what's the difference between cheap and expensive HDMI cable?

[MrDudeMan]

Originally posted by: spidey07
MrDudeMan,

Very good point. Most people don't realize that it's not 1s and 0s. Just analog to look like it.

I would assume there is some bandwidth/attentuation/crosstalk differences in the cables though and that could make a big differences at longer lengths.

yes, and this is where proper shielding and build quality come into play. if i were to need a very long cable, i would be much more selective of the manufacturer. however, at short distances, it isnt such a big deal as long as the cable meets certain standards.

a lot of the comments in this thread make it seem like the entire world runs on RS-232.

edit: i thought i should add this little tidbit...i saw a gold plated optical cable from monster at a store. that should tell you something...

 

[b0mbrman]

OMFG YOU GET WHAT YOU PAY FOR!

[Edit]

Digital singal = it either gets there or it doesn't.

Yup

 

[Phoenix86]

Originally posted by: mpitts
Digital singal = it either gets there or it doesn't.

No reason to shell out extra cash. As long as the cable works, you won't notice a difference between a $100 and $10 HDMI cable.

QFT

Even with analog it's generally not worth expensive cables, with digital it's pointless.

edit: Yes, there's an analog signal, but if it's not being converted to 1s and 0s you won't get a signal. The cable works or it doesn't.

Most people are running short cables. In a long cable run, cable quality can account for something.

 

[Howard]

Originally posted by: jimbob200521
It's kind of hard to screw up an HDMI cable, as the signal is digital so anything that can carry 1's and 0's should do the trick.

See 4).

http://www.bluejeanscable.com/articles/hdmi-cables.htm

 

[spidey07]

Originally posted by: Phoenix86

Even with analog it's generally not worth expensive cables, with digital it's pointless.

edit: Yes, there's an analog signal, but if it's not being converted to 1s and 0s you won't get a signal. The cable works or it doesn't.

Most people are running short cables. In a long cable run, cable quality can account for something.

Please stop spreading this nonsense. You could have corrupted data in your video stream and never even know it because of error correction.

It's not a "works or doesn't" kind of thing. There is a whole lot more to it.

 

[mrrman]

bought a 33 ft for $50 from monoprice...works great....monster cable is a ripoff because then can rip you off

 

[biggestmuff]

Originally posted by: MrDudeMan

Originally posted by: MrWizzard
mpitts

Digital singal = it either gets there or it doesn't.

QFT

not quite.

Originally posted by: mpitts
Digital singal = it either gets there or it doesn't.

No reason to shell out extra cash. As long as the cable works, you won't notice a difference between a $100 and $10 HDMI cable.

actually that isnt true. the speed at which the signal propogates over the wire has more to do with it than the attenuation properties of the cable itself. as long as the cable is properly shielded and the velocity of propogation is sufficient, then yes, it is a signal and it either gets there or it doesnt, but it isnt always that simple. you are making the design of high accuracy amplifiers and electronics in general seem trivial when it most assuredly is not. the point of this thread is if the cables are worth it or not, and the answer is it depends. monster cables are always overpriced - i can safely say that. however, some cheap cables are exactly that - cheap - and do not deliver. there is no way to know without either testing or buying and experiencing.


everyone saying its carrying 1s or 0s is very mislead. the signals carry a hell of a lot more information than 0 or 5V. how do you think so much data is transferred so quickly over so few wires at not that high of a frequency? the answer is it is not a 1 line, 2 possible state situation all the time. it can work on phase change, several voltage levels for several bits per clock, and noise is a problem even in a digital signal. you realize when you say digital that the actual wave is still sinusoidal, right?

the point of all of this is that if your cable doesnt trasmit the wave at above a certain velocity then the trasmitting and receiving ends will not be in sync and data will be lost. if the receiver is expecting a 25 degree phase shift per bit per clock and the wave is "too slow" then it will read a wrong value and it isnt simply a "digital signal" since each wave could carry as many as 8 to 16 different values, not just 1 and 0.

Good post.

Just because it's digital doesn't mean that the data isn't prone to errors.

 

[Apex]

Originally posted by: spidey07

Originally posted by: Phoenix86

Even with analog it's generally not worth expensive cables, with digital it's pointless.

edit: Yes, there's an analog signal, but if it's not being converted to 1s and 0s you won't get a signal. The cable works or it doesn't.

Most people are running short cables. In a long cable run, cable quality can account for something.

Please stop spreading this nonsense. You could have corrupted data in your video stream and never even know it because of error correction.

It's not a "works or doesn't" kind of thing. There is a whole lot more to it.

Seriously folks, I wish this "works or doesn't digital signal" myth would just curl up and die once and for all.

Oh yeah, while I'm wishing for stuff, I wish the "send in extra money with your speeding ticket, then don't cash the refund check" myth would go away. Thanks!

 

[biggestmuff]

Originally posted by: mpitts
Digital singal = it either gets there or it doesn't.

No reason to shell out extra cash. As long as the cable works, you won't notice a difference between a $100 and $10 HDMI cable.

1. A path can have good connectivity and can be verified with a multi-meter or CTDR/OTDR.
2. Transmit/receive errors can still occur due to faults in the path.
3. Do the hardware devices on each end perform error detection and correction? How well are each of those handled by the hardware?
4. Is the end user able to detect or measure any uncorrectable errors (eyes, ears)?

 

[spidey07]

Originally posted by: biggestmuff

Originally posted by: mpitts
Digital singal = it either gets there or it doesn't.

No reason to shell out extra cash. As long as the cable works, you won't notice a difference between a $100 and $10 HDMI cable.

1. A path can have good connectivity and can be verified with a multi-meter or CTDR/OTDR.
2. Transmit/receive errors can still occur due to faults in the path.
3. Do the hardware devices on each end perform error detection and correction? How well are each of those handled by the hardware?
4. Is the end user able to detect or measure any uncorrectable errors (eyes, ears)?

Thanks again posting useful information. This "digital is digital" crap needs to be dispelled at every opportunity. Especially since were dealing with very high bandwidth that is HDMI. I'm not saying buy expensive cables by any means as a quality cable that does the job it is supposed to isn't expensive. It's just well made - twists, shielding, impedence, bandwidth, etc.

BTW - anybody know the encoding used with HDMI? What are that encoding's strengths/weaknesses? What is the actual baud rate of the encoding?

 

[PottedMeat]

Time Minimized Differential Signaling


http://www.hdmi.org/download/HDMISpecification13a.pdf

 

[mpitts]

Looks like I was wrong. Wouldn't be the first time

 

[Viperoni]

Originally posted by: MrDudeMan

Originally posted by: MrWizzard
mpitts

Digital singal = it either gets there or it doesn't.

QFT

not quite.

Originally posted by: mpitts
Digital singal = it either gets there or it doesn't.

No reason to shell out extra cash. As long as the cable works, you won't notice a difference between a $100 and $10 HDMI cable.

actually that isnt true. the speed at which the signal propogates over the wire has more to do with it than the attenuation properties of the cable itself. as long as the cable is properly shielded and the velocity of propogation is sufficient, then yes, it is a signal and it either gets there or it doesnt, but it isnt always that simple. you are making the design of high accuracy amplifiers and electronics in general seem trivial when it most assuredly is not. the point of this thread is if the cables are worth it or not, and the answer is it depends. monster cables are always overpriced - i can safely say that. however, some cheap cables are exactly that - cheap - and do not deliver. there is no way to know without either testing or buying and experiencing.


everyone saying its carrying 1s or 0s is very mislead. the signals carry a hell of a lot more information than 0 or 5V. how do you think so much data is transferred so quickly over so few wires at not that high of a frequency? the answer is it is not a 1 line, 2 possible state situation all the time. it can work on phase change, several voltage levels for several bits per clock, and noise is a problem even in a digital signal. you realize when you say digital that the actual wave is still sinusoidal, right?

the point of all of this is that if your cable doesnt trasmit the wave at above a certain velocity then the trasmitting and receiving ends will not be in sync and data will be lost. if the receiver is expecting a 25 degree phase shift per bit per clock and the wave is "too slow" then it will read a wrong value and it isnt simply a "digital signal" since each wave could carry as many as 8 to 16 different values, not just 1 and 0.

Excellent post.

 

[gsellis]

Originally posted by: FrankyJunior
Check out http://www.trianglecables.com

I usually get all my cables there and the prices are always great. Monster is just a brand name like Bose. Only people who buy them are the people that don't know any better.

Hey, I was going to say that...

Actually Monster Cable is such a ripoff, Bose is probably embarrassed by how much a factor of "ripoff" Monster out did them by.

And the #1 reason I refuse to go to Best Buy anymore is....

Ding, ding, ding

They push every customer to buy Monster Cable.

 

[oldscubaguy]

The physical interface of a type B HDMI is actally 6 separate differntial pairs for the Video and Audio data (TMDS Data 0:5), 1 diffential pair for the clock, 1 I2C channel (DDC) for communication between source and host, 1 CEC line, 1 Hot plug detect line, and 1 line with +5VDC.


For any of the data channels or the clock channel:

The nominal high-level voltage of the signal is AVcc and the nominal low-level voltage of the signal is (AVcc - Vswing). Since the swing is differential on the pair, the net signal on the pair has a swing twice that of the single-ended signal, or 2??Vswing.
The differential signal swings between positive Vswing and negative Vswing.

This is interpreted as a 1 or a 0 by the reciever. Since there are 6 data channels there are 6 bits of video data for each clock cycle.

So if any of the data channels or the clock signal is corrupted you can have problems.

With that being said - A differential pair it is very robust, has built in noise immunity since any noise that occures usually is canceled out. The problem comes on long runs when the voltage difference between the + and the - of the pair is not large enough for the reciever to detect. That is why they reccomend larger guage cables for long runs.

Something else to keep in mind:

All cable used for HDMI is made in China, in fact only the manufacturers that make custom cable lengths actually assemble them outside of China. Stock length cables are all made in china utilizing the pretty much the same cable - Including Monster.

For short cable runs (15 feet or less) there is no difference. Just make sure that the HDMI cable you purchase states the following:

A) Supports video resolutions up to 1920 x 1080 and data rates to 5Gbps
- This means that it is a Type B cable.

B) HDMI? and HDCP Compliant.
- this means that the design was tested by a certified tesing facility.

C) That it is at least 28AWG on the data and clock lines.

 

[oldscubaguy]

Sorry, a little misinformation there -
Type B is used for Dual-Link applications. Type A has only 3 data channels so it is 3 bits of data for every clock cycle. The Type A cable you want to get should still be rated to Support video resolutions up to 1920 x 1080 and data rates to 5Gbps as I previously stated.

 

[bigrash]

Originally posted by: oldscubaguy
The physical interface of a type B HDMI is actally 6 separate differntial pairs for the Video and Audio data (TMDS Data 0:5), 1 diffential pair for the clock, 1 I2C channel (DDC) for communication between source and host, 1 CEC line, 1 Hot plug detect line, and 1 line with +5VDC.


For any of the data channels or the clock channel:

The nominal high-level voltage of the signal is AVcc and the nominal low-level voltage of the signal is (AVcc - Vswing). Since the swing is differential on the pair, the net signal on the pair has a swing twice that of the single-ended signal, or 2??Vswing.
The differential signal swings between positive Vswing and negative Vswing.

This is interpreted as a 1 or a 0 by the reciever. Since there are 6 data channels there are 6 bits of video data for each clock cycle.

So if any of the data channels or the clock signal is corrupted you can have problems.

With that being said - A differential pair it is very robust, has built in noise immunity since any noise that occures usually is canceled out. The problem comes on long runs when the voltage difference between the + and the - of the pair is not large enough for the reciever to detect. That is why they reccomend larger guage cables for long runs.

Something else to keep in mind:

All cable used for HDMI is made in China, in fact only the manufacturers that make custom cable lengths actually assemble them outside of China. Stock length cables are all made in china utilizing the pretty much the same cable - Including Monster.

For short cable runs (15 feet or less) there is no difference. Just make sure that the HDMI cable you purchase states the following:

A) Supports video resolutions up to 1920 x 1080 and data rates to 5Gbps
- This means that it is a Type B cable.

B) HDMI? and HDCP Compliant.
- this means that the design was tested by a certified tesing facility.

C) That it is at least 28AWG on the data and clock lines.

wow thanks for all that information. finally a 1st post that's very helpful!

 

[oldscubaguy]

The HDMI cables I use are:

http://www.beachaudio.com/product_info.php?products_id=45295&prodid=516-806bk******=sli

The specs for this cable can be found:

http://www.sterenusa.com/bssd/news/NPR_PDF/516-806%20HDMI%20Cables.pdf