Home Theater Computers > HDMI or DVI Max Cable Length Without Losing Quality ?
plainman007's Avatar plainman007 05:02 AM 06-27-2009
What's the maximum length i can run a hdmi or dvi cable without losing quality. This is for a pc to projector connection.

Is a DVI connection inferior to that of HDMI ? Other than the fact that sound travels with HDMI ? Or is that DVI ?

Also is there a quality hit when using a DVI to HDMI convertor plug on the end ?

rockytt's Avatar rockytt 06:25 AM 06-27-2009
I'm running 75' w/no problems-
walford's Avatar walford 07:43 AM 06-27-2009
Plain....,
The following links may help you:

http://datapro.net/techinfo/dvi_info.html

http://bluejeanscable.com/articl...n.htm?hdmiinfo

Since the HDMI spec provides for longer cables you would want to have the adapter at the PC end so you can use an HDMI cable instead of a DVI cable. A tight fitting adapter should have no appreciable signal loss.
The DVI (digital video interface) is for video interface as compared to the HDMI( High definition multimedia intrface).
plainman007's Avatar plainman007 10:20 AM 06-27-2009
Thanks to both of you.

Walford > Yes i have the adapter at the pc end and from that adapter the hdmi starts and ends at the PJ. But so far ive just been using about 3 meters. I was going to switch to a 30' length and just wanted to check here before i picked them up.

Also if i dont get such a large length what do i do ? Can multiple lengths be coupled together to form one large length and should i use an adpater or go for a DVI to HDMI cable instead.

understand that I didnt understand your last line.
walford's Avatar walford 10:36 AM 06-27-2009
last line comment: you asked if DVI or HDMI supported audio my last line was ment to say that ony HDMI did since it was multimedia and not Video only.
It appears that a 30' HDMI cable will work fine. The cable vendors that are sponses of this fourm do sell different grades of HDMI cables, some with thicker wire(lower gage) and others that will support higher speed HDMI coming in the future.
I see no reason why you can't end to end connect an HDMI or a DVI cable, Just check at the cable vendor sites to see what they offer or contact their support via e-mail.
plainman007's Avatar plainman007 10:44 AM 06-27-2009
Hi thanks for explaining.

Also shoudl i get a dual link or single link dvi ? I mean do both work with standard ports and do they make a visible quality difference ?



Rockytt > 75' oh my. A single length ? No boosters nothing ? And is this dual link or single link ?

Thanks..
rockytt's Avatar rockytt 11:23 AM 06-27-2009
Here it is
Actually have one end hooked up to a geffen hdmi switcher-but no booster at all. Haven't had a lick of trouble with it
walford's Avatar walford 11:30 AM 06-27-2009
Plain.,,
You should get an HDMI cable it does not support dual link DVI which is the method used to support some resolutions higher then 1080p over DVDI whereas HDMI uses a differnent technique so there is no such thing as a dual link HDMI cable.
I even doubt theat there is such a thing as a dual-link DVI to HDMI adapter to connect your PC to an HDMI cable.
plainman007's Avatar plainman007 03:55 PM 06-27-2009
Thanks Rockytt.

Hi Walford,

I was reffering to the dual link in DVI only. Wasnt reffering to HDMI. Now why i asked this was the cable which i use. Doesnt even use an adaptor. Its a direct One HDMI and one end DVI. So how does one find out if its the superior DVI dual or single link. Or does it mean a DVI to HDMI will not have a dual link or some llimitation like that ?
walford's Avatar walford 05:01 PM 06-27-2009
DVI dual link is not superior to HDMI it just allows some resolutions higher then 1080p or 1080i that are handled in a different way with HDMI.
You would not see any differedc with a standard 1080p TV or display unless it's native resolution higher then 1080p and if it required a dual DVI link.
Use an email to your potential cable suppler to find out if their DVI-HDMI cables meet the DVI spec with the adapter end of the able or it they meet the HDMI spec with adapter at the DVI end.
I reccomend the use of an adapter at thw PC end and a HDMI-HDMI cable so that when you in the future you get a graphics card with built in HDMI support you can just through out the adapter and will not have to buy a new cable.
trailergod's Avatar trailergod 12:18 AM 06-28-2009
my HDMI cable is 10 meteres or about 30 feet... from the Denon receiever to 1080p projector..... no qualityy problems...
plainman007's Avatar plainman007 04:05 AM 06-28-2009
Walford > Your right ill try getting a pure HDMI to HDMI cable and just use it with a DVI Adapter so i can use it as is hen i get a hdmi based card maybe. But over all just considering video alone is hdmi picture quality better than DVI or vice versa ?

Trailergod > Thanks
walford's Avatar walford 06:21 AM 06-28-2009
The DVI video interface is a subset of the HDMI video interface. The adapter just maps the proper pins of the DVI connector to the corresponding pins of the HDMI connector.

Any advantages HDMI has over DVI(such as audio support) can only be provided by a graphics card that actually provides HDMI support and AFAIK only the most recent HDMI 1.3 spec actually provides any advantage for video but the video source would also have to support the enhancements.
plainman007's Avatar plainman007 11:50 AM 06-28-2009
Hi Walford,

What i mean is forget about the additional audio etc. On just picture quality basis which is superior ??

Regards
walford's Avatar walford 01:03 PM 06-28-2009
There is absolutly no difference in PQ since they both use exactly the same digital protocol. The signals are just on different pin numbers since the two connectors are different.
It is like saying if I send a document by FedEX or by UPS will the quality of the printing in the document be better in one then the other. And the answer is no since it is only the delivery method that is different.
nvmarino's Avatar nvmarino 02:22 PM 06-28-2009
Speaking from personal experience, the quality of the cable AND the source can also have an effect on how long your cable runs can be without a booster. One of the A/V setups I deal with has an HDMI cable run of about 50'. Using the same resolution (1080P60), some sources work fine with this cable but other sources flicker and have snow. Adding a Gefen HDMI booster enabled all sources to display at 1080P60 without issue. There's a great writeup over at audioholics evaluating different HDMI cables and signal quality that's definitely worth a read (one thing they didn't mention though was my own personal experience mentioned above - that the source can actually have an impact on cable length as well).

Quick edit - I should add I've had no problems with PC sources and this particular setup (probably used ten different PCs with different video cards from different vendors), only had issues with a few different CE sources.
plainman007's Avatar plainman007 11:49 AM 06-29-2009
Thanks Walford and NVmarino.

Marino > You mean long runs work more stable with the output coming from PC cards ?
nvmarino's Avatar nvmarino 11:03 PM 06-29-2009
Quote:
Originally Posted by plainman007 View Post

Thanks Walford and NVmarino.

Marino > You mean long runs work more stable with the output coming from PC cards ?

I definiltey wouldn't say as a blanket statement PC cards provide a more stable digital video output. There were only one or two devices I had issues with and they were cheapo digital media adapters, probably using the cheapest components possible in their video transmitter electronics. I've got no idea if that's the norm, just my own personal experience.
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