LG LCD 47LH90 - Lip Sync / Audio Delay Problems

inaba116 · Post by **inaba116** » Sun Aug 30, 2009 2:55 pm

I am using an HDMI cable from my Comcast HD cable box to my LG LCD 1080P TV and am getting sound lag on certain channels. Could this be the HDMI cable? The cable box? My TV?

Richard · Post by **Richard** » Mon Aug 31, 2009 11:15 am

If it's just certain channels it sure sounds like a problem with your cable system and/or cable box. Everything fine with other HDMI sources?

inaba116 · Post by **inaba116** » Mon Aug 31, 2009 11:36 am

I do not think it is the cable box because if I run normal red and white audio cables from the cable box to some speakers there is no delay. Since I have sound running to external speakers (via red/white cables) and to the TV speakers (via HDMI) I can have both sources playing the audio simultaneously and there is definite lag coming from the HDMI audio.

Richard · Post by **Richard** » Mon Aug 31, 2009 12:16 pm

All digital displays made over the last few years incorporate an audio delay circuit for both digital and analog audio inputs to compensate for the time delay created by the video processing circuit. Due to the variety fo technologies still used this delay should occur at the display. Most current A/V receivers include a delay adjustment to get the that audio in sync with the video. The technical term is lip sync.

While I have not tested this... if you take the audio out of any source as analog into an A/V receiver or amp while running HDMI to your TV and use the TV speakers at the same time you may very well have a delay because the TV will delay the audio to prevent or reduce a lip sync problem with the delayed video (due to video processing). This is not recommended for a multitude of reasons and while this worked for decades with the old TV system and analog display technology you may easily run into problems with digital technology - you need to use either the TV speakers or the A/V receiver, not both. It sounds like you are using both yet...

You say this only occurs on certain channels.

It appears you do not have another HDMI source product to verify what is going on.

The only other possibility, and extremely slight, is a firmware update from LG. Sorry to tell you but you may find discussing that much less getting it from LG like pulling teeth.

My guess says it's the cable box/cable company.

eliwhitney · Post by **eliwhitney** » Thu Oct 01, 2009 3:37 am

Hello inaba . .

"Splurge" . . . treat yourself as an early Holiday Gift, etc., to an "inexpensive" Surround System, connecting it to that Cable Box coaxial digital out or with a Toslink optical ... turning OFF the TVs internal Audio altogether as Richard said .... and you WILL be amazed at what you have been otherwise missing !

NOT necessary to spend .. "more-than-the-HDTV" .. either!

The current offering of ONKYO HT-S5200 .. {or, even Sony's HT-SS360,as a decidedly-second choice} .. have been found to provide quite satisfactory results for an economical outlay!

No ... "complex installation" ... whatever!

everett

{link} = http://www.amazon.com/Onkyo-HT-S5200-7- ... 80&sr=1-51

[ under $500, no tax except NY + KY & free shipping]

cochese · Post by **cochese** » Tue Oct 13, 2009 8:57 pm

I too have an LG 47LH-90 and I am having the same exact problem. It has been driving me nuts! I use Brighthouse cable with a HD DVR cable box. RGB (composite) has no audio lag. I have attached a smaller HDTV (does not do 1080P) but I do not get the lag. I really feel it is the LG TV causing the problems and I would like to know your model/type. I am going to contact LG tomorrow. Of note however is that it does NOT happen on all channels and I have a Blue Ray DVD that uses HDMI and no audio lag there either. It is driving me bonkers!

Thanks

CoChese

cochese · Post by **cochese** » Thu Oct 15, 2009 8:05 pm

I contacted LG support and they stated they have others who have complained about "lip-sync" problems while using a cable box and HDMI. They asked me numerous questions and stated they have developed software to fix the problem. I answered their questions and I am awaiting a response to a link to allow me to upgrade the firmware in the TV to fix the lag.

I'll let ya know what they say.

CoChese

inaba116 · Post by **inaba116** » Thu Oct 15, 2009 8:14 pm

'I am awaiting a response to a link to allow me to upgrade the firmware in the TV to fix the lag."

Thats good news. I contacted them almost a month ago and didn't get much help. I guess they have since realized the problem and developed a solution. Please do let me know when you hear something back from them. Thanks!

Richard · Post by **Richard** » Fri Oct 16, 2009 1:11 pm

inaba116,

It would be very helpful to the topic of this thread if you would provide the model number of your display.

Thanks

inaba116 · Post by **inaba116** » Fri Oct 16, 2009 3:13 pm

Yeah, no prob. It is a LG 42LH30.

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