Topic: Wrong Input Level Fireface 800

I have imported into Sonar a wav file from 44.1k and 24bit with a sine wave of 1000 Hz @ -1.0,
the playback and the output in Fireface mixer are correct, i have connected analog input 1 and
output 1 in loop-back with a balanced cable, but the Fireface mixer measure to input 1 -1.53,
why not -1.0 ??

[img align=L]http://www.bonisaudio.com/level.jpg[/img]

www.bonisaudio.com

2

Re: Wrong Input Level Fireface 800

Because both input and output stages have a small intentional offset to prevent overload. If in your example both levels would be set to match 100%, and the usual deviation during manufacturing causes a positive offset of only 0.1 dB, you would get overloads already. So better loose a little bit and stay on the safe side.

Regards
Matthias Carstens
RME

Re: Wrong Input Level Fireface 800

MC wrote:

offset

The 'input DC offset errors' , you're writing about this?
I know that the input offset voltage being typically about 100 mV and the distortion is very low... even into a 600 Ohm.

Sorry, but i have understand your answer in correct way ?

www.bonisaudio.com

4

Re: Wrong Input Level Fireface 800

No, this is not about DC. And I don't know of any typical 100 mV DC anywhere.

Regards
Matthias Carstens
RME

Re: Wrong Input Level Fireface 800

Please, can you explain to me what kind of offset you're talking about ?

Thank you

Bonis

www.bonisaudio.com

6

Re: Wrong Input Level Fireface 800

Output level should be +13 dBu at 0 dBFS, but reaches only 12.8 dBu. Input should reach 0 dBFS at +13 dBu, but needs +13.2 dBu.

Regards
Matthias Carstens
RME

Re: Wrong Input Level Fireface 800

MC wrote:

Output level should be +13 dBu at 0 dBFS, but reaches only 12.8 dBu

This is the result of the levels without optimizing anything in re-recording, ok, thank you MC.

[img align=L]http://www.bonisaudio.com/Rme_ff800_check_level_and_loopback.jpg[/img]

www.bonisaudio.com

Re: Wrong Input Level Fireface 800

I am curious if anyone can confirm that the UFX behaves the same?

9

Re: Wrong Input Level Fireface 800

All our units. This is by design, means intentionally.

Regards
Matthias Carstens
RME

Re: Wrong Input Level Fireface 800

bonis wrote:

Output level should be +13 dBu at 0 dBFS, but reaches only 12.8 dBu

The RME units are music recording tools, not scientific measuring instruments!  They've been designed with a little extra protection against overload - when you THINK you're hitting 0dB you're actually a little lower.  Less chance of overload.  Don't worry about it.

11 (edited by bonis 2012-09-24 02:34:08)

Re: Wrong Input Level Fireface 800

Laurence, i have not complained, but i think the users who buys this card requires hight precision, otherwise i think to buy a Sounblaster, i have only asked this for know if some of my outboards was defective.

MC
I thought at first that you were talking about DC OFFSET, after i have understood what you meant.

PS
Here in my part (country) the DC OFFSET has a positive or negative domain range and this values are generally measured in mV.

www.bonisaudio.com

Re: Wrong Input Level Fireface 800

bonis wrote:

Laurence, i have not complained, but i think the users who buys this card requires hight precision, otherwise i think to buy a Sounblaster, i have only asked this for know if some of my outboards was defective.

I see your point.  But it's a musical tool, not a scientific measuring device.  There are different kinds of "precision".  If a slightly optimistic metering strategy decreases the chance of overload, and therefore huge loss of musical "precision", it can be considered a good idea!

I hope this imprecision-by-design is documented thogh?

13

Re: Wrong Input Level Fireface 800

You ever tried to listen to a 0.2 dB level difference? You ever checked your other equipments accuracy (be prepared for some surprises)? The 'precision' is there, even with levels. We are talking about things where other manufacturers would not give any information at all...

Regards
Matthias Carstens
RME

Re: Wrong Input Level Fireface 800

Sometimes I miss a "Like" button on this forum... cool

Regards
Daniel Fuchs
RME

15 (edited by bonis 2012-09-24 20:48:42)

Re: Wrong Input Level Fireface 800

I REPEAT DO NOT HAVE COMPLAINED ABOUT HIS ACCURACY,
we all know the analogic limits in terms of perfect precision, now that i know...compensating.... smile

MC
When you mix 12 tracks also use your eyes @ ears ?

www.bonisaudio.com

Re: Wrong Input Level Fireface 800

MC wrote:

Output level should be +13 dBu at 0 dBFS, but reaches only 12.8 dBu. Input should reach 0 dBFS at +13 dBu, but needs +13.2 dBu.

Please can you tell me the dBu or dBV value of this -8.7 dBfs ???

[img align=L]http://www.bonisaudio.com/8_7_dbfs.jpg[/img]

www.bonisaudio.com

17

Re: Wrong Input Level Fireface 800

+13 dBu - 8.7 dB = +4.3 dBu

Regards
Matthias Carstens
RME

Re: Wrong Input Level Fireface 800

MC wrote:

+13 dBu - 8.7 dB = +4.3 dBu

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www.bonisaudio.com

19 (edited by bonis 2012-10-09 22:20:37)

Re: Wrong Input Level Fireface 800

Sorry but i'm a little confused with your +13 dBu at 0 dBFS.....

0dBFS is the level that the converters will clip ??

In a digital audio system the nominal line level is +4dB and full scale is often +22dB (18
dB of headroom) ??

0dBFS in this case is +13dB.

Consumer audio is usually specified as -10dBV for line level which is roughly 12 dB less ??

www.bonisaudio.com

20

Re: Wrong Input Level Fireface 800

Chapter 25.1 in the manual.

Regards
Matthias Carstens
RME

Re: Wrong Input Level Fireface 800

Chapter 26.1 in the manual. (Analog Outputs)
In the Reference talk about Hi Gain, but under (in the description) talk about Lo Gain.
Thank you MC

Ps
Great work @ Musikmesse 2012

www.bonisaudio.com

22

Re: Wrong Input Level Fireface 800

You use an outdated one. The latest one can be downloaded from our website.

Regards
Matthias Carstens
RME

Re: Wrong Input Level Fireface 800

MC i have the latest one, thanks anyway. :-)

www.bonisaudio.com

24

Re: Wrong Input Level Fireface 800

No you haven't. But yes, you couldn't. Because it is not yet on our website :-)

The FF 800 manuals have been completely updated to the latest drivers, I will upload them in about 2 weeks.

Regards
Matthias Carstens
RME

25 (edited by bonis 2012-10-12 18:29:54)

Re: Wrong Input Level Fireface 800

R O T F L

www.bonisaudio.com

26 (edited by bonis 2012-11-25 01:43:42)

Re: Wrong Input Level Fireface 800

MC wrote:

We are talking about things where other manufacturers would not give any information at all...

One last question on this topic, yikes
attacking a very normal multimeter (value 22 €) with a sine (1kHz) @ -13 dBFS (0 dBu) what value i have to read from the display by connecting the leads between TIP and SLEEVE (about/approximate) if my FF800 work right ? (...without any load...)

[img align=L]http://www.xstreme.it/FF80MULTIM.jpg[/img]

Thanks

www.bonisaudio.com

27

Re: Wrong Input Level Fireface 800

Invalid usage. You have to connect ring to ground. Or measure between ring and tip.

Regards
Matthias Carstens
RME

28 (edited by bonis 2012-11-25 12:05:17)

Re: Wrong Input Level Fireface 800

MC wrote:

measure between ring and tip.

ok, thanks, in this case what value i have to read from the display of multimeter ? (with 1 kHz sine @ -13 dBfs) ...(ABOUT)... :-)


(i have updated the drawing)

www.bonisaudio.com