HondaGuy Posted April 15, 2005 Share Posted April 15, 2005 I have a subwoofer enclosure that originally had a 12" Pioneer downfiring 100w per channel DVC home theater subwoofer with a passive amplified design that I've had in my closet for quite some time since the speaker blew, I'm wondering if you can help me replace it with a good sub that would perform well in the enclosure, it's 5/8" MDF with an internal volume of 1.65 Cu-Ft, I'm willing to convert it to a 10" side firing design but the largest I'd beable to go in a side firing config is 10". I don't want to break the bank here but I would be willing to add an amp to it I've been looking at the ones on partsexpress and they seem reasonably priced. Quote Link to comment Share on other sites More sharing options...
dragonfyr Posted April 15, 2005 Share Posted April 15, 2005 Might I suggest using a computer speaker modelling program such as John Murphy's WinSpeakerz or BassBox to reverse engineer the design by matching the enclosure to a driver. You will want to find a driver whose T/S (Thiel/Small) parameters compliment the enclosure in order to provide the proper loading on the driver. Its not too bad, but you may spend a while playing what if. And this can be minimized if you decide what order tuning you prefer, etc. I hope I haven't glossed over too much too lightly. Don't let this scare you! Its not really difficult and you will learn ALOT in the process. And John Murphy's tutorial/book that accompanies the software is a tutorial & handy reference worth the price in itself for the beginner to advanced designer. builder. Its that handy of a reference. Quote Link to comment Share on other sites More sharing options...
HondaGuy Posted April 15, 2005 Author Share Posted April 15, 2005 I used WinISD to plot this speaker http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-185 and It gave pretty good results 32hz at -3db with a nice curve 2.5" port which it came with at a length of 7.8" for a tuning frequency of 29hz And no you didn't scare me at all I know quite a bit about speakers for being quite a noob about them but I just thought I'd head to this forums of knowledgable Klipschers to see if I could get any advice Quote Link to comment Share on other sites More sharing options...
HondaGuy Posted April 15, 2005 Author Share Posted April 15, 2005 I do have another question, I believe there is a formula used to find out if a subwoofer is down fire compatible, would you happen to know it or a website that has it? Quote Link to comment Share on other sites More sharing options...
dragonfyr Posted April 15, 2005 Share Posted April 15, 2005 Normally the loading will not be signifiant as the legs on the cabinet will prevent it. As the pressure is dispersed isotropically into a fluid (air) - SORRY FOLKS!- the pressure should be dispersed in all directions equally and you shouldn't have a problem with loading. Or at lease no more then firing into the air 'sideways'. This should be the case as long as the base 'venting' is equal to or greater then the cone volume displacement. Any one have other facts regarding this? Quote Link to comment Share on other sites More sharing options...
Olorin Posted April 15, 2005 Share Posted April 15, 2005 I think Adire Audio's website (adireaudio.com) has a means to calculate suspension sag so you can find out if a particular woofer can be mounted horizontally. Quote Link to comment Share on other sites More sharing options...
formica Posted April 15, 2005 Share Posted April 15, 2005 ---------------- On 4/15/2005 11:32:25 AM Olorin wrote: I think Adire Audio's website (adireaudio.com) has a means to calculate suspension sag so you can find out if a particular woofer can be mounted horizontally. ---------------- Yup... they do; Sag = Cms * Mms * g where "g" is the acceleration of gravity (9.81 m/s2) and you are looking for less than 5% sag. Full details at http://www.adireaudio.com/Files/TechPapers/DriverOrientation.pdf Rob Quote Link to comment Share on other sites More sharing options...
DrWho Posted April 15, 2005 Share Posted April 15, 2005 PE has a page on it too: http://www.partsexpress.com/resources/downfire.html Quote Link to comment Share on other sites More sharing options...
HondaGuy Posted April 15, 2005 Author Share Posted April 15, 2005 Whoa that down firing calculation is really confusing, can someone help me or tell me if this will work? http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=295-185 Quote Link to comment Share on other sites More sharing options...
formica Posted April 15, 2005 Share Posted April 15, 2005 ---------------- On 4/15/2005 6:46:14 PM HondaGuy wrote: can someone help me or tell me if this will work? ---------------- Ok, without wanting to sound like an a$$... and based on what your 12th grade science teacher said... make sure the units match... you get... F = ma = N = Kg*m/s2 Cms x Mms x G = 0.00032m /(Kg*m/s2) x 0.167Kg x 9.81m/s2 Cms x Mms x G = 0.000503m or 0.502mm of sag. Now we know that the driver has a xmax of about 15mm, so that represents about 3.3% of sag. Looks good to me... you see any typos? Rob Quote Link to comment Share on other sites More sharing options...
HondaGuy Posted April 16, 2005 Author Share Posted April 16, 2005 Is this a good panel amp? http://www.partsexpress.com/pe/showdetl.cfm?&DID=7&Partnumber=300-796 Also I miss measured the box dimensions, yes it is 1.65 cu-ft but I could easily put a 12" sub into side firing or front firing config. So I'm gonna take a vote on this one, what do you all think I should do with the new driver? Cut bottom hole 1/4" larger and put it where the original was? Cover the bottom with a piece of MDF and put the sub firing to the side? Cover the bottom with a piece of MDF and put the sub firing to the front? Quote Link to comment Share on other sites More sharing options...
BobbyT Posted April 20, 2005 Share Posted April 20, 2005 I have that same sub and amp combo in a diy enclosure. They work very well together. You should be very happy. Is your enclosure ported? Quote Link to comment Share on other sites More sharing options...
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