[mythtv-users] low volume with spdif

Christopher Meredith chmeredith at gmail.com
Thu Feb 4 19:23:20 UTC 2010

On Thu, Feb 4, 2010 at 12:11 PM, Kaushik Mallick
<kmallick2000 at hotmail.com> wrote:
> I am running Mythbuntu 9.10 on a Ion 330 motherboard.
> I have the sound output through spdif into my receiver.
> The sound level in MythTV while watching Live TV or recorded shows is low.
> In other words, the sound  coming out through the speakers (and receiver)
> is low compared to any other inputs I have on receiver like Tuner, DVD player etc.
> I hate it because the sound level goes through the roof when I switch from watching
> Myth to listening to radio for example on my receiver.
> As for the device settings, I have the IEC958 unmuted. I understand that
> there is no way to increase the sound level in IEC958. But is there a way
> to level or increase the sound coming out through spdif so that I can make
> it level with other devices?
> Of course this may have nothing to do with MythTV, but here is the sound
> setting I am using on frontend:
> Audio output device:  ALSA:spdif
> Passthrough output device:  ALSA:iec958:(AESO 0x02)
> Max Audio Channels:  Stereo
> Upmix: passive
> Enable AC3 to SPDIF passthrough  CHECKED
> Enable DTS to SPDIF passthrough  CHECKED
> Use internal volume NOT CHECKED
> Aggressive sound  NOT CHECKED

If you're listening to an AC3 audio track, there's nothing you can do.
AC3 passthrough sends the raw audio data straight to the receiver with
no processing and the receiver does all the DAC and processing.
Depending on your recording setup, you could try increasing the volume
on your TV source (e.g. cable box). You could also enable "use
internal volume," then the volume control will work but the tradeoff
is resampling of the audio. If you're not using 5.1 AC3 a lot, it
might be worth it.

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