Hey guys, I’m new here and can’t find quite the answer to a question I’ve had. If im using a dongle dac, such as the Moondrop Echo B, will turning the volume down decrease the quality of the signal? Will turning down volume on an android act the same way as turning down the volume in an OS like windows? Or does the dac bypass this problem? I’m using Quboz through USB Audio Pro, just FYI.
Thanks for any helpful information
If the dac has its own volume control then setting the device (phone, computer) volume to maximum and using the dac to control volume will be best.
If the dac has no volume control then your only choice is to use the device volume control.
Most people would put this in the category of splitting hairs so it’s not really anything to worry about.
Nope, common misconception. Some delta-sigma DACs have abnormally rising distortion as you get close to max digital volume at their inputs.
Both analog and digital components are best kept at least a few steps back from their max. volume if your focus is signal quality preservation.
Wrt. the original question, as this same article argues, as long as everything is competently designed (digital device noise floor always below the analog device noise floor), there’s nothing audible that you would lose by working only with the digital volume control to turn things quieter.
Keep in mind that the DAC/amp having “its own volume” doesn’t automatically mean it’s implemented in the analog section, it could still be working in the digital domain. You need detailed specs to know for sure. With something like a DSP-capable Moondrop Echo B, I wouldn’t be surprised to see its volume control (if it has an independent one) working on the digital side. But as discussed, there would be nothing wrong with that signal-quality-wise for most of its range below the last few steps at the top.
Digital volume is roughly the same everywhere, with some differences in how the quantization noise is kept under control through dithering and noise shaping. There have been many versions of Windows and there are many versions of Android, and implementations in both have evolved, but AFAIK any recent version of Windows should be fine, while with Android you should be careful that your audio doesn’t get resampled by the OS inbuilt resampler after it comes out of your player app and before it reaches the DAC. Since you have UAPP, make sure it’s always working in exclusive mode and talking directly to the DAC, and your digital volume control should work perfectly fine.
Hmm, this is the first time I’ve heard this. And while I truly appreciate you posting a reference to back up your claim, there are some gaps in the article’s explanation in my opinion. For example the animated chart is fairly convincing, but how do we know this isn’t the result of using a badly designed sigma delta DAC to prove a point? In theory, at least, a DAC should not be expecting the incoming digital signal to be attenuated in order to perform optimally. At least not a desktop DAC. I could see a dongle DAC needing to make compromises, one of which could be expecting the phone’s volume control to be used.
I’d really appreciate someone with far more knowledge of DACs, like @GoldenSound, to weigh in on this.
It also doesn’t seem worth the tradeoff since max-value samples will be rare.
You wind up with processing artifacts 100% of the time to prevent an occasional millisecond of max value distortion (if it exists at all).
So basically best case scenario is a dac with its own volume control? Even though it’s splitting hairs, there’s no way to avoid signal degradation if the source volume isn’t maxed out and allowing the dac to filter the volume?
The problem shown wasn’t only manifesting at absolute max, it was showing up across at least 10 dB of the top of the range, so about the last 2 doublings before max. With the amount of compression being applied in some music genres that’s a pretty populated region, it’s not like you’re going to count those samples on your fingers.
Processing artifacts? Turning down the digital volume in competently made software these days produces no audible artifacts. It only lowers the SNR, and if everything in the chain has been designed right, that is also not audible, it’s just the “natural” SNR reduction you “asked for” by turning the volume down.
Without going all lab-coat forensic analysis on your specific DAC you won’t know exactly which settings produce the absolute best results, but it’s a reasonable general rule to turn everything down from max once you know the pathological case above exists, and once you know your player software and/or OS are updated enough to apply dithering and noise shaping when changing your volume, such that even Red Book can be pushed to a perceived 20-bit equivalent SNR. Cutting 2 bits from that isn’t much of a sacrifice if it’s going to save you from 3rd harmonics pushed up to the -70s in dB vs. the signal, or the signal-modulated noise floor pushed up to the -90s (see the puffed up sidebands of the fundamental in the example).
Never used a dongle or UAPP. So take all of the following with a grain of salt. I think donjoe0’s remark above may address the OP’s original question though.
The Moondrop Echo B is technically a DAC/headphone amp. But it does not appear to have a volume control for its amp. So volume would usually be controlled by the digital device it is connected to. It looks like UAPP may be able to use the Moondrop DAC’s DSP to control the volume though, in exclusive mode.
If you want the volume buttons on your Android device to also use the DAC’s DSP to adjust volume, then you may also need to enable UAPP’s hardware volume setting. Or you could just use the volume slider in the UAPP app, I guess.
These supposedly allow you to bypass any potential downconversion of the audio signal in Android’s volume mixer.
I think there can also be some downsides to using these features though. Particularly if you’re using others players or apps to listen to music on your phone. So you’ll probably want to look at the pros/cons of using UAPP with these features, and whether the small improvement in audio quality is really worth the potential hassles and inconvenience of using UAPP’s exclusive mode.
+1. Super* Review would probably also have some good thoughts on this.
I usually max out all the software volume settings on my PC btw. And will even let them excurse slightly above 0 dBFS at some frequencies (which I don’t generally recommend) when using EQ. And try to use only my analog amp downstream for volume attenuation before the signal reaches my headphones.
I think this delivers the best signal quality, voltage, SNR, and dynamic range in my particular setup. YMMV though. I only use over-the-ear type headphones in my setup btw. So no higher sensitivity IEMs.
Have you actually tested this on multiple DACs? This behavior seems like a faulty implementation.
Unless I’m missing something Amir at ASR tests DACs at 0dbfs or very close to that.
Eg the Motu M4:
No, I don’t have the equipment to test this out for myself.
I will grant that since the article was published in 2016 that conclusion might be outdated even for dongles like OP is using, and that newer DACs might hardly ever have this problem anymore. But on that note, I will stand even more firmly for the conclusion that there is nothing wrong with - and might in fact be optimal - using primarily digital volume control these days, and keeping the analog side at a fixed sweet-spot volume setting (usually quite a bit lower than max, as shown also in Amir and Professor Wolf’s results, where the THD+N vs. output level graph most often curves up and even hits clipping for the last several doublings of volume).
For my part, I will still always keep the digital volume at least one notch lower than max, simply because of engineering experience proving that 99.99% of the time real-world physical implementations do not follow the nice simple formulas that produce perfect results on paper. There are always trade-offs in the real world, and there’s usually something to lose operating any device right at the end of its advertised range. (It’s all too easy for non-engineers to get illusions of perfection with digital technology because “it’s all ones and zeroes” and should produce perfectly predictable results at all times; little do they know it’s all still fundamentally analog and error-prone, if they’ve never gone in-depth and looked at digital transmissions on an oscilloscope.)
