How to Resolve these Alsa warnings by /etc/asound.conf?

Examples of Alsa warnings got by many applications (etc Matlab 2016a), which naturally appear in many applications but which differentiation into important and non-important ones has been difficult for me; I keep all warnings important, once I get them so I really would like to silent non-important warnings ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.rear ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.center_lfe ALSA lib pcm.c:2239:(snd_pcm_open_noupdate) Unknown PCM cards.pcm.side ALSA lib pcm_route.c:947:(find_matching_chmap) Found no matching channel map ALSA lib pcm_route.c:947:(find_matching_chmap) Found no matching channel map MathWorks' support service proposes to silent the warnings by Alsa config file /etc/asound.conf. However, I disagree with their policies of giving such warnings in the first place i.e. calling the function audiodevinfo each time when calling sound/soundsc/audioplayer/audiorecorder commands in Matlab 2016a. So I would like to understand how it is good to silent those warnings such that you do not miss any critical piece of information. Open - ignorance - application specific - ... Characteristics of the system - root@masi:/home/masi# less /proc/asound/cards 0 [PCH ]: HDA-Intel - HDA Intel PCH HDA Intel PCH at 0xdf128000 irq 127 Rejected proposals --- 1. Edit /usr/share/alsa/alsa.conf and change # https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=129648 pcm.front cards.pcm.default # original pcm.front cards.pcm.front but issue with Matlab 2. Restart pulse pulseaudio -k 3. Output: unsuccessful, the errors keep coming Matlab 2016a's part --- Answer from MathWork's tech support > These warnings are generated when you execute the "audiodevinfo" function for the first time which is called internally when you execute the "sound/soundsc/audioplayer/audiorecorder" commands. The "audiodevinfo" tries to enumerate all the devices on the system. > > The warnings are generated by the ALSA system libraries and it does not affect the behavior of MATLAB. The cause of this issue is not related to MATLAB. I would like to suggest you to take a look at the ALSA config files such as "/etc/asound.conf" to resolve the warning messages. However, assisting you with editing the ALSA config files would be outside the scope of our Technical Support. I think Matlab should design their product such that you do not get those warnings. It can a mark of bad design if you call such an info function from another function. How to proceed with the design of /etc/asound.conf? Hardware: Asus Zenbook UX303UA OS: Debian 8.5 Linux kernel: 4.6 (backports) Matlab: 2016a, 2016b prerelease Related: How to Configure ALSA in Ubuntu 16.04 for Macbook and Matlab? but for Ubuntu 16.04