Hi, I might be wrong here, but if you use an optical cable and configure your sound output to PCM, you are not going to get 5.1 uncompressed sound (this will affect games and movies, but not spotify which actually sends a 2.1 signal out of the ps4).
The reason behind this is that the optical cable does not have enough bandwidth to fit all the audio channels uncompressed.
If you want real 5.1 uncompressed audio mixed by the ps4 (you want this config so the sound of the games and movies makes spatial sense) the only way is to use HDMI and configure your output to PCM (5.1 or 7.1).
If you want 5.1 compressed audio you can select either HDMI or optical (optical can carry compressed 5.1 sound), but you need to select DTS on your audio config. Note that if you select this, the PS4 will compress the audio before sending it to your receiver and the receiver will be in charge of mixing the sound. So spatial sounds might not be 100% accurate. but you still have 5 differentiated channels.
So here is the dilemma, and also the reason why the spotify app is useless on the PS4 if you want to use it as your main source for music.
If you have a 5.1 decent sound system, the logical way to configure your PS4 is connect it thorugh HDMI and select PCM. As I stated above this will give you 5.1 channels of uncompressed audio mixed by the PS4. If you do that, the spotify app (that only supports 2.1) will send sound only to your left and right front speakers of your 5.1 setup. As you can imagine this sounds extremly bad, almost unusable, because those speakers are intended to be spatial speakers. That means that the PS4 is only using 2 out of the 5 channels availabe.
Now, going back to your original post, I do agree that if you select optical + PCM the app sounds great, and the reason behind that is that is sending 2.1 signal uncompressed, so you are forcing PS4 to stereo sound... Your receiver is receiving a 2.1 signal of uncompressed audio and then is mixing the signal with it's own processor, this sounds great!.... BUT! the drawback is that your games and movies will also be in 2.1 (by selecting optical + PCM you have forced the ps4 to stereo), so forget about spatial audio becuse only 2 channels do not make spatial sound.
The PS4 spotify app should be able to identify that you have selected 5.1 on your settings and then mix it's output for a 5.1 setup. This is not being done at the moment so it is sending a dodgy 5.1 signal with 3 silent channels and causing the music to sound like total cr*p.
I know this is a bit difficult to explain but I hope someone from Spotify is reading so they can fix it!
I bag your pardon, my english is very bad but i will try to answer you.
All your technical declarations are 100% correct. BUT...
SORRY - i am a high-end-freak and i explained the BEST WAY to enjoy music (with ps4) ;o)
Every music song is produced in STEREO and in my opinion, it`s not the best way to hear music with a 5.1 system. 5.1 or higher is a very good solution for films (DVD/BR/Stream) or nice games with good multichannel sound. But music sounds much better with 2 speakers (good qualtity) or a 2.1 system. Believe me, my speakers are the Bowers&Wilkens NAUTILUS and when good stereo speakers are your own, you don`t need a 5.1 system. And on the hifi-market exists so many nice speakers.
When user only have a 5.1 system, i approve to change between the inputs on your amp/reviever and use both connecting-systems. the optical input to hear music and switch down your system to 2.1. for games and films use the HDMI-Input. The only problem is, you have to change the audio settings in your ps4 from PCM to BITSTREAM - that`s it - only a few seconds.
The ps4 offers so many posibilites to connect devices - use them :o)))
In my optinion it`s not a spotify problem - at so many problems, it`s a question of components
With that extended explanation I understand your point, and as you stated above that configuration (optical + PCM) will give you the best sound experience for the spotify app; no doubt about it. I agree with you that music is meant to be listen in 2.1, but there are a ton of codecs DTS/Dolby/etc that will mix a 2.1 signal into a 5.1 sound system.Now here is what drives me crazy about this whole thing, and why I believe the app is to blame. I have a modest high-end 5.1 sound system that consists of a marantz receiver, nice Samsung tele, h&k speakers, atv, and my ps4. When using my atv to listen to music, atv sends a 2.1 signal that my receiver interprets correctly as a 2.1 input, then the receiver applies the codec I have set for that source (DTS music) and plays music through all my speakers. If I want to watch a movie, my atv sends a 5.1 Dolby signal and my receiver then mixes it and sends it to the speakers. This is the best scenario, because all the singals correspond with the sources (2.1 for music, 5.1 for movies), basically this gives me the ability to choose how I want to process sound on my receiver. On the ps4, the above does not happen. If I'm playing a stereo source, like the spotify app, my receiver shows me 5.1 channels, so the ps4 is sending 5 channels, but only using 2, the right and left front ones. This is what causes the sound problem, because if you mix 5 channels where only 2 of them have sounds you are going to end up with a pretty poor output. The spotify app should only send 2.1 channels to the receiver, not 5.1 while only using 2.
As you stated, all of this problems can be solved by going stereo on the ps4. having to revert the config back and forth to listen to music or play games is show stopper to me. Luckily Apple music will be out soon, I'll be sure to try it out and if it works ok I'll migrate my stuff over. My atv already knows how to do the trick to change channels on the fly ( 2.1 or 5.1 depending what am I doing). I hate to say this, but I'm considering migrating because I don't believe spotify will ever fix this.
I think mixing into a 5.1 track is an entirely different topic, it could have some negative effect on the quality, but the true problem is that the content itself is fetched in low quality. It's either on Spotify side or the PS4 is somehow restricting background streaming traffic.
I also just checked the PS3 version of Spotify and... the quality is fine. Compared both on the same setup with headphones connected directly to display, both consoles hooked via hdmi cable. PS3 actually sounded on par with desktop version. It's most noticable in songs with lots of high tones. Sounds such as "S" are very scratchy, as someone mentioned before. Low tones are also noticably more shallow.
I'm curious to know, what is your audio config on the PS4 and what type of sound system are you using? Have you tried Optical+PCM? When I used that config the PS4 Spotify app sounded par with the Desktop.
Any workaround dealing with optical is a non-starter for me. My preamp/proc doesn't have a TOSLINK input. But I see no reason why Sony or Spotify (whichever is responsible) can not implement high quality playback via HDMI. HDMI is a more flexible and higher bandwith connection than optical. Not to mention HDMI is much more prevalent. To be honest, I had forgotten that the PS4 even had a TOSLINK connection. I think of it as a dying spec. Probably RCA analog outputs would have been more utilized (but probably more expensive).
Kozzmozz, while you're not going to beat a pair of Nautilus speakers, don't dismiss 5.1 music too quickly. The main problem is that there isn't much well mixed material. Buy a copy of Beck's "Sea Change" on Pure Audio Blu-ray. I bet you'll modify your opinion.
Would you mind giving it a try?. You can configure you PS4 to optical+PCM even if you dont have a toslink cable, and it will send stereo output through your HDMI connection. If you do hear a better output you will realize that what is messing with you audio is the lack of real 2.1 signal. I would really like to have someone else's feedback over this.
Well I just tried and used the optical option (priority set to linear PCM), while actually using an hdmi connection and it still sound the same (aka horrible). All the settings don't matter as it's the app itself that is providing low quality streaming. Fiddling around with settings might give better results for some, but that's your receiver's magic working, nothing more. The streaming itself from the app is low quality. I hope this is not some limitation of how PS4 background apps work and it can be fixed.
I also just experimented with turning on the optical output (even thuogh I am using HDMI). No change in sound quality. It's still crap. But I did notice that when optical is turned off, my proc recognized the signal as 5.1 but (correctly) output the signal thru only the front 2 speakers.
When I turned optical "on" (but using HDMI) the proc recognized the signal as 2.0 and applied some DTS processing, so sound was coming out of at least 4 of the speakers. I turned that setting off and the sound came correctly thru just the front 2 speakers. I never really use sound processing when listening to stereo music sources. I may turn it on for stereo movies and television.