STL Posted July 19, 2007 Share Posted July 19, 2007 Anywhere in the 15" MDF disc should suffice as long as you have the depth clearance. Did you ever measure the distance from the back of the woofer magnet to the back of the cabinet? Quote Link to comment Share on other sites More sharing options...
mikieboyblue Posted July 19, 2007 Author Share Posted July 19, 2007 Anywhere in the 15" MDF disc should suffice as long as you have the depth clearance. Did you ever measure the distance from the back of the woofer magnet to the back of the cabinet? No, I will tonight. I left my tools at the house I am remodeling. Quote Link to comment Share on other sites More sharing options...
Marvel Posted July 19, 2007 Share Posted July 19, 2007 You wouldn't have to cut a disk. It could be a square with the ports put in. As long as your can get the ports put in and get the screw holes to attach the board to the back of the cabinet. It' snot like people are going to be looking at it. Bruce Quote Link to comment Share on other sites More sharing options...
mikieboyblue Posted July 20, 2007 Author Share Posted July 20, 2007 Anywhere in the 15" MDF disc should suffice as long as you have the depth clearance. Did you ever measure the distance from the back of the woofer magnet to the back of the cabinet? No, I will tonight. I left my tools at the house I am remodeling. It looks like there is about 8.75 inches. Quote Link to comment Share on other sites More sharing options...
mikieboyblue Posted July 24, 2007 Author Share Posted July 24, 2007 STL: What did you need the distance for? Quote Link to comment Share on other sites More sharing options...
DrWho Posted July 24, 2007 Share Posted July 24, 2007 Ideally, you need to be a port diameter distance away from any boundaries inside the cabinet. You can get away with closer, but it changes the tuning point (basically shifting it lower). Eventually you get to a point where you start constricting the air and then it essentially becomes a lossy sealed cabinet with lots of chuffing/whistling noises. Quote Link to comment Share on other sites More sharing options...
mikieboyblue Posted July 24, 2007 Author Share Posted July 24, 2007 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. Quote Link to comment Share on other sites More sharing options...
STL Posted July 25, 2007 Share Posted July 25, 2007 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. Quote Link to comment Share on other sites More sharing options...
stormin Posted July 25, 2007 Share Posted July 25, 2007 Maybe a little mis-direction but Brian Cheney of VMPS has PR's down to a science. For the price you pay for his products he has real value for a "true" full ranged speaker. I personally prefer my Klipsch and the dynamics of horns but VMPS's are no slouch. And you can change the bass or "Q" with adding or removing mass from his PR's that come loaded from the factory. Quote Link to comment Share on other sites More sharing options...
mikieboyblue Posted July 26, 2007 Author Share Posted July 26, 2007 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? Quote Link to comment Share on other sites More sharing options...
STL Posted July 27, 2007 Share Posted July 27, 2007 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). Quote Link to comment Share on other sites More sharing options...
mikieboyblue Posted July 27, 2007 Author Share Posted July 27, 2007 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? Quote Link to comment Share on other sites More sharing options...
STL Posted July 27, 2007 Share Posted July 27, 2007 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. Quote Link to comment Share on other sites More sharing options...
STL Posted August 17, 2007 Share Posted August 17, 2007 mikieboyblue, So are you still running those Chorus' without backs? Quote Link to comment Share on other sites More sharing options...
mikieboyblue Posted October 29, 2007 Author Share Posted October 29, 2007 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. Quote Link to comment Share on other sites More sharing options...
mikieboyblue Posted September 16, 2008 Author Share Posted September 16, 2008 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 Quote Link to comment Share on other sites More sharing options...
DrWho Posted September 16, 2008 Share Posted September 16, 2008 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. Quote Link to comment Share on other sites More sharing options...
mikieboyblue Posted September 17, 2008 Author Share Posted September 17, 2008 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. Quote Link to comment Share on other sites More sharing options...
STL Posted September 24, 2008 Share Posted September 24, 2008 ...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. Quote Link to comment Share on other sites More sharing options...
mikieboyblue Posted September 24, 2008 Author Share Posted September 24, 2008 ...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. Quote Link to comment Share on other sites More sharing options...
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