Topic: RME ADI-2 DAC clipping - solutions?

Hi,

I am using an RME ADI-2 DAC that feeds into a Moon 340i integrated amplifier. I am using the XLR balanced outputs on the RME. I have the reference setting at 13dbu as this is what I've read is best for balanced output. It also gives me a bigger, fuller sound I like. I have the volume at 0 on the RME. However, every so often I find some songs will clip and there is a slight level of distortion. It usually happens with high vocals. The bars on the RME turn into yellow at the high end of the scale.

To get rid of this, I lower the volume on the RME to -1 and it seems to solve the issue 90% of the time. For the other 10%, I lower the volume to 2.

My questions is, am I missing out on anything having the volume at -1 instead of 0 with the reference at 13dbu? To my ears, the sound recesses every so slightly but a silver living is that dynamics improve a tiny bit at the same time.

Am I best off trying to keep volume as close to 0 as possible with a fixed reference of 13 into an integrated amplifier? Or perhaps there's a better setting with a low reference level and a very low volume that I'm not aware of? Please remember, I am using the RME as a DAC only, not a preamp.

Thanks for your help and advice.

2 (edited by ramses 2020-08-08 19:55:34)

Re: RME ADI-2 DAC clipping - solutions?

According to the technical data on this web page
https://www.hifi-im-hinterhof.de/moon-n … l-techdata
The input sensitivity is: Eingangsempfindlichkeit     370 mV - 3,0 V RMS
3,0 V RMS are 11,5 dBu with a SNR of 110 dB
So if you deliver 3,0V RMS = 11,5 dBu with the ADI-2 DAC, then you achieve the maximum of 110 dB SNR at the premap section of your integrated amplifier.

Now look at the ADI-2 DAC, it has a higher SNR at these Reference Levels:
Rauschabstand (SNR) @ +7/+13/+19 dBu: 117 dB RMS unbewertet, 120 dBA
So we should simply concentrate on the Amp side not too go too low under the 3,0V but also to preserve a little headroom not to overload the input.

13dBu is too high, it results in 3,46V, therefore the distortion that you hear. And the level becomes even higher if you add Bass or Treble at the ADI-2 DAC.

If you would use Reference Level of +7dBu then you would have the full SNR of the DAC at Volume of 0.
On the Preamp side of your integrated amp you have still enough headroom for using Bass and EQ.

There are two possibilities for settings at the DAC

1) fix setting of reference level to +7dBu, then you have 4,5 dBu headroom for e.g. adding 3 dB Bass and 1dB Treble at the ADI simply to put an example for what you need to reserve such a headroom.

But should you make use of different Bass / Treble or even PEQ settings or dynamic loudness where its not easily clear, whether you add something to the signal or lower it, then I would tend to use the next option ...

2) Auto Ref Level settings. Let the DAC calculate the required reference level and watch the display at what volume level at the DAC the reference level automatically changes between +7 to +13 dBu. But set it to the value where the DAC just comes back to use a reference level of +7 dBu. Remember this volume level !!!
But +7 dBu are only 1,73V, you can make it still louder up to 11,5 dBu which is 2,91V.
12 would be too much, as this is 3,08 which is over the 3V which are possible.
So .. add 4,5 volume to the DAC and now you are at the sweetspot of your amp for maximum SNR.
Remember this volume setting as well, louder than that is not possible.


You need to take now simply an operational decision whats more fun for you. Static or Dynamic settings.

If you intend to use features like dynamic loudness or even PEQ B/T settings on the DAC the best would be to use the dynamic settings with auto reflevel.
After changing the settings you need simply to find the volume setting where the ADI-2 DAC is still at reflevel +7.
You see it in the display .. no magic .. simply look.
Then add lets say 4 or 4,5 dBu to the volume and this is your new maximum.
At the end an easy not too difficult task.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

3 (edited by kbrooke 2020-08-09 03:33:06)

Re: RME ADI-2 DAC clipping - solutions?

Thanks for that advice. Very helpful.

I've read that the +13dbu is best used for balanced, and also read that 13dbu with volume at 0 was optimum,  but are you saying my Moon amp would be better off with me using the auto reference and letting it switch between +7 and +13 dbu where appropriate? I basically want to set my RME DAC and not play around with the EQ features.

Re: RME ADI-2 DAC clipping - solutions?

It's not the ADI-2 DAC that's clipping, but you amp's input can't handle the +13dBu.
Go for +7dBu Reference level, 0dB volume.

This way there are some few dB headroom for the amp's input electronics.
Soundwise it's usually better not to drive electronics very close to clipping.

5 (edited by mark2748 2020-08-11 15:09:06)

Re: RME ADI-2 DAC clipping - solutions?

The explanations here are very helpful, except I am confused by one thing.
The OP uses balanced XLR output from the ADI-2 DAC.
Based on the RME User's Guide and other forum posts, I thought the output signal traveling down the XLR cables is always +6dB relative to the ADI-2 DAC Volume Line Out screen.  If so, would the DAC volume settings recommended above have to be decreased by 6dB?
Please clarify.  Thanks.

6 (edited by ramses 2020-08-09 17:19:30)

Re: RME ADI-2 DAC clipping - solutions?

The other way around, Reference Levels are at the XLR outputs: +19 dBu, +13 dBu, +7 dBu, +1 dBu @ 0 dBFS
With Cinch/RCA output levels are simply 6 dB lower (+13 / +7 / +1 / -5)

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

7 (edited by mark2748 2020-08-11 14:50:19)

Re: RME ADI-2 DAC clipping - solutions?

I think the ADI-2 DAC FS User's Guide could use just a few more words with regard to what the Volume Line Out display screen actually represents.

Re: RME ADI-2 DAC clipping - solutions?

The display shows you the actual reflevel +19 dBu, +13 dBu, +7 dBu, +1 dBu
Together with the information in the manual, that cinch/XLR is -6 dB lower it should be clear.

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

Re: RME ADI-2 DAC clipping - solutions?

Great, thanks. I find +7dbu with 0 volume to be a little lacking in body and scope. Sound is good but feels like it is underpowered & needs to breath a little more.

I feel the sweet spot would be between +7 and +13 it seems, perhaps around +11. My amps input is 3v.

Even though I’m using the RME as a dac only, not a preamp, would auto reference be advisable to use? Perhaps this would adjust where applicable?

I love the sound of this DAC but feel like I’m just a little either side of the sweet spot!

Re: RME ADI-2 DAC clipping - solutions?

Our ears work this way, that louder sounds better.
When A/B comparing two different settings you need to ensure, that
- the final  listening level is the same and
- A/B comparisons can be performed quick within seconds
And best performing it blind or double blind ...

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13

11 (edited by KaiS 2020-08-09 21:58:04)

Re: RME ADI-2 DAC clipping - solutions?

kbrooke wrote:

... I find +7dbu with 0 volume to be a little lacking in body and scope. Sound is good but feels like it is underpowered & needs to breath a little more.

I feel the sweet spot would be between +7 and +13 it seems, perhaps around +11. My amps input is 3v.

It's quite common, you probably like some amount of distortions.
Nothing else changes over a wide range of levels.
Non of the above changes as long as you're in an amp's linear range and compensate for exact same listening level.


You urgently need a source for a digital full scale sine wave test signal.
Any will do, file from internet, test cd, app.
Something between 400Hz to 1kHz works best, 0dBfs (digital fullscale)

Play the sinewave and listen at what level (using ref. level  and vol. control)  hard, clipping distortion starts.
Usually this point is very obvious.

Note the level down as clean reference.
Now, listen to music (modern masters are almost always full scale), check if you like it some amount above your clean reference.

12 (edited by mark2748 2020-08-11 15:14:42)

Re: RME ADI-2 DAC clipping - solutions?

The display shows you the actual reflevel +19 dBu, +13 dBu, +7 dBu, +1 dBu
Together with the information in the manual, that cinch/XLR is -6 dB lower it should be clear.

Apparently the above is not true for the ADI-2 DAC FS, per MC's comment in another thread:

Re: Asking kindly for your help to configure ADI-2 DAC solely as DAC

@ramsese: some confusion here. If you set +13 dBu (visible in the display) you get +19 dBu at the XLR output. The DAC does not have a +19 dBu setting in the display. The RCA is not 6 dB less than this setting, the XLR is 6 dB +.

Re: RME ADI-2 DAC clipping - solutions?

Sry, my confusion came from the manual section with the technical data, see here:

See this other thread: https://forum.rme-audio.de/viewtopic.ph … 14#p157814

BR Ramses - UFX III, 12Mic, XTC, ADI-2 Pro FS R BE, RayDAT, X10SRi-F, E5-1680v4, Win10Pro22H2, Cub13