You do not lose any resolution or performance. 24 bits have headroom to spare and beyond...

Re: RME UFX preamp level too hot?

Shooting for -8dBfs peaks at the ADC on a live drum track is PLENTY hot IMO!  I generally aim lower than that.  Nothing to worry about - and you might be pleasantly surprised with your results when using more conservative levels at your ADC...

cool

MADIface-XT+ARC / 3x HDSP MADI / ADI648
2x SSL Alphalink MADI AX
2x Multiface / 2x Digiface /2x ADI8

Re: RME UFX preamp level too hot?

Thanks for replies... mind is set at ease. It is just a bit weird for me not to be able to fine tune the mic gain in this region.

I found this article which supports your comments: Headroom (Soundonsound)

Happy recording!