On 10/10/13 18:47, Marc Chamberlin wrote:
I opened the alsamixer, and used F6 to select my internal sound chip (HDA Intel PCH) as you suggested. That gives me a bunch of controls, some of which I understand (Master, Headphon) and many which I do not (PCM, PCM Loop, Front, Surround, S/PDIF, S/PDIF D) That said, I tried to figure out what Front and Surround controls are doing, both in the alsamixer konsole and in the YaST2 Sound/Volume Settings and I got some surprising results! If I set the Surround control, in the Alsamixer, all the way down to 0, AND if I set the Surround control in the YaST2 Sound setting to 50 then I am getting sound out of BOTH my left and right speakers, when I use the KMIX test buttons!!! I have no idea what "Surround" means in this context, in YaST2 it almost seems to be some sort of balance control, but in Alsamixer I simply do not grok it's purpose and meaning.
PCM is the audio stream coming from your application, I believe, I consider it analagous to an "input gain" control. S/PDF and SPDF D are the digital audio out (jack and/or optical) Front, surround (and possibly Rear, centre, ...) are for controlling 3.1 (or 5.1, ... etc) speaker sets ("surround sound" in the TV/cinema sense.) Your laptop can probably drive 3.1 and 5.1 (external) speakers as well as stereo, and the onboard speakers of course.
Second weirdness, this same non-orthogonal behavior is also demonstrated with the Front controls in the Alsamixer and the YaST2 sound controller, If I change the Front control in the YaST2 sound module, it affects the Alsamixer Front control, but not vice-versa. Also, the Front control in the Alsamixer controls the volume levels of my speakers, just like the Master control does, so I do not grok the purpose of having a separate Front control and it seems very confusing to have to adjust both of these controls in order to get any sound out of my speakers. While changes to the Front control in the YaST2 module does affect sound levels, indirectly, it appears to do so by making the Alsamixer Front control change, it can become confusing if the YaST2 Front controller is set to zero, and the Alsamixer Front control is then changed to 100, i.e. the two tools will then be reporting different control levels for the Front speakers!
Your laptop speakers (and external stereo speakers) are the same chanel as the "Front" speakers in a surround set, so when you only have a stereo pait Front and Master are effectively the same, but when more chanels are used Master controlls the overall level, and Front controls the front pair of speakers relative to the others (surround, rear etc...) Check out http://en.wikipedia.org/wiki/5.1 and all should become less muddy Dylan -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org