> On Tue, Oct 29, 2013 at 04:38:00PM -0800, rogerx.oss@xxxxxxxxx wrote:
>> On Tue, Oct 29, 2013 at 04:11:38PM -0800, Roger wrote:
>>> On Tue, Oct 29, 2013 at 08:01:35AM +0100, Clemens Ladisch wrote:
>>>Roger wrote:
>>>> On Mon, Oct 28, 2013 at 12:53:34PM +0100, Clemens Ladisch wrote:
>>>>> Roger wrote:
>>>>>> Trying to reduce my left and right channels to 0.5, but am noticing ALSA is
>>>>>> only reading values specified as floating as "0".
>>>>>>
>>>>>> The below should reduce the volume slightly on channels left (0) and right (0),
>>>>>> but it's obvious I'm getting the channel set to zero (0) or off.
>>>>>>
>>>>>> pcm.myHDMI {
>>>>>> type route slave {
>>>>>> pcm "hw:1,7"
>>>>>> format S32_LE
>>>>>> channels 6 }
>>>>>> ttable {
>>>>>> 0.0= 0.9
>>>>>> 1.1= 0.9
>>>>>> 2.4= 1
>>>>>> 3.5= 1
>>>>>> 4.2= 1
>>>>>> 5.3= 1
>>>>>> }
>>>>>> }
>>>>>
>>>>> The ttable entries are floating-point numbers, except when alsa-lib was
>>>>> configured --with-softfloat.
>>>>
>>>> configure:12281: checking for softfloat
>>>> configure:12299: result: no
>>>
>>>What is the output of "aplay -v -D myHDMI something.wav"?
>>
>>
>>$ aplay-hdmi -v -D myHDMIX Music/Mozart/Essential_Mozart-1/01._Allegro_\(from_Eine_kleine_Nachtmusik\,_K525\).wav
>>Playing WAVE 'Music/Mozart/Essential_Mozart-1/01._Allegro_(from_Eine_kleine_Nachtmusik,_K525).wav' : Signed 16 bit Little Endian, Rate 44100 Hz, Stereo
>>Route conversion PCM (sformat=S32_LE)
>> Transformation table:
>> 0 <- 0*0.9
>> 1 <- 1*0.9
>> 2 <- 4
>> 3 <- 5
>> 4 <- 2
>> 5 <- 3
>
Although I haven't resolved this issue with reducing any of the channels of a
PCM 5.1 stream using ttable (and only able to on PCM 2 channel streams), I've
found the reason why I was likely having reduced sound on the center channel,
making the left and right channels sound much too loud.
Although sound engineers sometimes increas loudness, I found my Yamaha RX-V375
PEQ mixer on by default after each initialization using Yamaha's YPAO.
Turning-off the PEQ mixer seems to prevent the left and right channels sounding
too loud while playing PCM 5.1 streams. (Think PEQ or the Enhancer feature
depletes some of the center channel, blending the center channel into the left
and right channels intermittently, in an attempt to create more virtual
speakers.)
Basically, turning-off PEQ mixer and any Enhancer seems to help, albeit
subtely. I've also found HDMI more of a pain then it's worth, and have
reverted to simply using S/PDIF Toslink. To get the PCM 5.1 stream to the
receiver, I'm simply using an asoundrc with pcm.a52 ondemand mixing. (ie. aplay
-D pcm.a52 Some/PCM51/stream.wav).
To further mention, I compared the retail encoded DTS stream (@ 48kHz, 1536
Kbps) to the ALSA a52 encoding (downmixed) from 24 bit PCM 5.1 stream to 16
bit, 48kHz, 640kbps; and the a52 encoded stream sounds much better than the
retail encoded DTS streams! Quiet surprised as I expected just the opposite.
--
Roger
http://rogerx.freeshell.org/
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