[mythtv-users] Life with both ATSC and NTSC tuners

Adam Felson adam.mythtv at thefelsons.us
Sat Aug 13 02:35:25 UTC 2011

On Aug 12, 2011, 7:54 AM, raymond at wagnerrp posted: 

>On 8/12/2011 09:58, Adam Felson wrote: 
>> 1) There doesn't seem to be any way to match the gains of the two tuners. I can attenuate the
>> convertXs >tuners, but not not the HDHRs. Unfortunately it is the HDHRs that are about 10db louder
>> than the convertXs. >Every time I switch from watching an NTSC program to an ATSC program I get
>> blasted by the volume difference. 

>ATSC tuners have no way to control volume, or resolution, or bitrate, or 
>anything. They are a digital tuner, meaning the content is 
>pre-compressed by the transmission source. They merely receive the data 
>stream as it comes to them. That means the ATSC tuner is not 10db 
>louder, but rather than NTSC tuner is 10db quieter. Does your ConvertX 
>have no volume controls? Perhaps you can insert a preamp into the ALSA 
>chain prior to MythTV capturing it.

The NTSC convertx's mixer is at 100%, but still 10db below the ATSC capture devices.
I like your idea of putting in a software preamp in the alsa chain.  It might work.
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