Home theater question: Intermittent "Sparking" noise over new Dolby 5.1 speakers over DVD

[fjorner]

I think I already know that the DVD player is the cause of this problem, but I need some input from the collective hivemind of Anandtech on this issue.

Just bought a brand new RCA receiver with built in Dolby digital 5.1 decoding and six speakers.

Was watching Minority Report last night on DVD and about 2-3 times a minute there would be a louder-than-nominal sound that was like a quick electronic spark.

It was over the speakers and seemed to have no relation to on-screen audio or video.

Changing the DVD from 5.1 to 2-speaker stereo had no effect.

I have noticed it on multiple DVD's.

Turning off the TV had no effect.

Pumping the TV through the speakers does not produce these spark sounds, which leads me to believe it is the DVD player, which was a cheap Daewoo from Sams'.

I have gold-plated RCA cables providing audio from the DVD to the receiver. The DVD has no optical audio output.

So does anyone know what could be causing this? Is it just my poor-quality DVD player? Suggestions? Further tests?

 

[fjorner]

<bump>

 

[nord1899]

Got another DVD player you could try? A PS2 or a XBox or a friends?

 

[T2T III]

I have gold-plated RCA cables providing audio from the DVD to the receiver. The DVD has no optical audio output.

If you're just using the analog (RCA) cables, then you are not sending a digital signal between your DVD player and receiver. Does the DVD player have a digital coax output? Does the receiver have a digital coax input that you could connect it to? The digital coax cables run about $8.00 for a 6' cable at Wal-Mart.

However, as suggested above, you might want to borrow a DVD player from a friend and play some of the same movies on it to see if the issue recreates itself. I'd be willing to bet that it doesn't. Keep us posted.

 

[fjorner]

Haven't tried another DVD player yet. Having trouble finding one to borrow. Hadn't thought of a PS2, although I don't have one that may be easier to try.

The DVD player (cheapo from Sam's) doesn't have anything but standard RCA's.

Before, when I didn't have a Dolby Digital receiver system and a plain old stereo receiver, I had no problems.

 

[ScottyB]

Originally posted by: fjorner
Haven't tried another DVD player yet. Having trouble finding one to borrow. Hadn't thought of a PS2, although I don't have one that may be easier to try.

The DVD player (cheapo from Sam's) doesn't have anything but standard RCA's.

Before, when I didn't have a Dolby Digital receiver system and a plain old stereo receiver, I had no problems.

Upgrade your DVD player to one with digital out for your Dolby Digital speakers.

 

[Pepsi90919]

you didn't notice an orange RCA jack on the back? even my friend's cheapo Apex had one of those.

 

[Howard]

Originally posted by: wje

I have gold-plated RCA cables providing audio from the DVD to the receiver. The DVD has no optical audio output.

If you're just using the analog (RCA) cables, then you are not sending a digital signal between your DVD player and receiver. Does the DVD player have a digital coax output? Does the receiver have a digital coax input that you could connect it to? The digital coax cables run about $8.00 for a 6' cable at Wal-Mart.

However, as suggested above, you might want to borrow a DVD player from a friend and play some of the same movies on it to see if the issue recreates itself. I'd be willing to bet that it doesn't. Keep us posted.

IIRC, all phono cables are the same, unless different connectors are used. Like BNC, RCA or what have you.

 

[T2T III]

Originally posted by: Howard

Originally posted by: wje

I have gold-plated RCA cables providing audio from the DVD to the receiver. The DVD has no optical audio output.

If you're just using the analog (RCA) cables, then you are not sending a digital signal between your DVD player and receiver. Does the DVD player have a digital coax output? Does the receiver have a digital coax input that you could connect it to? The digital coax cables run about $8.00 for a 6' cable at Wal-Mart.

However, as suggested above, you might want to borrow a DVD player from a friend and play some of the same movies on it to see if the issue recreates itself. I'd be willing to bet that it doesn't. Keep us posted.

IIRC, all phono cables are the same, unless different connectors are used. Like BNC, RCA or what have you.

They are not all the same. The digital cables are 75 Ohm cables. You could use a video cable to substitute for a digital coax cable, but you can't use one side of those cheapie RCA cables to substitute for a digital coax cable. All phono cables are NOT the same.

 

[crystal]

To make sure it is your dvd player and not the receiver, plug the dvd directly to the tv and try out some movies. If the problem re-occurred, then you know for sure it is your dvd. Otherwise, it could by your receiver that cause the problem.

 

[fjorner]

I don't believe the receiver is bad because unless its getting signal from from the DVD, it's great. So I'm thinking that the DVD player isn't playing nice with the receiver.

checked- the only thing on the back of my crappy daewoo DVD are the RCA's i'm using, L & R. does have s-video...

guess there's not much more to say about this until i test another DVD, possibly with digital audio

 

[fjorner]

UPDATE-

I put a data disc full of MP3's in my DVD player and played them over the speakers... no sparks.

So how fooked up is this? My DVD player only when playing DVD's creates sparking noises.

 

[Doggiedog]

Make sure you get good cables. Like others have said, not all cables are alike.

I once bought a set of cheapo Radio Shack cables for my digital out and they didn't work. When I switched to a higher quality cable, they worked.

 

[FenrisUlf]

They are not all the same. The digital cables are 75 Ohm cables. You could use a video cable to substitute for a digital coax cable, but you can't use one side of those cheapie RCA cables to substitute for a digital coax cable. All phono cables are NOT the same.

No they are not the same. 75 Ohm cables are for ANALOG video signals. Digital signals should use a good quality RCA cable (sheilded if you want, but probably not necessary). Ones and zeros at 1v. If you think that 75 ohm coax is so good for digital, why does Ethernet, which has a much higher bandwith than Dolby Digital, use UTP? As long as the ones and zeros get down the wire, it doesn't matter. Does a regular RCA cable pull a few out randomly? I don't think so. If you have a great deal of interference, it might make a difference, but then you probably have bigger issues to worry about.

Back on topic: The problem lies with the DVD or with the player (or possibly with each being a little out of spec and causing interference). It's an audio artifact caused by the decompressor in the DVD player. Try a different DVD player to see if it's that DVD. Or try a different Minority Report disk to see if yours might be bad.

 

[T2T III]

Originally posted by: FenrisUlf

They are not all the same. The digital cables are 75 Ohm cables. You could use a video cable to substitute for a digital coax cable, but you can't use one side of those cheapie RCA cables to substitute for a digital coax cable. All phono cables are NOT the same.

No they are not the same. 75 Ohm cables are for ANALOG video signals. Digital signals should use a good quality RCA cable (sheilded if you want, but probably not necessary). Ones and zeros at 1v. If you think that 75 ohm coax is so good for digital, why does Ethernet, which has a much higher bandwith than Dolby Digital, use UTP? As long as the ones and zeros get down the wire, it doesn't matter. Does a regular RCA cable pull a few out randomly? I don't think so. If you have a great deal of interference, it might make a difference, but then you probably have bigger issues to worry about.

Back on topic: The problem lies with the DVD or with the player (or possibly with each being a little out of spec and causing interference). It's an audio artifact caused by the decompressor in the DVD player. Try a different DVD player to see if it's that DVD. Or try a different Minority Report disk to see if yours might be bad.

FenrisUlf,

I will provide you with a proper link when I get home later to show you that Digital Coax cables are 75 Ohm cables. However, please head to Google and search for "75 Ohm Digital Coax" and plenty of hits will show up validating the claim that I have made. Please don't spread the wrong information. Thank you!

 

[FenrisUlf]

Originally posted by: wje
I will provide you with a proper link when I get home later to show you that Digital Coax cables are 75 Ohm cables. However, please head to Google and search for "75 Ohm Digital Coax" and plenty of hits will show up validating the claim that I have made. Please don't spread the wrong information. Thank you!

Sure, because everything you read on the internet is correct.

Digital either works or it doesn't. Only signal degredation beyond the noise threshold will cause digital not to work, unlike analog which can be degraded. It would take truly monumental incompetence to design any digital interconnect that was incapable of passing a digital signal without corruption. Plenty of audio places try to sell "audiophile snake-oil" to the less informed, cables being the most common. Please don't tell me you buy into the Monster Cable or other exotic cable hype. You can pass a DIGITAL signal from a DVD player to the decoder with a pair of paper clips effectively, not that I'd recommend it as a long term soloution.

 

[T2T III]

Please don't tell me you buy into the Monster Cable or other exotic cable hype. You can pass a DIGITAL signal from a DVD player to the decoder with a pair of paper clips effectively, not that I'd recommend it as a long term soloution.

I don't own any Monster Cables. However, I do use proper 75 Ohm cables for my digital coax connections. 😉 - these cables cost only a few $$ more than standard RCA cables which are inferior.

 

[FenrisUlf]

Just please explain to me in EE terms how a 75 ohm cable is better/more effective over a 3 foot DIGITAL interconnect run than a regular set of RCA cables. Either the signal arrives or it doesn't. It's digital, therefore the (extremely) minor variations of the waveform due to the (negligable) capacitence, inductance, or resistance of the wire won't mean squat.

There are only 10 types of people in this world - those who understand digtal and those who don't.

 

[T2T III]

Originally posted by: FenrisUlf
Just please explain to me in EE terms how a 75 ohm cable is better/more effective over a 3 foot DIGITAL interconnect run than a regular set of RCA cables. Either the signal arrives or it doesn't. It's digital, therefore the (extremely) minor variations of the waveform due to the (negligable) capacitence, inductance, or resistance of the wire won't mean squat.

There are only 10 types of people in this world - those who understand digtal and those who don't.

So, where do you classify yourself? I'm about this far -> "" from telling you to STFU. YOU explain to me in EE terms why using a standard interconnect will be sufficient for carrying a sufficient 5, 6 or 7 channels of audio between a DVD player and a receiver. There is a reason that 75 Ohm cables are sold for this connection. You don't have to buy Monster cables. You can buy a $5.00 Radio Shack video cable to accomplish this task. Getting the specific cable is a necessity. I doubt that using a standard RCA inter-connect cable will be able to sufficiently carry the higher bandwith for this connection.

Oh, the link you provided earlier discusses inter-connects. We're not essentially talking inter-connects here. By inter-connects, each cable would carry one signal (+/-) for one channel. That's it. Connections between a DVD player and a receiver require the 75 Ohm digital coax connection because 5, 6 or 7 channels of audio are being sent over in addition to the LFE (Low Frequency Effects) channel. Again, this is much higher bandwith than would be required for your typical inter-connect (e.g. connecting a cassette player to a receiver.)

Please find a sufficient source to back yourself up before commenting further. I would like to see you make your comments over in the Home Theater Forum by indicating a standard RCA cable would be a sufficient digital coax cable replacement for a connection between a DVD player and a receiver. You'd get eaten alive in less than 5 minutes - and I'm not talking about the monster cable zealots either.

Here's a good summary that I've located:

Here are the rules:

All video cables must be made with something called 75 ohm coaxial cable.

All coaxial-digital cables must be made with 75 ohm coax.

(The SPDIF, Sony Phillips Digital Interface Format, used for the coaxial-digital connection on a DVD player was designed with a VIDEO cable in mind).

Audio cables can be made with any of the common impedences such as 50/75/110/300. (No, most of them dont say on the jacket what the impedence is.)

Some people have used audio cables that HAPPEN to be made with 75 ohm coax and now preach that "any RCA cable will work".

Several people have used ordinary RCA audio cables with the wrong impedence and ... it appears to work.

But they noticed that the sound during a movie would drop-out. This happened every minute on one system, about every 15 minutes on another. All these problems were solved by changing the cable to a generic VIDEO cable.

CABLE BUILD QUALITY

I agree with Brian OK to a point. You WANT a cable that maintains a good 75 ohm impedence end-to-end. If you take good coax, and slap generic RCA plugs on the end, you get a mis-mash of impedences. So the plugs are actually the weak point of many cables.

But this is much more of a concern for analog video signals rather than digital.

and another:

The coaxial digital cable needs to be made with something called 75 ohm coax. And hopefully, the RCA plugs are somewhere near this.

All video cables are made with 75 ohm coax.

As long as the budget cable works, is well made without loose plugs, and you dont get drop-outs in the sound every few minutes, it's not worth changing.

and another:

The key is to buy "AV" or "Video" labeled cable to use for a digital cable.

"Video" or "AV" cable is 75 ohm cable, many audio interconnect cables are 50 ohm.

IF the package labeling says "Video" or "AV" cable then you should be fine.

Simply put, standard RCA cables MIGHT work ... for a while. Then, drop-outs will more than likely be experienced. People don't have to run out and buy $39.99 Monster cables to achive a good connection. As I mentioned above, Radio Shack sells 75 Ohm video cables for about $5.99 that will sufficiently do the job. Using standard RCA cables as you suggested for these connections is a big No-No. I believe you OWE me an appology. 😉

 

[fjorner]

Hey guys, thanks for the informative exchange.

I have tried multiple movies now. FOTR, Spiderman, Final Fantasy, Minority Report. All create the noises.

So its gotta be the digital decoder in the DVD. Funny... my previous RCA receiver with just R and L out didn't get these problems. Now, my RCA dolby 5.1 receiver with six speakers has these problems. Unfortanately, it's not an easily replaced component, although the cables are, and I might as well invest in some quality cables. I am using gold-plated RCA's already...