When I am in a room people have trouble to understand my voice through L5 and they report that there is too much echo. This problem is not present when I am outside. I remember that @amarok had reported muffled voice with too much echo cancellation and then there were changes that fixed this. But in a room echo must be cancelled. How could I fix this issue?
See @dos’s comment about echo here:
The “muffled” aspect that I reported way back when, was before I learned that one has to adjust the Output volume in Sound settings. In this respect, the L5 is more like a computer than an Android or iPhone, so I didn’t expect to have to do that on Day One to get a proper “phone call” optimized sound.
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Sorry, I did not understand. Does this mean that the problem is solved in Byzantium? Or will be solved in Byzantium?
Yeah, I don’t understand the link @dos posted, either, but I take it to indicate that it is, or was, being worked on. Maybe @dos can advise as to the status.
That post was from Mar 9. A patched PulseAudio version that allows echo cancellation to work was uploaded into byzantium on Mar 17 (amber-phone had it much earlier already).
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Still unclear. I am always in Amber. Never switched to Byzantium on L5. People complain about echo when I am in a room. Is this logical? Or it is their impression? Maybe I should decrease the mic level?
I suspect that your call recipients are experiencing a reverb effect, the type of effect that results from an “echoey” room rather than the echo effect typically associated with standard telephony. I doubt that PulseAudio’s echo cancellation is designed to handle any sort of reverb effect at the source input.
I’m of the opinion that the acoustics of a room have a much greater affect on the Librem 5 in regard to call quality than any other phone I’ve had experience with.
The Librem 5 has two internal microphones (one at the top, the other at the bottom), both of which appear to be active during calls, I suspect that if the top one could be disabled during calls it may help reduce the reverb effect that recipients are experiencing.
Wait, this maybe temporarily easy to solve. Is the upper microphone under this little hole at the top part about in the center of the phone? I yes, I may try to cover it with a finger during a call.
About other phones, do they have only one microphone and L5 has two?
Thanks @amarok, so there is indeed a second mic at the top. Hmmm interesting. Samsung S8 has only one mic, but L5 has two! I did not know that until now.
The second mic does not show up in the Settings. Does alsamixer see it? I will try to see if it appears anywhere… and if can be disabled.
But why a mic on the top in the first place? Why purism added a second mic?
Reverb is the right word. Thanks @Loki and it only appears in relatively small rooms.
I just found this possible explanation: https://android.stackexchange.com/questions/90146/why-do-some-android-phones-have-two-microphones-instead-of-one
Very interesting. However I am not sure that this works on L5. Does it? If the reverb is true (and it is not my fantasy) then the second mic is not doing it’s job.
Maybe it is time to bug @dos . Is noise cancellation using the second mic in place already or this is something to be done in the future and currently only reverbs the speech? If not in place yet, maybe duct tape must be used 
…or painter’s tape, for less residue. 
Hi @amarok,
Amos has taken that diagram and put it in the Wiki. It is probably better to reference it there: https://source.puri.sm/Librem5/community-wiki/-/wikis/Frequently%20Asked%20Questions#13-what-are-the-specs-and-physical-diagram-of-the-librem-5 rather than diving into an old topic.
For example, if the diagram needed further changes, I would probably update it only in the Wiki.
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