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I have the Logitech z906 plugged into my PC via optical cable. When I select Device Type as “Optical (S/PDIF)” and make sure passthrough is disabled, I get very muffled audio, and low voices in movies I play. If i enable passthrough, the sound is perfect.
I’d like to get this working without passthrough enabled, since that’s what the audio configuration guide recommends.
Why can’t I get 5.1 working properly?
I don’t think so. I can’t see any recommendation to switch off “passthrough”.
Passthrough is the best option because it sends the original audio stream in the file unaltered to the AVR or sound bar.
Every transformation/transcoding will degrade quality, so you should avoid it whenever possible.
Why does that article repeat like 50 times to not enable it? And also windows volume control doesn’t work with passthrough enabled.
That lies in the nature of passthrough: the data are not changed in any way, which means also: volume is not changed at all
So your response has made me more confused. Let me summarize the issues:
If you could address each of these, I’d appreciate it.
No, it doesn’t say that. It says (my emphasis)
We do not recommend enabling passthrough as the first thing you do. Only do that if you are very well informed about what it entails,
Which is sound advice. Due to the above mentioned circumstance that
The second point is also the reason why passthrough is not enabled by default.
No, I did not imply that. You described the sound above as “muffled”, not as “distorted”.
A muffled sound may be caused by transcoding.
Distortion should not be caused by transcoding.
If you hear distortion, disable “Normalize Downmixed Volume” first thing.
Let’s start with the video file you are using to test it:
What is the original audio format in the file?
No, it doesn’t say that
I was referring more to the repetition of that recommendation throughout the article. The most concerning and confusing bit is at the bottom:
This basically makes it sound like you should never want passthrough on, because Plex processes the audio better. It even talks about that little LED light and stuff. Honestly, I’m not that informed about audio technologies and formats, so maybe I’m way off base. But my feedback to you is this is incredibly confusing. I mean, you could probably dissect the words and try to justify it, but I’m just sharing why I was confused.
You described the sound above as “muffled”, not as “distorted”.
Sorry, I used inconsistent wording. Yes, I meant muffled. Here’s the video/audio info on the episode page:
So what happens if you enable passthrough for DTS and you play this video?
It’s the first thing in the article??
guide does emphasize disabling passthrough seemingly more than important than enabling passthrough.
if pass through works for you, THEN USE IT OMGEEEEEE
As mentioned before, enabling passthrough makes the audio sound perfect. Part of the remaining issue was the confusion from the audio guide. Part is that I don’t like that I can’t control volume via my PC anymore because of passthrough. Due to my set up, I manage my volume via Windows, not my physical speakers. I was hoping that the audio would work perfectly without passthrough enabled, with no muffling, as the audio guide seemed to suggest would happen.
The original audio source is 5.1. My speakers are 5.1. There should be no audio processing, even without passthrough enabled. It’s difficult to understand why this is so complicated, and why this isn’t working as I expect without passthrough enabled. Seems broken to me.
Sorry, that is impossible. A change of volume is processing, too (even if it’s a simple multiplication – but it’s processing nonetheless.)
Windows can only change volume of a decoded audio stream. But the audio stream is never decoded when using passthrough. It is sent in its original DTS format over the optical wire to your Logitech speaker(s). Only the Logitech is decoding it – and is then able to change its volume.
What I meant is the kind of processing that would be undesirable, such as converting 5.1 to stereo or something. Basically, why can’t this happen:
Let’s try this at a different angle: What’s causing the muffled / barely-audible voices? That’s the center channel, right? So why isn’t the center channel being retained as it was originally intended without passthrough enabled?
Hi confirm plex media player is configured to decode and set to 5.1 speakers.
go into your windows sound card properties and makes sure it is configured for 5.1 and for optical out and that is the default audio output.
typically from your soundcard settings you should be able to send test tones out to make sure the speakers are wired and in the correct position.
Windows 10 is a bit weird with optical audio devices. For example, it doesn’t seem to allow me to click “Configure” when I select it:
However, when I perform the audio test, I can hear the chime on each of my speakers, starting with the front left (I think). Most of the guides I find on Google for setting up 5.1, require clicking Configure, but I can’t do that here. I assumed that’s because of the optical cable.
Theoretically, it is do-able.
BUT:
I see. So what is PMP actually doing when you disable passthrough and the audio is 5.1? Essentially:
Is it converting it from 5.1 to stereo despite all these settings? Basically, I can’t understand why we tell Plex the speakers are 5.1 if it isn’t going to work right without passthrough on. So I’m wondering what the no-passthrough logic does.
It appears you are affected by a regression.
I can only advise you to go back to an earlier PMP version
or use passthrough for optimum audio quality.
I have already filed the regression.
Oh, ok. Do you happen to know which version I should roll back to? Also, what caused the sudden change of events?
I can’t tell you exactly. I assume if you still can see the ‘Channels’ selector after having switched to ‘optical’ device type, you should be good.
Sorry, I don’t know.
