Archived from groups: alt.tv.tech.hdtv (
More info?)
"Lew" <notme@notmindspring.com> wrote in message
news:13dk8aa4oj58k.mjcx73vq8b4z.dlg@40tude.net...
> On Thu, 02 Dec 2004 20:12:48 -0500, Jim Gilliland wrote:
>
> > Lew wrote:
> >> On Thu, 02 Dec 2004 19:32:44 GMT, Lew wrote:
> >>
> >>
> >>>In spite of all the complaints about the Samsung audio sync issue, I
bought
> >>>a HLP4663 at Circuit City after being assured the issue had been
resolved.
> >>>
> >>>It hasn't. Video and internal audio lag behind external stereo
speakers on
> >>>non-HD signals. If I play internal and external speakers I get the
echo
> >>>I've heard so much about.
> >>>
> >>>Before taking it back I thought I would call Samsung. They told me
they
> >>>have a new sound board that takes care of it and a tech would call me
to
> >>>schedule a repair. This surprised me since I had heard Samsung
> >>>couldn't/wouldn't fix this problem. I will post a follow up after
Samsung
> >>>calls me back (they said today).
> >>>
> >>>Lew
> >>
> >>
> >> Turns out I talked to Samsung's authorized repair facility in my area,
not
> >> Samsung. Samsung told them: Internal audio is delayed to match video
> >> delay but external audio feed is NOT delayed. Samsung suggests buying
a
> >> new surround sound system with audio delay built in. Translated, if
your
> >> input signal is not HD or progressive scan, (in my case, non-HD Dish
> >> Network), you will have sync problems if you use an external audio
source
> >> such as a stereo or home theater audio system unless your system has
audio
> >> delay.
> >
> > Samsung fixed my set for this problem. They replaced two boards and the
> > problem disappeared. However, my set was an HLN, not an HLP. This fix
> > is available under warranty to any owner - just call Samsung support.
> >
> > Keep in mind that there are many places along the transmission path
> > where the audio and video can lose synchronization. It's quite possible
> > that you are observing a problem that is already in the signal when it
> > reaches you.
> >
> > In any event, good luck getting it straightened out. If it is in the
> > original signal, a delay in your receiver is the only thing that will
> > fix it. Buying a different set won't help.
>
> I never had a sync problem with my old 26" TV and my stereo and they were
> hooked up exactly the same way.
>
> Samsung has offered to replace my sound boards even though they don't
think
> it will help. Maybe I'll call them tomorrow and have them do it anyway.
> If it worked for you, maybe it will work for me. If it doesn't, I have 30
> days to take it back. Thanks for the input.
>
> Lew
Sound sync problems happen with many systems. The problem starts because of
the difference in time between uncompressing DIGITAL video and audio. Since
video takes much longer to uncompress due to it's complexity it takes longer
to display. This was recognized when the HD standard was developed and HD
transmitters delay the sound by a known number of ms and in the standard
there is a known number of ms delay for the TV to delay the sound so that
the sound and picture are in sync.
If the Manufacturer uses a faster CPU/system for their decompression or
manage to develop a faster algorithm they need to reduce the sound delay on
their end and the converse is true. This is why most sound sync problems
occur in the device that is uncompressing the HD signal i.e.: the set top
box or cable box NOT the TV. Customer hear about the sound sync issue and
assume it's the TV. So far, in my experience, most have been the cable box.
Compounding the above is the difference in work that the digital board has
to do with various inputs to buffer and process a signal. The Ant-in and
composite video inputs require more work/time to display a picture than the
component inputs do. So there is a difference in the time delay required
for each input type. Samsung had a fixed delay on their early sets (HLN and
early HLM) and had to release a new digital board that had adjustable sound
delay. Later models (HLP) have this as a service adjustment of between 1-3
ms The Set doesn't have different delay settings for each input type so
there can be a slight defense in sync. We are talking about 1ms here. Only
the most critical gamer with his face in the screen should be bothered by
this. The simple cure is to use the component inputs for everything.