yashsingh1/xdaforums huggingface dataset:
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
Stepped Sine Test of the Earstudio:

Not much better than a decent Dac Dongle. I did not look at impedance but it's below 1 according to the specs, and did not look at crosstalk.

Notice that the distortion seen with a simple sweep (what many folks measure) is not too bad:

Perhaps the stepped sine test provides a more dynamic signal change, making it more challenging.

I did look at AptX HD vs LDAC (best quality):

Here is LDAC playing a 1khz sine:

AptX HD

THD and noise about the same.

Sweeps for each (normalized to a scale of 100%):

LDAC:

AptX HD:

They both have about a 1% THD/noise floor that bumps up above 10 khz. Younger ears in a quiet room probably could discern this. Outside or in the GYM, probably not.

Bottom line:

Not bad, but not in the league of my Chord Mojo.

Slightly better than a dongle.

AptX HD sound quality (by these narrow tests) about the same as LDAC high quality setting.
[Google Pixel 2 XL Guides, News, & Discussion] mrkmrk:
i'm guessing that that was measured unbalanced, right?
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
Yes
[Google Pixel 2 XL Guides, News, & Discussion] mrkmrk:
gotcha; can't imagine it makes a particularly measurable difference anyway. would you mind explaining about how it's slightly better than the dongles? you can assume i know about FFTs and how logarithmic scaling works, but i'm very unfamiliar with a lot of the specific tests. and did you measure some of the other things you measured for the dongles, like crosstalk?
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
The slightly better refers to the capacity to also do Apt X HD, LDAC for a remote solution (if you want to be wireless).

I didn't do crosstalk.
[Google Pixel 2 XL Guides, News, & Discussion] elzafir:
I just got a new Xiaomi Mi A2 and the included Type C to 3.5mm adapter is absolute trash. This thread is a god send. The internet is seriously lacking of USB Type C to 3.5mm cable DAC comparisons. Although, the information on here goes way above my head. I have no idea which is better. From what I can gather, the Dragonfly is best, the Apple is good and better compared to Google's V1. How does the Apple compare to Google's V2?

I usually listen with a $30 Xiaomi Mi In-Ear Heaphones Pro HD (32 ohm impedance; my main tool IEM) and a $45 Superlux HD661 headphones (68 ohm). I'm planning to get Audio-Technica M50x (38 ohm) in a short while to replace the HD661 as my main on-the-road headphones.

I have an option to buy the Apple one for $10, Google's V1 for $14, and the HIDIZS Sonata II for $41. Which one do you think I should get? I don't want to spend to much on the Sonata because my headphones are cheap and it wouldn't make sense, unless I absolutely have to.
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
None of the units are "bad" but a few comments.

Both the apple and dragonfly, don't put out full voltage on stock Android. If you already have them it's still worth trying, but I wouldn't invest in the dragonfly otherwise.

The newer Google DAC has a high impedance which could mess with the frequency response of some low impedance multi driver iem's.

I personally like the apple Dac based on size, cost and quality.
[Google Pixel 2 XL Guides, News, & Discussion] Large Hadron:
Actually after updating my Dragonfly Red to the latest firmware it outputs the full volume using stock Android and PowerAmp, whereas prior to that I had to use USB Audio Player Pro to get decent volume. I suppose I should test with Spotify or something to check this works across the board, but don't have it with me at this moment.

(This is with an up-to-date Pixel 2, just in case there's any residual Android version dependence).
[Google Pixel 2 XL Guides, News, & Discussion] Geo2160:
The XZ3 dongle is passive. The DAC is integrated in the phone.
[Google Pixel 2 XL Guides, News, & Discussion] derbidrd:
Hi ! Is there any way to get 1V output with windows 10 ? Thank you.
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
Last I checked, it seems fine with Win 10 now, full 1 V. Just make sure the headphone cable does not have a mic. The Dongle does weird things if that's present.
[Google Pixel 2 XL Guides, News, & Discussion] derbidrd:
Thank you, finally after debating in audiosciencereview it looks like european model can't output more than 0.5v (Model A2155)
[Google Pixel 2 XL Guides, News, & Discussion] frustr8ted:
I got a Pixel 3 - compared to my Sony XZ1 (Compact) it lacks a insane amount of bass.

To be a bit more specific - there is no punch/oomph to it. Using KZ ATE and Westone UM3 Pro. This combination served me very well on my Sony and as of now I'm a bit shocked by how lifeless the "flagship" Pixel 3 performed audiowise.

Is the USB-C to 3.5mm dongle to reason to all this?
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
Yes, the entire audio capability of the Pixel is in the dongle. Try a different dongle, the stock Google unit is the worst.
[Google Pixel 2 XL Guides, News, & Discussion] L.F.B.:
This thread is really amazing!

Guys i know that dragonfly red rocks! But, how about the other dragonfly? Are they any good?

For me the DF red is a little expensive and the others DF adapters are more a"affordable"...

I know the apple dongle is good but its only 24/48... I want at leat 24/192 dac...

Another question is. I want to buy the OnePlus 6t. How about the dongle? Is passive? Is it good?

Thanks in advance!
[Google Pixel 2 XL Guides, News, & Discussion] Powereh:
If you don't root then the apple dongle is completely rubbish, Far too quiet!

Thought i'd give it a try after using Googles, HTC's & Razors & all of them breaking after a few months... Can't say I am too impressed with their dongle.
[Google Pixel 2 XL Guides, News, & Discussion] akgrown:
Friendly request to measure the new Samsung DAC they released to support the Note 10/10+:

Samsung USB-C Headphone Jack Adapter
[Google Pixel 2 XL Guides, News, & Discussion] Aukash:
Can you please forward me what to do after Root. I'm a noob so step-by-step instructions would be nice ?
[Google Pixel 2 XL Guides, News, & Discussion] Utini:
Then what DAC unit should I use for my P4 XL? The apple one is simply too quiet and it seems like I also can't fix that with viper4android.

I am listening with VE Monk+.
[Google Pixel 2 XL Guides, News, & Discussion] rootuser11:
i appreciate all the information you provided here, thanks. I also do hope google reads this and actually do something about digital gain - defaulting to max is a bit too much.
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
With all the focus on the screen woes, audio backend may be low on the priority list.

I also wonder if they, in their own way, are responding to previous criticism when the USB Dac would not reach it's maximum voltage output in older Android versions. Unfortunately, they took it too far.
[Google Pixel 2 XL Guides, News, & Discussion] rootuser11:
That might be true but they are also working on some audio issues with Pixel 2 (which I do hope that they fix because otherwise i am returning this phone) and they went too far. I am considering using the dongle for nexus 5x for the time being that has root and nexus 5x has notorious headphone jack that causes a lot of interference with some of my headsets. do you have any guide on which file should be edited to achieve what you did in your post about removing distortions? digital gain was reduced there. Thanks.
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
Absolutely, this is my old app that addressed that, as well as Biquads support. I still use that on my old Note 4. Or you could also skip the app and just edit your mixer paths file to reduce the gain in the analog output (HPHR, HPHL).
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
A few more observations and test results:

After having the phone for the past week and getting more familiar with it's quirks, I would like to report what I have found.

This is a 1 kHz sine played with Gmusic, native driver and supplied dongle

Not too bad, save for the mild distortion spikes.

Interestingly the spikes really don't change as the volume is reduced:

Obviously something is not right.

For comparison this is my old Note 4 playing at stock settings(I can make this much nicer with analog gain tinkering):

Things get more interesting if you decide to engage the Equalizer:

So you don't want to do that.

It's also not strictly from clipping, this is a 10 dB cut at 1 kHz:

Still not nice.

How about using the Neutron player driver (it will only work in the app).

Clean with no distortion bands!

Even at a very high output there is very minimal distortion (would not be audible):

This is at a level that is near my usual listening volume with SE846, output about 86dB.:

Again, very clean.

Comparison the the Dragonfly Red:

The native android driver is fine with the Dragonfly

But it's probably because the Dragonfly digital gain is set very low, the following is the maximum voltage obtained with stock driver:

So the comparison is not totally fair.

To save some time I will say that the Dongle and Dragonfly have similar impedance (very low) and crosstalk.

The Dragonfly came in at -62 dB and the Dongle at -53 dB. For comparison, my old Note 4 was a meager -35 dB.

The bottom line is that even using stock drivers the Dongle is not too shabby but with the proper software settings it can be quite impressive.

The distortion bands are similar in magnitude regardless of (usual listening) volume - so when you see a RMAA test at full scale, the THD will not appear too high. But at lower levels the S/N ratio gets much higher. You will not see that mentioned. The low output impedance will keep a flat freq response with low impedance multidriver IEM's (like my Shure se846). The excellent crosstalk will also result in great channel separation.

With respect to Neutron player driver, it probably limits the DAC digital gain, and avoids the distortion banding. But, you will lose notification sounds and phone call audio with the USB adapter attached (speakerphone works).

Users with Gmusic streaming, Spotify, Tidal are stuck with the stock android driver/settings. Using the on board equalizer will further degrade the signal (even if you only cut a band, and frequency of the bands are not adjustable).

If high signal quality is important, you may want to use a Dragonfly for now. Also note, the output to the Dragonfly is still 48 KHz (but that is fine).

After root is achieved, it should be simple to adjust down the DAC digital gain of the Dongle, or raise the digital gain of the Dragonfly.
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
Review of Geekria USB Dongle

Just in case you lose your Google supplied USB Dongle...

Price is about the same ballpark (16$).

What is inside the unit?

So a Conexant chip..

Some different sample rate choices:

Audio testing...

First off, maximum voltage out in android- about 330 mV:

Distortion banding not too bad, without any loading.

Crosstalk, no load:

With load, not as good (but reasonable):

Frequency response with a difficult load (SE846):

The output impedance is about 5 Ohms, so the same as the orig Pixel (mediocre).

Distortion bands with load (SE846), using Neutron driver:

First the Geekria....

The Google supplied Dongle(same voltage):

The Google Dongle is not immune to the banding, just happens at higher output:

Summary:

The Geekria is a Conexant USB Dac

Sample rates 44.1/48K which are both options in Neutron (not plain android)

Max voltage is only .33 volts (fine for IEM's)

Output Impedance is 5 Ohms, there may be frequency response shifts in multidriver headphones.

Crosstalk does degrade with load but still very good.

Distortion somewhat higher than the Google dongle in some circumstances. Whether this is audible or not is a question.
[Google Pixel 2 XL Guides, News, & Discussion] stormet:
Thanks for the measurements!

I am actually thinking to get a dragonfly red.

Can you please share if the dragonfly red will be working properly via a otg cable to Pixel XL 2?

Does it work with stock google music player? YouTube, Spotify, etc.?

Or must I use the Neutron player or other 3rd party pro players to make it work?

Kindly advise. Thanks.
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
The Dragonfly is a superb device.

It checks all the boxes, ultra low impedance, low crosstalk with difficult IEMs, low distortion and of course 2.1 V power out.

The problem is my Pixel will not get more than 55 mV out. This is the reverse situation from the dongle, so the OS is using a very low digital gain from the Dragonfly(excellent to minimize distortion). My old app was able to fully adjust this and I was able to get 2.1 V. If you have sensitive IEMs, 55 mV is plenty, but if you want it for full power, we need to wait for my mods. My usual listening level is about 10 mV.
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
GSMarena came out with their review. The observation about volume out is interesting:

The Google Pixel 2 XL is easily among the loudest devices we have tested - in fact we had to record it at a step below its maximum volume as it exceeded the range of our equipment..

The specs in regards to crosstalk are in line with what I measured, excellent. Note, they measure distortion at near max output, so it will seem trivial. Unfortunately, they never look at distortion at real world listening levels and in this case, they would have seen what was presented above.
[Google Pixel 2 XL Guides, News, & Discussion] cstark27:
I know this thread is mainly about performance, but I thought this was kind of cool and wanted to share. When I plug the Google dongle into my PC, I'm able to use my headphones buttons to pause and adjust volume. Those buttons don't work if I used the 3.5mm port on the motherboard.

Anyway, thanks for the posts and info!
[Google Pixel 2 XL Guides, News, & Discussion] AphexSA:
Pixel 2XL owner here. Thanks for the detailed analysis. I have the Shure Se846 earbuds, and I got the DragonFly Red because of this thread, after noticing how awful music sounded on the 2XL's provided USB-C adapter compared to my old Pixel XL's headphone jack.

I got the Dragonfly Red today and was disappointed - even at max volume, it's not enough to drive my Se846 earbuds satisfactorily, and STILL doesn't sound as good as my old Pixel XL. Based on what I understand from your posts, is it correct to say that this is because the 2XL causes the Dragonfly to have very low digital gain? Or is it because the Dragonfly itself has low digital gain? Where is digital gain determined, the DAC or the phone? (I ask because as you mentioned, the stock Google USB-C DAC has the opposite problem, maxed-out digital gain.)
[Google Pixel 2 XL Guides, News, & Discussion] Freak07:
Did you use usb audio player pro?

If you just plug it in and play via stock driver exactly this will happen.
[Google Pixel 2 XL Guides, News, & Discussion] AphexSA:
All of my music is on Spotify so sadly that isn't an option. I'm guessing there's no way to adjust the gain for Spotify without rooting, right?
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
The Dragonfly will put out 55 mV max (instead of the 2.1 V it potentially could) with the digital gain Google uses now on the Pixel 2XL. If the SE846 was driven with 2.1 V, the Spl (1 kHz) would be about 140 dB. So if you drop to .055V, the loss is about 31 dB. This is still above 100 dB. I am not sure why you aren't getting plenty of sound. Have you tried some different players?

I am hoping someone from Google reads this and makes the appropriate changes. What would be nice is an option to adjust the digital DAC gain for users with different needs. However, the lower the digital gain, the lower the distortions will be (including the dragonfly). If you are listening with an android volume of 3-4 ticks, you are probably running at a very high DAC digital gain.

Root is needed to make the adjustments (my app is done, except for the needed root commands). I have an HTC dongle on order and one of these as well. It is possible that one of the aftermarket dongles will default to a reasonable gain setting without root.
[Google Pixel 2 XL Guides, News, & Discussion] Freak07:
Take a look at this post of me on the u11 forums.

There is a trick with usb audio player pro (uapp)

https://xdaforums.com/showpost.php?p=72798341&postcount=52
[Google Pixel 2 XL Guides, News, & Discussion] chdloc:
I highly doubt Google would act on suggestions and/or bug reports on XDA. I'd suggest you go the "official" route and file a request on the Android Issue Tracker here and have folks star the issue.
[Google Pixel 2 XL Guides, News, & Discussion] AphexSA:
Nice. Yeah, hopefully the DAC gain will be adjustable in the future, because from what you're saying, we're stuck with defaults for now, so we just have to try different dongles/DACs until we find one with a reasonable default gain setting (not too high, not too low.)

Can you post in here when you get the HTC dongle and the Capri dongle? Would love to see how those perform.

Meanwhile, I'll probably be returning the Dragonfly, because I can't get it to push out enough sound, even with Android media audio set at 100%.
[Google Pixel 2 XL Guides, News, & Discussion] jasenko:
Hi guys... Glad I found this thread, and if I found it earlier, maybe I could have saved some money. Was very disappointed with the sound quality of the dongle. Sure, it was able to drive my Shure SE425s but the distortion was making it unbearable to listen. Apple dongle by comparison produces some very sweet sound. Eventually, I ended up buying Dragonfly Black and could not be happier (although bulky). I thought, I could use it anywhere, so it wasn't a hard buy. The sound is amazing through USB Audio Player Pro (and as the renderer in BubbleUPnP), and very good overall when I don't use UAPP. Do you guys think that Google could make some improvements in the driver so the dongle sounds nicer? I would prefer if I don't have to have DFB hanging out of my pocket :)
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
If you have root, my app should be ready soon which will both boost the gain in the Dragonfly and limit the gain in the Google dongle (as well as be adjustable on the fly, so you can set it up the way you like). It will work on all players. There is really nothing wrong with the android driver, it just does not intelligently set the digital gain.
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
Very good news.

The Google Dongle performs quite well with proper gain adjustments.

I have a preliminary app that will adjust the DAC digital gain and android volume, tracings below.

Of note, for some reason using direct Tinymix calls up to the max setting of the Dongle (175) with an android vol of 25 (max), the maximum voltage drops to .9V (was 1.88). This was a complete surprise and I need to study this more and consult with my audio guru [MENTION=2760454]chdloc[/MENTION].

Anyway here is a comparison of lower vs higher digital DAC settings-remember 175 is supposed to be max.

Note the same voltage output but much less distortion with the lower DAC gain/higher android volume.

We start to get banding at 100 mV:

But most certainly not audible.

Next a look at crosstalk with increasing voltage. Recently gsmarena measured the Pixel 2 (not the XL) and it was much worse in the crosstalk department. Could this be due to effects of the voltage during the test?

It does change, but if anything may drop with higher voltage.

And finally a look at a triple sine wave, 25 hz, 19 and 20 Khz:

Very clean!

Bottom line- this is a super 9 dollar DAC if driven properly.
[Google Pixel 2 XL Guides, News, & Discussion] zachman1750:
Very good news! I'm patiently awaiting the app you're building, thanks for your efforts so far getting this all figured out.
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
Control app is out.
[Google Pixel 2 XL Guides, News, & Discussion] lycan_codex:
Sorry for the dumb question, if i set the digital gain to low (around 55-60 from 1-175), would i get clear audio from the provided dongle ? I am trying to buy a 70-85$ USB DAC and wondering if we can get similar quality if we root the device and set the digital gain to low through your app.
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
Absolutely

I have a Dragonfly red and they test out nearly the same if the gains are optimized. The torque on the usb port worries me if I am walking (or biking) with a Dragonfly attached, so I use the Google dongle mostly.
[Google Pixel 2 XL Guides, News, & Discussion] lycan_codex:
Awesome. Thanks man! I am looking for something like this. which has a clip where we can attach it while going out.

https://www.amazon.com/VELOUR-Portable-Earphone-Amplifier-Headphone/dp/B075N31ZP2
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
There appears to be 3 (at least) "modes" that the Google dongle will do. Depending on the impedance of the headset/line out device attached, the output voltage varies quite a bit.

Low impedance - .36 Volt (high efficiency iem's)

High impedance - .9 Volt (full size headphones)

Very high impedance- 1.8 Volt (line out)

What gets interesting is the effects on testing. The "reference" sites like GSMarena, are testing with a Y cable setup (as I was) and will see high voltage out even with headphones attached since the use case was taken from the line out initially. What made me aware of this was that my app was not reading the Spl correctly, as if the max voltage was about 7 dB down (which it was). Also of note, the reduction in output is not due to a change in the Dac digital gain (the one that adjust from 1 to 175), so the distortion bands are just as bad since they kept that gain at 175.

Added to Post #1
[Google Pixel 2 XL Guides, News, & Discussion] giodelgado:
I got my Pixel 2 mini two days ago, I'm suffering the same issue everyone faces since Android was created "equalizer" doesn't work properly using Spotify. Sadly, this is the model with "OEM unlocking" greyed out so have to wait for that fix too...

Any other options other than turning off equalizer?
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
Another Usb Dac may work fine (Dragonfly-but will not be at full power). I should be getting in the HTC dongle next week and will do some side by side testing, stock and optimized.

I will say that the supplied adapter provides super audio quality as long as the gain is turned down.
[Google Pixel 2 XL Guides, News, & Discussion] giodelgado:
I honestly think this won't get fixed by Google, they replied saying I should use "recommended" USB-C accessories only, which doesn't make any sense. The delay caused by their non-working amplifier has nothing to do with USB accessories.

I went back and tried to replicate this issue with 4-year-old devices like my Lumia 1020 on Windows Phone 8, no issue at all, might be because all devices had an internal DAC and Nokia always had an engineering team dedicated to audio enhancements, it even has Dolby Digital support when a headset is connected!

Anyways, I gave up on my quest to fix this issue, the phone doesn't have a DAC, the dongle is the only thing that improves the sound but no equalizer works on this phone.

Researched Qualcomm APTX technology, I already have a MMCX wired headset from Tennmak (Shure knock offs), really great sound! By accident found this wireless cable that supports MMCX detachable earbuds like Shure and Tennmak, features BT 4.1/APTX/sweatproof it even has equalizer presets, but I can't find any specific specs about the audio quality.

What do you think? http://www.itechdynamic.com/list_of_products/prostereol5/
[Google Pixel 2 XL Guides, News, & Discussion] bjrmd:
If you need a wireless solution aptx and the like are better than sbc. But you are still transcoding a lossy format(twice) to degrade it further. I think the final output will not be as good as even the stock dongle.

Also you don't know what the impedance of the amp is on the device, crosstalk etc which we know is great on the google dongle.

Why don't you hang on until I test the Capri solution and HTC dongle (hopefully this week)