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ADI-2 DAC Setup

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#1
Hi there! I am looking for some assistance setting up my ADI-2 DAC. I am coming from a plug and play Schiit Stack so as you can imagine there is a much bigger learning curve there.

On my own, I have enabled auto screen dimming feature and remapped some keys on the remote so I do not accidentally press them in the dark.

I am wondering if there are any must set setting when you start using this that I do not know about that might impact the quality of the music and games I play?
 

andreasmaaan

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#2
Not really, it should play fine out of the box ;)

But you should take steps to optimise it anyway.

What's your complete setup? I have the same DAC and can guide you through at least some aspects of setup if I know how you're using it.
 
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#3
I am using it on a computer and I have two Neumann KH 120 speakers.

Is that what you're asking for?
 

andreasmaaan

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#4
Yep, that's it. And in that case it should be very simple.

I would start with the KH120. Turn the "input gain control" knob to full (0 dB). Then set the output level control to 114dB (maximum setting).

What you've now done is stopped the KH120 from attenuating the volume. You'll be controlling the volume 100% with the DAC.

By default, the Adi-2 DAC sets the reference volume level automatically based on how loud you listen. This means you shouldn't have to do anything else once the KH120 levels have been set as I suggested.

However, if you find that the Adi-2 auto reference level is causing problems (e.g. by suddenly changing volume unexpectedly when you turn the knob too far), post here and I/we can help you manually set the Adi-2 reference level.

That's all you should need to do to get maximum performance out of the unit.

However, it does have a lot of interesting and useful features that you might want to try out. The most useful IMO are the graphic equaliser and the level-dependent loudness function.

The EQ I probably wouldn't play with unless I had a measurement microphone and could measure my speakers in the room. However you might want to try it and see if it subjectively improves the sound for you.

The level-dependent loudness function works by increasing the bass and/or treble relative to the midrange when you listen at low volume levels. This is because our ears become less sensitive to bass (and to a lesser extent treble) when the volume is lower (google "equal loudness contours" if you weren't aware of this).

If you're interested in playing with it, let us know and we can explain how to set it up.
 
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#5
Wow! That's exactly what I was looking for! Thank you very much!

I want to be in total control of my noise levels. Assuming that the Auto Reference feature doesn't do anything to enhance the sound quality, let's turn that completely off. I toyed around this this slightly when I first got it but I eventually just reset all settings because I was never able to get it set to totally 0. Is that even possible? It's always + or -.
 

andreasmaaan

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#6
Wow! That's exactly what I was looking for! Thank you very much!

I want to be in total control of my noise levels. Assuming that the Auto Reference feature doesn't do anything to enhance the sound quality, let's turn that completely off. I toyed around this this slightly when I first got it but I eventually just reset all settings because I was never able to get it set to totally 0. Is that even possible? It's always + or -.
No problem.

Re: auto ref, t's always + or -, yeh. But that's not a bad thing, since it's using a dBu measure. It's really just a case of optimising the gain structure for your upstream gear (the KH120 in your case).

I personally like to use the level-dependent loudness function, so I set my ref level manually. But if you're not using that function and the DAC is working well for you with auto ref, there's no need to change it.

The only other thing I'd suggest at this stage if you haven't done it already is to take the opportunity to make sure all the controls on the back of the KH120 are set correctly. You may already have all that set up though, in which case you can ignore this advice :)
 
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#7
So it's impossible to completely turn off the + or - then so that I am in 100% control? Or are you saying that I shouldn't worry about it?
 

andreasmaaan

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#8
So it's impossible to completely turn off the + or - then so that I am in 100% control? Or are you saying that I shouldn't worry about it?
No you'll still be 100% in control whether you have auto ref level on or off. All the ref level sets is the maximum output from the analogue stage of the DAC. Once it's set to the correct level (or when it's on auto mode), you still have complete control over the volume with the volume knob.

In fact you have more control if you set the ref level manually because then it won't adjust depending on how loud or quiet you're listening (although it won't normally do this in auto mode anyway).
 
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#9
I guess I am missing something. To me, I think I would want it to be +/-0. That way there is no + or - depending on my volume I am using with the knob.
 

andreasmaaan

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#10
I guess I am missing something. To me, I think I would want it to be +/-0. That way there is no + or - depending on my volume I am using with the knob.
Basically, the volume knob on the unit controls the volume in the digital domain, while the ref level sets the fixed (maximum) output level from the analogue output stage of the DAC.

The reason the feature exists is that every upstream device (amplifier or powered speaker) has an idiosyncratic input sensitivity (basically as a result of lack of standardisation). Most DAC manufacturers don't bother trying to deal with that, they just have a fixed ref level that can't be altered by the user. RME is giving you the option of changing the ref level so that you can be sure that you have the optimal gain structure in your setup as a whole. By optimum gain structure, I mean such that each link in the chain contributes the minimum possible noise and distortion.

Having said that, the level of noise present in the Adi-2 is so low in any case that it would be strange if there were any audible differences between the various settings. But it does allow you to choose.

But as I said, there will likely be no audible difference regardless which setting you have it on.

Also FWIW, the volume knob controls the DAC digitally, so the levels are in dBfs (i.e. referenced to a maximum digital volume level of 0), while the ref level fixes the maximum analogue output level, so it's in dBu (the standard for professional audio, where zero dB doesn't mean anything special in particular). I realise it's possibly quite confusing :)
 

AnalogSteph

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#11
After a bit of RTFM for the ADI-2 DAC (section 19.3 in particular), I see no reason to disable Auto Ref. It's basically just juggling digital level control and analog output stage gain for optimum SNR depending on volume level setting chosen. You have a crudely-stepped analog volume (/ gain) control, and then digital attenuation fills in the gaps. I would do the same.

The KH120 is making things a little more difficult than necessary for the amateur without a defined SPL reference level. First of all, the block diagram does not seem to accurately reflect the actual circuitry, as nominal input impedance changes depending on output level setting. (WTF? Plus, I would understand it if the input were at 10 kOhm and padded down via an additional 10k in series to achieve a 6 dB attenuation, but the table says 20 kOhm at 114 dB SPL and 10 kOhm at 108 dB SPL, exactly opposite from what I would expect.) So that setting must be doing more than controlling gain after the actual input stage. Documentation FAIL.

Anyway, the highest output level setting gives 114 dB SPL for a 0 dBu input if the input gain trim pot is all the way up. This is, in all likelihood, way excessive gain, considering that the input can accept up to +24 dBu and the ADI-2 DAC can output +19 dBu, and the speakers will only do 111 dB @ 1 m maximum with a bit of a following wind. (Not to mention you may not even want levels even close in a literal nearfield application. I would be more than happy with about 100 dB SPL.) Chances are that this setting will make some input stage noise audible at close range - I would expect an input noise level of somewhere around -100 dBu. But if you ever wanted to max out the speakers using a little Clip+ or 3.3V-only onboard sound (whose max levels are ~800 mV rms and thus in the 0 dBu = 775 mV vicinity), this would be the setting to use.

Here, I would probably try output level = 94 dB and input gain trim = 0 dB. That'll give 100 dB SPL @ 1 m each @ +6 dBu in. That's easily a low enough level for neither the input stage nor the ADI-2 DAC to break much of a sweat even at this rather high volume, and it should keep noise levels inaudible. +19 dBu would translate to 113 dB SPL, so if you really wanted to blast your ears, you could still do that. If you're running rather low digital levels like I do (ReplayGain + some EQ), 100 dB may be worth a shot instead. One of these two in any case.

EDIT: Not sure why the short delay digital filter appears to be the default for the ADI-2 DAC. As delay in the milliseconds is of no concern to us, I would think the regular Sharp filter would be the better choice. There was a firmware update concerning filters recently as well (check whether that's installed), I suspect there may have been some sort of screwup in selecting the right one. I hope they're making use of the traditional, low period ripple sharp filter that is also included in the AKM DAC chip now.
 
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#13
I love my rme. It has a bit of a learning curve. Give it a week or two and you'll have the thing down.
 
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#14
This is some usefully information about reference level that isn't clear unless you read the manual.

Line Output: Ref Level Sets the reference level for the analog outputs. Choices are -5 dBu, +1 dBu, +7 dBu, +13 dBu at the RCA output, referenced to digital full scale level (0 dBFS).

"The levels at the XLR output are 6 dB higher, +1 dBu, +7 dBu, +13 dBu, +19 dBu."

When I first got the unit I struggled to put it into +19 because it registers as +13 on lcd. You have to just add the 6db in your head if you're using xlr.
 

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