So in english (sorry), it was mentioned that I can use two 2" ports or one 6" port. What should be used and where should they be placed. You mentioned the sizes and 6x6 port. With 8.75" of space, is that too close? Should the port be right in the middle? Sorry for all the silly questions. I need a bit of direction here.
 

According to my numbers, using two 2" ports would still have the air moving a bit faster that I'd prefer (meaning there would be more of a chance for port noise).  I'd instead go with two 2.5" ports (like these http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=260-478) that are 1.5" long -- or better yet two 3.75" ports (like these ) that are 4.75" long.  I'm talking per speaker so you'll need a total of four ports with those options.  That single 6" port would have been nice, but the depth of it looks like it might cause issues.  If you can find someone selling 5" ports then you could go with one of those per speaker (and make them 3" deep).  All that said, you could try the dual 2" ports (since they are 0.75" deep and thus just holes in the wood) first and see how they work -- just position them so you could upgrade them to dual 2.5" or 3.75" ports if need be.   Their location doesn't really matter.

STL:

According to my numbers, using two 2" ports would still have the air moving a bit faster that I'd prefer (meaning there would be more of a chance for port noise).  I'd instead go with two 2.5" ports (like these http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=260-478) that are 1.5" long -- or better yet two 3.75" ports (like these ) that are 4.75" long.  I'm talking per speaker so you'll need a total of four ports with those options.  That single 6" port would have been nice, but the depth of it looks like it might cause issues.  If you can find someone selling 5" ports then you could go with one of those per speaker (and make them 3" deep).  All that said, you could try the dual 2" ports (since they are 0.75" deep and thus just holes in the wood) first and see how they work -- just position them so you could upgrade them to dual 2.5" or 3.75" ports if need be.   Their location doesn't really matter.

I'm sorry. The one you linked to 8.5 inches long. And I cannot find a 3.75 x 4.75 port on the same site. Also, what's funny is you mention I can try 2 in. ports leaving them at the 3/4 in. deep MDF and see how that goes but how in the world would I know if it is right or wrong. I find it interesting there are so many options. How do you know what to choose or what is correct?

You have to cut the ports I linked to the proper length yourself  -- that's just how it is done. 

 
You would know if the 2" ports are wrong if you hear port noise which would be whistling, huffing, or puffing sounds -- in short anything that sounds out of the ordinary.  Of course your ears might be a bit tainted since they're used to hearing the speakers with the backs open.    Just try the dual 2" ports (but like I said space the properly to allow yourself to upgrade to at least the 2.5" ports).  I'm sure the speakers will initially sounds orders of magnitude better, but after that newness wears off you might notice some port noise (and then again you may not).

STL:

You have to cut the ports I linked to the proper length yourself  -- that's just how it is done. 

 HAHA! Ok. I didn't know that

I hear things pretty well but, is this something should be worried about if I can hear it only from a distance?

 

Even if port noise is indeed present they will still sounds better than they do now with backs open, and be aware that port noise does not hurt your speakers themselves in any way.  Just give it a try and report back the results.

mikieboyblue, 

STL:

mikieboyblue, 

So are you still running those Chorus' without backs? 

 Sadly yes (house remodeling get in the way). I hope to get around to making the backs, rewiring, and installing Bob C.'s crossovers soon! I will report back when I have it done. Thanks for asking.
 

 Ok, I am going to revive this nearly year old thread as I have still not gotten around to taking care of this...sign...

So, new question. We were discussing putting two 15 inch MDF discs in place of the passive radiators and possibly adding a port because the passive radiators seem hard to come by. However, will searching for a replacment M&K driver for my father, I cam across these Dayton 15 inch passive radiators and was wondering if that would work as well? 

http://www.partsexpress.com/pe/showdetl.cfm?&Partnumber=295-194

Obviously they would be much more expensive than the MDF route but just courious. I actually have to read this thread again to figure out what I was suppose to be doing!

Thanks,
Mike

I went ahead and modelled it in WinISD...it looks like you might lose just a bit of output at the bottom end, but not much.

White = Stock
Magenta = Dayton PR

Using 2 Dayton PR's actually gets you lined up perfectly, but I'm not sure if you wanna cut extra holes in your cabinet or not.

Whoa, thanks Doc. You and some of the other folks on this forum really amaze me and really make this forum a better place.

I might not always understand every post, but I do learn something each time.

I find it interestesting that putting two of these Dayton 15s in the cabinets actually matches stock. Makes me wish I could get the stock PR.

The main reason why I am still leaning to get a PR is becuase I would rather have the speakers back to their orignal state as oppose to modified with a plug in the back. Who knows...putting the MDF in there is certainly cheaper by many dollars.

mikieboyblue:

...putting the MDF in there is certainly cheaper by many dollars.

STL:

mikieboyblue:

...putting the MDF in there is certainly cheaper by many dollars.

And if done properly, would get you closer to stock than the Dayton PRs. 

 

Yes....properly....I am sure I will be back to post again when I figure out what I was going to do...I have to reread to see if I needed a port or not.