Newbie question: Unmatched sound and video?

[yoss]

Hi there!

I am new to this forum. Purchased a Yamaha RX-V750RDS AV-receiver about a week ago. That unit is quite nice but also pretty complex to a newbie like me ... So I guess I could need some help from time to time.

One thing nasty I discovered so far is when watching TV and having the TV's sound being processed and amplified by the receiver (instead of outputting it from the TV itself) then the sound is delayed compared to the visual TV-picture. The delay is I'd say roughly about one tenth to a quarter of a second, which is not that enormous but clearly more than enough to register it as some irritating glitch.

I'd like to know: Is that a common effect? Does it take ALL AV-receivers that much time to process let's say DTS neo:6 output from an analog stereo input in a way that the result is a delayed audio? Or is that a special "feature" of my Yamaha receiver?

Thanks
yoss

 

[sjdgpt]

Hi there!

I am new to this forum. Purchased a Yamaha RX-V750RDS AV-receiver about a week ago. That unit is quite nice but also pretty complex to a newbie like me ... So I guess I could need some help from time to time.

One thing nasty I discovered so far is when watching TV and having the TV's sound being processed and amplified by the receiver (instead of outputting it from the TV itself) then the sound is delayed compared to the visual TV-picture. The delay is I'd say roughly about one tenth to a quarter of a second, which is not that enormous but clearly more than enough to register it as some irritating glitch.

I'd like to know: Is that a common effect? Does it take ALL AV-receivers that much time to process let's say DTS neo:6 output from an analog stereo input in a way that the result is a delayed audio? Or is that a special "feature" of my Yamaha receiver?

Thanks
yoss

The delay comes from many sources... the signal must travel from the TV to the receiver, be processed, and then sent to the speakers and hence to your ears. Lots of wire, but the biggest delay may actually be from the speakers to your ears, which if you think about it, your HT speakers are most likely farther from your ears than the TV speakers.


Many receivers have a delay processor for handling video signals from the DVD player to allow the audio signal to catch up. It is possible that you have engaged a such delay within your system, and that is the source of your delay. Any delay added at this stage would be detrimental.

 

[yoss]

The delay comes from many sources... the signal must travel from the TV to the receiver, be processed, and then sent to the speakers and hence to your ears. Lots of wire, but the biggest delay may actually be from the speakers to your ears, which if you think about it, your HT speakers are most likely farther from your ears than the TV speakers.

I understand this. But before, I was using an 8-years old non-digital AV-Receiver in the same environment, which processed the TV-audio to something like "ProLogic" - without any visuable/hearable delay ...

Many receivers have a delay processor for handling video signals from the DVD player to allow the audio signal to catch up. It is possible that you have engaged a such delay within your system [...]

This is a delay processor to delay video, right? But that can't cause my problem here, for I don't use the AV-receiver for handling any video.

I am still uncertain if my problem is a common one with up-to-date AV-receivers (and everybody else owning one just tolerates it) or if my Yamaha unit may have a specific weak point here ...

Thanks for your reply.

 

[yoss]

[...] without any visuable/hearable delay ...

That word has to be «visible» ... Sorry for my poor English ...

Cheers

 

[HowY]

Distance setup for your spekers...

Need to run through the setup again for your speakers

There should be NO delay in processing that's noticed
to the degree you mention... switching is in microseconds

1) Delay introduced with TV when turning off the speaker output?

2) Delay due to the distance from listener to speaker....

Does it do this when in STEREO mode only and not with some DSP?

 

[yoss]

There should be NO delay in processing that's noticed
to the degree you mention...

Now, that's a statement after all!

1) Delay introduced with TV when turning off the speaker output?

You mean a certain delay simply caused by the fact that the TV's speakers have been turned off? Hard to imagine. Besides, the TV is working in the same way as it did before with the old non-digital receiver involved - and as I said, there was no remarkable delay then.

2) Delay due to the distance from listener to speaker....

The distance from center loudspeaker to listener is about 3 meters. Which is about the same value that was detected by automatic set-up.

Does it do this when in STEREO mode only and not with some DSP?

No - the delay is gone or at least strongly reduced. But of course - then the center speaker is not working ...

 

[HowY]

Excellent! You are following me...

If it's NOT doing this in STEREO then it's the DSP's delay

Either the DSP's are BAD chipsets or (more likely) youll
have to play with the DELAY or the DISTANCE in the
DSP configuration.

As to *1) I've seen some sets that introduce a delay
if the main speakers are turned off

And *2) get a tape measure and actually measure your
distances. Most here grab the ol DB meter for more
critical measur'in but I've found a TAPE works within
10%, yet to find a "good" auto setup with a mic etc.

I mentioned the TV because you'd know ifin that was the case
because it would have been a familiar occourance

If it does NOT do this in stereo (no DSP intereference)
there is the answer! it's the timing modes of the DSP

 

[yoss]

Excellent! You are following me...

Well ... trying to.

Either the DSP's are BAD chipsets [...]

The kind of prospect that keeps me sleepless at night

[...] youll have to play with the DELAY or the DISTANCE in the
DSP configuration.

So that would mean to modify what distances the automatic setup had detected - for each speaker? Well, I checked already for the accuracy of the evaluated distances, and they all seem pretty realistic. I would need to find one or more speaker distances in the protokoll of about 20 meters or something to pin-point that one as the problem's cause, right? Well, I will double-check when I get home later.

By the way: I don't have that sort of delay when watching DVDs. The DVD's audio is fed into the receiver via digital audio cable. Speaking of my TV-audio-problem again: here the receiver has to convert A/D, then to do all his DSP calculating and then to convert D/A, right? Maybe just the A/D-conversion is the bottleneck ...

 

[yoss]

I would need to find one or more speaker distances in the protokoll of about 20 meters or something to pin-point that one as the problem's cause, right? Well, I will double-check when I get home later.

Well, didn't find anything weird. The right front speaker is the one with the biggest distance to the listener: 4.2 meters (detected by automatic setup and in reality). So I guess the center speaker, which is the closest one with 2.8 meters distance (detected and real) to the listener, will be delayed to compensate the difference of 1.4 meters. A delay to compensate that distance difference should be around 4/1000 second, right? So that can't be the delay the bothers me.

What now?

(I consider to return the unit to the retailer by now ... To end up with a new one, «featuring» the same delay? )

 

[HowY]

I'll hang with you here... Was hoping some better help than I would assist.

Whats interesting is that its through an analog connection
from the TV to the Recv'r right.

It does NOT do this when in Stereo only when a DSP is enabled.

Stereo analog from TV to analog input on recv'r....

My ONLY other question is weather "surround" is enabled on the TV
(on my box if the surround mode is on when in output mode
it sounds terrible but not delayed)

It's looking to me like it's some inherent delay when processing
analog to digital.

My Onkyo does not display this problem nor a friends HK I played
with last night since he was doing some re-wiring I was foolin'
with analog input from his TV and his DVD palyer and no lagtime.

I've no experience with the yamaha but she's sweet by the spec's

Think you're on the the real issue of A-D conversion throught the DSP

Something to look out for!

Hopefully some folk with Yamaha experience can step in and help

 

[yoss]

I'll hang with you here... Was hoping some better help than I would assist.

Thanks alot anyway.

My ONLY other question is weather "surround" is enabled on the TV (on my box if the surround mode is on when in output mode it sounds terrible but not delayed)

I'll check.

It's looking to me like it's some inherent delay when processing analog to digital.

Guess I'll send an eMail to Yamaha here in Germany to check if they can provide some hints on that.

My Onkyo does not display this problem nor a friends HK I played with last night since he was doing some re-wiring I was foolin' with analog input from his TV and his DVD palyer and no lagtime.

Just watch some life news from CNN or similar with the anchorman addressing the camera directly. Watch the lips and compare that to what your ears are hearing. Or ... better don't


Another question: Do up-to-date AV-receivers have something like a service menu which could be entered by some "secret" combination pressed on your remote - like most TV sets have? Won't use that for solving the delay problem but hoping to be able to modify the receivers behavior when the sound is muted.

 

[yoss]

[...] is weather "surround" is enabled on the TV

Seems to be no way to modify my TV's behavior in terms of different audio modes. Seems to be stereo and that's it. The TV's audio out terminals I am using are the standard red and white cinch sockets, not any "amplified" jacks for external speakers.

Later today I will try to re-set the receiver to factory settings - to check if even then that damned delay will persist.

 

[DSMCasey]

I know this could incur cash, but if you are using cable you could improve the picture and get better sound with digital cable. Not to mention that *if* the TV is delaying the signal, then the cable box would hopefully cut that out since the video and audio signal would be coming directly from the box.

Just a thought.

-Casey

 

[yoss]

Later today I will try to re-set the receiver to factory settings - to check if even then that damned delay will persist.

No improvement ...

Not to mention that *if* the TV is delaying the signal, then the cable box would hopefully cut that out since the video and audio signal would be coming directly from the box.

See, the TV is not causing the delay. As I mentioned before: When using the receiver's stereo mode for instance then the produced sound does match the video. In other words: what audio the TV delivers to the receiver is fine, and is still fine when being reproduced in stereo, or "straight", or "pure direct".