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Tópico: Dual monitor issue (Help Please) - Page: 1

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Here is my issue.

When doing karaoke, I use my Macbook Pro, NS7 and Virtual DJ with my external HD. My macbook has 2.4ghz with 4Gigs of memory.

I need to get the video onto two monitors. I have my 15 inch monitor for people to view while singing but the club wants me to extend the visuals to a big screen TV that is set up behind me so the entire crowd can see the words to the songs.

I first tried to accomplish this by getting a splitter (Y cable VGA). I came off the macbook into the Y splitter. One cable going to the 15 inch monitor, the other going into the big screen. When I hooked it all up, both screens looked REAL bad. I got waves cascading down the screens and the video would blink in and out. Totally unusable.
When I unplugged either monitor, the video would come in perfect on the remaining monitor.

Seeing that what I was doing simply would not work, I purchased a powered VGA splitter.
I got a "SABRENT 4-Port VGA Vider Splitter"
http://www.tigerdirect.com/applications/SearchTools/item-details.asp?EdpNo=4266222&CatId=466

Supports 350Mhz video bandwidth
Supports video resolutions of up to 2048 x 1536 @ 75Hz
Works with VGA, SVGA and multisync monitors
Enhance video signals for distance up to 210ft. (65m)
Allows one computer to provide simultaneous display on four different monitors

This is what happened when I tried the two monitors with this powered splitter...

The video was able to be seen on both displays without blinking in and out but I still had the waves on both displays. The waves were not as bad but still there and it's simply NOT good enough for me.

What else can I do to correct this problem? What do I need?
 
Mensajes Sun 03 Jul 11 @ 8:50 pm
The waves you describe are a grounding problem. I can't really tell you what to do as it is complicated with so many different devices connected but here is where to start.

Keep in mind that there are dangers with having ungrounded plugs but we need to get some testing done. Try any of these one at a time.

If your laptop power supply is grounded, disconnect the ground using another power cord that you don't mind cutting the third prong off for a test.

Make sure that the audio gear and the two moniotrs/splitter are connected to the same electrical phase of the circuit. Better yet, connect them all temporarily to the same outlet.

Dsiconnect the ground of the first monitor.

Disconnect the ground of the second monitor.

Disconnect the ground of the VGA splitter, if it has one.

One of these should solve your problem. Report back with your findings.

-DGee
 
See this is another reason I went to windows from Mac is for HDMI. You can use a high quality HDMI splitter, http://www.gefen.com/ that can go 1-to-two, 1-to-three, up to like 6 tv's if you want to spend the dough.... even wireless.
Happy & safe 4th to ya!
 
DJECoast wrote :
See this is another reason I went to windows from Mac is for HDMI. You can use a high quality HDMI splitter, http://www.gefen.com/ that can go 1-to-two, 1-to-three, up to like 6 tv's if you want to spend the dough.... even wireless.
Happy & safe 4th to ya!



I don't understand this statement. I have HDMI on my MAC and run HDMI out with no issues.


As for the Ground loop issue there are several things you can do. Once is stated above and trying to find out which ground is off. The second is to use one of these GROUND LOOP INHIBITORS. These are not cheap so it may be best to just use the same circuit as the PC to fix the issue since it could be that different circuits are on different AC phases causing this issue.

Also there are VGA to CAT5 converters on the market that are fairly reasonable. Extron makes one but they are BNC in and BNC out which can cause some problems with getting them connected to everything. There are other ones out there just search for them. You will want to be sure it has isolation for HD15 if you go this route (5 channels or more for RGB and HV). Here are several different choices VGA TO CAT5
 
Which Mac do you have with a HDMI out? I haven't seen a MacBook Pro yet that has HDMI out. If I'm wrong, my bad....
 
Getting further into my setup....

Everything is grounded (3 Prong plugs).

I am using a powered system for sound. 2 bass and 2 tops. All of them are plugged into a power strip. My NS7, Vocopro mics, and Macbook are all plugged in together inside my coffin which is then plugged into the same power strip as the speakers.

The 15" monitor is plugged into a different outlet and the big screen is plugged into yet another outlet.

Again, everything is grounded (3 Prong plugs).

When I plug just the 15" in, I get a great result with no waves, no blinking.
When I plug just the big screen in, I get a great result with no waves, no blinking.
When I connect both, I get the waves.

I'm at my wits end. I would think if it was a grounding issue, I would see it with either monitor, not only when using both at the same time.

What could I be missing or overlooking?
 
DGee wrote :
The waves you describe are a grounding problem. I can't really tell you what to do as it is complicated with so many different devices connected but here is where to start.

Keep in mind that there are dangers with having ungrounded plugs but we need to get some testing done. Try any of these one at a time.

If your laptop power supply is grounded, disconnect the ground using another power cord that you don't mind cutting the third prong off for a test.

Make sure that the audio gear and the two moniotrs/splitter are connected to the same electrical phase of the circuit. Better yet, connect them all temporarily to the same outlet.

Dsiconnect the ground of the first monitor.

Disconnect the ground of the second monitor.

Disconnect the ground of the VGA splitter, if it has one.

One of these should solve your problem. Report back with your findings.

-DGee


Thanks DGee
This seems like a lot to do. What if I just use adapters that are not grounded? The plug connector that has 3 holes for a grounded plug to go into but only 2 prongs to be plugged in to an outlet?

This is assuming that it's a grounding issue. Please see post above this one...
 
Additional update...
The only plug that is not grounded (3 Prong) is the splitter itself. I will go to Home Depo today and get a grounded adapter for it.

Oh, just to add to this...

The Macbook Pro has a perfect display no matter what is connected. The waves only come when I connect the 2nd external monitor and the waves are only on the external monitors NOT the macbook Pro.
 
 
cstoll wrote :
Is the input type to the big TV only available to you in VGA?

If you can go SVideo or Composite then I would look at something like this ...

http://www.meritline.com/vga-to-tv-converter---p-40917.aspx?source=nextaghdac



If I go from VGA to any other connection, I would need to use an additional adapter. The connections on the TV are HDMI, Component video, S video and VGA. I am trying to avoid using too many adapters.

I am going from my MBP to the Powered VGA splitter and from the splitter to the monitor and the TV using two VGA Cables.
 
You can hook-up any of those three connections simultaneously ... it works as a splitter. So you can still go to the monitor with VGA but then go to the TV with the S-Video or Composite.

Also, I would consider changing the resolution value of the TV to match the resolution of the monitor you have connected.
 
DJECoast wrote :
Which Mac do you have with a HDMI out? I haven\'t seen a MacBook Pro yet that has HDMI out. If I\'m wrong, my bad....


You can use this and get HDMI output, I use it all the time and you can pick them up at almost any electronics store.
 
cstoll wrote :
You can hook-up any of those three connections simultaneously ... it works as a splitter. So you can still go to the monitor with VGA but then go to the TV with the S-Video or Composite.

Also, I would consider changing the resolution value of the TV to match the resolution of the monitor you have connected.


I would have to see how to change the resolution of their tv. For that matter I will have to find out how to see the resolution of my monitor.

Would coming from VGA to s-video or composite make any difference over going straight VGA?
 
In my opinion, this is where desktop based systems take the lead over laptops. I have a small desktop unit that has 3 Video cards, giving me 6 individual video outputs. HDMI is the way to go here. I have hooked up as many as 12 screens and 2 projectors, all different makes and models to a single output with no lines whatsoever. This line problem sounds more like a sync issue than a bad ground. TV's and computer displays sometimes have different refresh rates. So if you played with the timing, I bet you could get the TV clear, but then you would have a problem with the monitor. I always used different outputs for tv's and computer monitors. You can have an option to clone desktops for certain outputs and have different timings and resolutions for each. Be careful messing around with the timing on your video card in the lappy. Wrong timings could cook the card...
 
@djcity go to setting from your decktop and lower the output resolution to the extended monitors, if that doesn't work increase it till it's in phase...

Good Luck,

Joey...
 
I agree with Chris about checking our resolution/refresh rate one appears to be in conflict, other than that the unit you are using may not be upto the task.

I run an 8 channel vga splitter (I use to use it for another application) and don't experience those problems when using the same type of set up as yourself.

I also run an in line VGA to composite, S-video converter from the 8 channel box if the bars tv does not have a vga input.

Hope you get it sorted...
 
JoeyKJ wrote :
@djcity go to setting from your decktop and lower the output resolution to the extended monitors, if that doesn't work increase it till it's in phase...

Good Luck,

Joey...


How do I do this on a Macbook Pro?
 
System Preferences > Display on the macbook
 
Sorry I forgot your running Mac now.....this should work if the monitors are not to old...
 
After trying a few things and after having asked both here in this thread an out in the field, I am coming to the conclusion that the problem may be with the strength of the analog VGA signal coming from my Macbook Pro.

I have been told that I should abandon VGA and go with DVI or HDMI.

I was told that the digital signal will not degrade like the analog VGA signal does and that will allow me to use two monitors at the same time without the problems I have been experiencing.

Anyone know if that is true?

If this is indeed the way I need to go then I would have to get a new monitor as the one I have is VGA only.

Any suggestions or views on this post?
 
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