Preamble: The information below is a collective effort from several headfi members. I'd like to acknowledge contributions from @kundica, @chillaxing, @mlknez, @ra990, @Left Channel, @scottm18, @oddluck, @james444, @dragion and others I've obviously forgotten. I'd also like to acknowledge the developers of Neutron and UAPP for many useful communications. If you see a typo, an egregious error worthy of a class-action lawsuit, something you mildly disagree with, or if I've forgotten something important, please pm me and I'll update this post. Important disclaimer: I am not affiliated with any Android app dev team. If you prefer the sound of some other third party music app not mentioned here - even though it re-samples everything to 48/16 PCM - you're free to use it. The following information is intended only to help new V30 users. -- The LG V30 is an awesome phone for music. Actually it's an awesome phone, but that's a review for another day; this post is strictly about the V30's audio. The V30 has a 3.5 mm headphone socket with quad ESS 9218P DAC and an amplifier that automatically adjusts output power to match your headphones. The V30 has an output impedance of approximately 1 Ohm, which is very good (using the typical rule of 8, it should do no harm to the frequency response of any headphone ~8+ Ohm impedance). Most people will be able to simply plug in their favorite headphones and enjoy surprisingly high-quality sound without needing to carry around a separate DAC/amp. Most of you won't need to worry about this thread. You can simply stop reading here and go and enjoy your V30, and/or hang out on the main V30 thread: https://www.head-fi.org/threads/lg-v30.858933/ Still reading? Cool. There may be some extra goodness you can squeeze from the sound quality of your V30. There are several little rabbit holes to go down here. Make your choice below, or simply take a shortcut to the recommended music apps at the bottom: Spoiler: Tricking the V30 Amp into Giving More Output Power The V30 has three gain modes: Regular device mode, Aux (external device) mode and High-impedance device mode. Currently, there's no known way of manually setting the gain mode on the V30 - it's set automatically by the V30 as a function of the attached device impedance. On your headphone's TRS connections, the V30 checks the resistance across T & S each time you plug in your headphones (T & S is the left channel - T & R aren't checked). If it detects < 50 Ohm, it switches to "Normal device mode"; between 50 Ohm and ~ 750 Ohm, it switches to "High impedance mode"; above ~ 750 Ohm, it switches to "External device mode". For most people, this is totally sufficient. But there are headphones (e.g., planar magnetic headphones) that are simultaneously low impedance and low sensitivity. Some may prefer more power to drive such headphones to louder volumes or create more headroom. There have been several suggestions on the main V30 thread for this. The idea is to first plug in an adapter which will trigger aux or high-impedance mode, and then plug in your headphones to the adapter. There are variants to this trick: for example, if your headphones have removable cables, removing them first, and re-attaching only after you've plugged in the 3.5mm plug to the V30, you will trigger aux mode. I generally don't recommend permanently leaving an impedance adapter in series just to trigger high-impedance mode; this isn't only taking one step forward to take one step backward, but it's also changing your headphone's frequency response. Here is a passive adapter I've tested (so I know it works in triggering aux mode, which has been sufficient for me): https://www.amazon.com/gp/product/B00GZQWI6C If you need even more power than that from aux mode, check out the following tip posted by @ra990: https://imgur.com/a/53lKd Note that not all V30 firmwares tell you which mode is currently active. If your V30 doesn't report this, @dragion found this app on the Playstore that you can use: https://play.google.com/store/apps/details?id=com.apptrio.hi_fi_status&hl=en P.S. The output impedance can be measured using the third method in the video below (you need method 3, because checking the voltage drop across an infinite impedance load will trigger the V30 to switch to "external device mode"): From two resistance loads, R1 and R2, you can then determine the output impedance from: R0 = (R1-R1*V1/V2)/(V1/V2-R1/R2) In all three modes, the V30 output impedance measures ~ 1.3 Ohm. The key point here is that the output impedance does not change with the amp's output mode - it does no harm to the quality of the audio output to trigger "external device" or "high-impedance device" mode. Spoiler: The Sampling Rate Issue In an ideal world, your music player would play back all your native file formats directly, without going through any further digital processing or conversion. You most likely need to do a bit of extra work to achieve this. Wait? Does sample rate really matter?? It depends what we're talking about. The difference between 44/16 and hi-res FLAC formats (96/24, 192/24, etc.) is a heated flame war for another day. The discussion here is simply about the ability of the V30 to output, natively, through its quad ESS DAC, the exact same sample rate you have in your music file. Why? Because re-sampling creates artifacts as a result of interpolation error, especially when the up-sampled frequency is not a simple multiple of the original. It's perhaps not surprising to discover that most music apps available in the Google Play Store do not support hi-res PCM and DSD via the quad DAC. (But some do - more details below...) However, the unpleasant surprise is that LG made a staggeringly bizarre oversight in the implementation of the V30's DAC, which cannot natively support 44 kHz, 16 bit files. Why is this such a bizarre oversight? Because the overwhelming majority of all digital music available today is in 44/16 format, and this will get up-sampled to 48/16 on most music apps, including the native LG music app. Sensitive IEMs need less power and can expose audible errors in the 16-bit integer representation of gain interpolated as a result of the up-sampling at low volume. These artifacts were first pointed out by @kundica on the main V30 thread (to hear this effect, listen on sensitive IEMs to the opening of Pink Floyd's Dark Side Of The Moon at volume level at or below ~15 via the native LG music app). Luckily, there is a solution to this. The Neutron and UAPP Android apps are capable of playing back all PCM files at their original sample rate - including 44/16 format files. They do this by bit-padding 44/16 files to 44/24 (a process that creates no audible artifacts), which the ESS DAC then processes natively without up-sampling. Neutron's interface can be confusing for new users - it has an awful lot of features and options - but it's able to play back all PCM (44, 48, 96, 192, 384 kHz) at native sample rate, has an awesome parametric EQ and is under intense active development. Support for native playback for 44 kHz and hi-res PCM files is also now available in UAPP (USB Audio Player Pro). This is significant because UAPP also allows streaming via Tidal and the official Tidal Android app will not play back 44/16 files without up-sampling. Both UAPP and Neutron are able to export bit-perfect data via USB-out, for those that want to use external DAC/amps. Spoiler: DSD A very brief background... PCM = pulse code modulation, which is the most common digital audio representation. It simply stores an amplitude value (usually represented as a 16- or 24-bit integer) over a series of discrete points in time, the gap between which defines the sampling frequency, f=1/dt. DSD = direct stream digital, which uses pulse density modulation. Instead of representing amplitude as a function of time, in PDM the amplitude is represented by the density of the pulses. Not everybody is a fan of DSD these days. For example: https://forums.linn.co.uk/bb/showthread.php?tid=23096 The following is a verbatim quote from Rob Watts that addresses some of the technical limitations (as he sees them) of DSD: I'm not here to bash DSD - I have some outstanding DSD recordings, but I suspect the key is just that I have some outstanding DSD recordings. In other words, the recordings themselves are what's most important and it seems that in many hi-res or DSD albums, a little more care was taken with the recording/mixing/mastering process. Moving on from the controversy over the format itself - if you have those files, you still want to be able to play them... DSD files with the .dsf extension can be played back via the stock LG music app or Neutron. Both these apps can play back DSD64 and DSD128 via DoP (DSD over PCM - which is a brilliant little trick that is audibly equivalent to native DSD playback). The latest UAPP update now allows it to do the same. Neutron can even playback DSD256 files (through some software trickery), which the stock LG music app simply refuses to play. Neutron and UAPP can also output bit-perfect DSD over USB to an external DAC. For iso files ripped from SACD, things are a bit more complicated. I know some users have been looking for an app that can handle these files. Neutron can't play iso files directly. Many thanks to @zenmastering for pointing out that UAPP does have some iso file support. A few of us have been testing this. I've not had much luck so far, but YMMV. You may get lucky with UAPP. Other apps like Kamerton are able to play iso files, but convert the audio to 48 kHz PCM. I'll keep updating this section if this situation changes. Spoiler: Bluetooth on the V30 Would you really buy a phone with a 3.5 mm socket, a high-quality DAC and amp, and then by-pass all of this using Bluetooth? If so, you're on the wrong thread. You probably want an iPhone. They're magical. Apparently. And Apple's removal of the headphone socket vastly improves the audio quality and the user experience. According to Jony Ive. In case you hadn't guessed, I'm not a fan of Bluetooth. I do own several Bluetooth headsets - some of them actually sound pretty good, and I understand the convenience factor. However, there's no Bluetooth codec yet developed that can losslessly transmit the files discussed in this post - not even AptX or AptX HD. And even if your headphones and transmitter both support a particular codec, what you'll actually get is the lowest common denominator of each, given the prevailing connection quality; and this could easily drop back to SBC and you'd never know, given the poor audio quality you'd be expecting anyway via Bluetooth. Bluetooth requires you to keep your headphones charged, but still run the risk of them failing at a crucial moment - not just because of the batteries running flat - the headphones can simply become unpaired when connections drop, which is a 100% guarantee at some point; dropouts are a regular occurrence with Bluetooth. BT headphones' built-in DACs tend to be poor, their built-in amps tend to be cheap, the quality of the headphone drivers themselves tends to be sub-par. Bluetooth sound quality is simply no match for the best wired headphones. I'm sure it will be one day, but that's many years in the future. Don't believe Apple's lies. They dropped the headphone jack for one reason only. Money. They want to make more money by selling your their own BT headsets, and they want to make even more money by charging a license fee every time you connect a wired headphone or external DAC, since the only wired connection to the outside world is now Apple MFi proprietary. If you're a V30 owner, you have a really high quality DAC and amp if you simply plug in a good pair of wired headphones P.S Thanks to @VI001101106 for the following tip for BT users: If you have an aptX-HD capable headset, you can 'force' an HD connection in the BT settings once they're paired to the phone. Spoiler: MQA The jury's still out for me on Merdian's Master Quality Authenticated format (MQA). There are several parts to Meridian's technology (https://en.m.wikipedia.org/wiki/Master_Quality_Authenticated) and whether or not you think it makes an audible difference, there is some fascinating technology behind it. Let's get the obvious point out of the way first. Many very smart people do not believe in hi-res anything: https://people.xiph.org/~xiphmont/demo/neil-young.html I think it's also worth mentioning @SomeGuyDude's emphatic and decisive take-down of hi-res recordings. I'm quoting the first part of his post (https://www.head-fi.org/threads/lg-v30.858933/page-126#post-13930854) here verbatim - no syllables changed for effect: "PFfffhhahahahahahaahahah" As you can see, not everybody's convinced by hi-res and MQA only expands on this hi-res revolution/controversy/snakeoil (choose whichever word you want there). From Stereophile: "MQA is a flawed solution to an increasingly archaic problem (compression). Supporting MQA in any way undermines superior non-proprietary technology, and paying for MQA is like hiring someone to rob you." You can find the full article below: http://flip.it/mRmeJv Could MQA have anything to offer? It looks like Meridian are trying to do something in their DACs, but oddly, their treatment of an impulse-response doesn't actually seem to require an MQA file: http://flip.it/vgA24u There are some theoretical outlier arguments for hi-res w.r.t. noise floor on recordings that might be made in the future with much greater precision than anything used currently, played back using TOTL equipment and gain riding, plus the timing of sharp attack transients, but for the most part, it's questionable if even your dog will appreciate hi-res audio, as every part of the chain - including amps, speakers/headphones have to be capable of extending that far and responding to ultra-fast transients. I spoke to Bob Stuart of Meridian about all this a while ago and he gave me a reference to a paper citing a meta-analysis where it was claimed ~52% of people could hear the difference with hi-res music. That's not very compelling. (FYI, 52% is about the same success rate one could have achieved in identifying the hi-res file by simply flipping a coin.) But the tech is interesting, so let's press on... Even if you're a hi-res believer, MQA isn't lossless - it sacrifices noise floor for sample rate in order to be able to fit the hi-res audio into a container not much larger than that of a regular 44/16 CD file. Something has to give with that level of compression. MQA applies lossy compression to data representing frequencies above those of redbook CD (44 kHz). So even if you're a hi-res believer, you're not getting a perfect delivery via MQA. Furthermore, there are some that question the ethics behind MQA - suggesting that it might not benefit any of us (other than Bob Stuart) in the long run: https://www.linn.co.uk/blog/mqa-is-bad-for-music The following is a more recent look at MQA, with many technical references for those interested in reading further: https://www.computeraudiophile.com/...-of-controversies-concerns-and-cautions-r701/ If you've read this far but are still wanting MQA directly on your V30, the official word from Tidal is that their Android app doesn't support it. (Update: 3/1/2018 - it does now.) But this particular rabbit hole goes a bit deeper... Firstly, you can actually play MQA files via the stock LG music app. The USB tool audio_flinger doesn't correctly report MQA output, but a real-time analysis from REW, recording V30 output directly, shows that the LG music app's MQA output does indeed create high-frequency output, beyond that of 44 kHz CD files. (Note that MQA files are designed to play back at 44 kHz when MQA decoding is unavailable in hardware or software, so this makes it difficult - some would argue impossible- to know whether MQA is actually working properly on your device.) The other issue with Tidal is that even though they don't properly curate material in their Android app, it does appear that the entire catalogue is there and accessible - it's just that you can't easily and directly identify which files are MQA via the Tidal app (thanks to @Left Channel for pointing this out). One suggestion has been to bookmark (i.e., add to your playlists) MQA files from the desktop app, and then play them back from the Tidal app. 44/24 FLAC files from Tidal do play back properly (no up-sampling) on the V30 quad DAC, so yes, MQA will sound better What about higher-sampling rates? One major problem with MQA - and all hi-res formats - is the surprising lack of hi-res (> 44kHz) content in most hi-res tracks. Check out this site: http://www.2l.no/hires/ All but one of the recordings listed in the above site have no content at all over 22 kHz. Some have no content over 11 kHz. So it's obviously not a coincidence that the corresponding MQA files are almost the same size as those of redbook CD. This situation isn't uncommon - there are many vendors offering for sale hi-res albums that actually aren't. See for example: https://www.head-fi.org/threads/bandcamp-promotion-thread.648932/page-2#post-13283024 Still feel like handing over large sums of money to re-purchase or stream all your music in hi-res?!? If so, you're actually in luck. Correct Tidal playback of all PCM and MQA files through the V30 DAC is now available via the UAPP app. (This update dropped 4/25/2018.) The official Tidal app also now correctly support hi-res (24-bit and higher sample-rate MQA) through the V30 DAC, if you can find those tracks. However, the Tidal app still does NOT correctly handle 44/16 PCM, which is still a large proportion of Tidal's catalogue. This up-sampling problem is far more significant than MQA, so UAPP is the best choice for Tidal streaming. On the other hand, UAPP doesn't (yet) provide offline storage for Tidal. The Bottom Line: Recommended Music Apps for the LG V30 1. Neutron - for all on-device storage playback, other than MQA. Why? It correctly plays DSD via DoP (up to DSD128 directly and DSD256 with some software trickery) and PCM files (up to 352 kHz) at original sample rate through the internal DAC or via the USB digital-out. Recommended settings: Under the "Audio Hardware" menu, select "Generic Driver" ON,. (which also has a sub-menu: Generic Driver -> Hi-Res Codec = ON, Generic Driver -> Hi-Res Speaker = ON), "Direct USB Driver", "DSD over PCM (DoP)" and "Follow Source Frequency" options. Note that the "Direct USB Driver" option is just for USB output. Using the latest update under Oreo (Android 8), these settings don't need to change. A great tip from @james444 - by default the V30 only has a brightness slider in the pull-down notification shade, but you can configure it to add a volume slider too, by pulling that shade all the way down, selecting "Edit", tapping the top-right hamburger menu, and toggling on "Volume". This is useful, because Neutron doesn't (yet) give you access to the fine-grained volume control when the quad DAC is active. By configuring the shade to have a volume slider, you don't need to leave the Neutron app in order to recover that fine-grained volume control. 2. UAPP - for all on-device storage playback, Google Play music and Tidal streaming. Why? The latest UAPP update now properly supports the V30 DAC for all PCM formats and MQA. USB digital-out works properly for all formats. More information is available here: http://extreamsd.com/index.php/hires-audio-driver Recommended Settings: Under "Settings"->"Internal audio driver", select "HiRes Direct Driver". Under "Settings"->"HiRes Audio"->"HiRes driver flags", toggle on "Direct PCM" and "MQA". N.B. If your V30 is running Oreo (Android 8), you only need to turn on the "MQA" option here. Under "Settings"->"HiRes driver audio format", leave this option as "Auto". Under "Settings"->"HiRes Audio"->"Buffer Size", I recommend using a 600 millisecond buffer length. USB digital-out has a little bug right now in UAPP, which requires you to disable the "HiRes Direct Driver" option to work properly. (Many thanks to @yklee118 for this tip!) The developer is aware of the issue and it will hopefully be fixed in a future release. 3. The stock LG Music app: At this point, there's really no reason to use LG's music app, other than for MQA files stored on-device, which is probably a rare scenario. Why? It cannot play back 44/16 PCM without up-sampling, and this causes artifacts that are easily audible with sensitive IEMs. It also cannot push anything out via USB that isn't re-sampled to 48/16 PCM. 4. Your favorite 3rd party music app: You probably want to give this a miss. Why? If it's not listed above, it's probably safe to assume your app does NOT work properly with the V30 DAC. Audio will still play through the V30's DAC and amp, but everything will be re-sampled to 48/16 PCM. If you're not sure, feel free to post here and if we find another app that does even partially support the V30 DAC, I'll update this post. Happy listening P.S. Update warning! Android 8 (Oreo) caused some problems for the devs. While Neutron and UAPP do seem to be working correctly now on Oreo, I'm finding occasional problems, particularly with UAPP buffering, glitching or freezing. If you experience these issues, please email your log files to the devs!