dull colors after exporting

[dasigndr]

I have a question I hope I can get help and direction on.
I do 95% of my graphic design in corel X6. When I export my files, usually an .eps or .pdf file so that I can print on my HP latex 260 printer or our HP45500 UV flat bed. I always seem to have to reset or change the original colors so that I can get the nice desired color I want.
For example I export a file that has, lets say 3 CMYK, or Pantone spot colour. When I open the file in ONYX it never has the exact same colour thus I have to go into the color changer in ONYX to set the CMYK values.
If I have pantone 294 let's say. WHich is converted to CMYK (100-85.23-22) in corel. However http://rgb.to/pantone/coated/294-c converts it to... CMYK (100-69.7-3).

Either way when I open the file in ONYX to send to print it never has these val;es. They are always different. If it is doing this to my spot / CMYK colours I can just imagine what it is doing to my full colour images.

ANy help is greatly appreciated.

 

[J Hill Designs]

it converts differently per your profile. finding conversions on the web are never correct. who knows what color space/profile/whatever was used when making those conversions

 

[Posterboy]

Pantone colour values aren't consistent between swatch books and websites. If you take that same colour you quoted and searched around you would find multiple definitions of that colour. It is likely that Corel has a different breakdown for the PMS colours than ONYX.
Corel can do poor RGB to CMYK conversions. I've found it best to keep design elements in their native form in Corel and when exporting. Then letting the rip sort it out, or using the preflight tool in Adobe Acrobat Pro to do RGB to CMYK if it is required.
I haven't used ONYX for a long time and I don't remember it that well. I currently use Versaworks. Versaworks, (and likely ONYX) has a colour swatch that you can print out, and swatch you can install into Corel. When I have a client who is after a specific PMS colour, I eyeball match my Pantone watch to my Versaworks swatch, then change the colour in Corel to the Versaworks colour.
ONYX probably has the same thing, the manufacturers pallette is specific to your machine and will give you a more reliable output.
I had a job a few years ago that was a big solid black going on an outdoor marquee at a surfing event. It looked fine inside, but once the sun hit it, the colour was a deep deep green, something about sunlight just brought it out. I tried multiple colour balances but it just kept producing the same deep green. In the end I found and used the manufacturers colour palette, and it essentially told the printer to only use black ink, and the output was perfect.