Scorpion0987654 Posted January 11, 2016 Report Share Posted January 11, 2016 Hello, so I have a build in mind for a passive radiator enclosure for the crescendo audio forte 15" I emailed psi audio asking them about what there opinion was and they suggested 2 15" radiators which makes perfect sense and they told me to go with 5.5-6.0 cu ft after the displacement of my subwoofer and both psi radiators and tuning can be as my preference to change by the mass added to the radiators but what im wondering is does anybody have any experience in making passive radiator boxes and does anyone have any suggestions for how I should build this or if you believe you have a better estimate for size of the box in the end im looking a as much sq I can get out of the system as possible for the price im not interested in a dofferent sub or different radiators just need some suggestions Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted January 12, 2016 Report Share Posted January 12, 2016 5.5 - 6.0 cubes is awfully big for a single 15". Have you tried modeling the output in any box simulation software to see what kind of frequency response you are going to get? "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
Joe X Posted January 12, 2016 Report Share Posted January 12, 2016 3.5-4 net is what the manufacturer suggests, anyways the parameters for the PRs are needed to calculate a box. Link to comment Share on other sites More sharing options...
ShadeTreeMechanic Posted January 12, 2016 Report Share Posted January 12, 2016 I thought radiators were to help if the box was too small, like the big bad SMD towers? The highest tuning would be the box with no radiators and go down from there? 91 C350 Centurion conversion ( Four Door One Ton Bronco) 250A Alternator (Second Alternator Coming Soon) G65 AGM Up Front / Two G31 AGM in Back Pioneer 80PRS CT Sounds AT125.2 / CT Sounds 6.5 Strato Pro component Front Stage CT Sounds AT125.2 / Lanzar Pro 8" coax w/compression horn tweeter Rear Fill FSD 5000D 1/2 ohm (SoundQubed 7k Coming Soon) Two HDS315 Four Qubes Each 34hz (Two HDC3.118 and New Box Coming Soon) Link to comment Share on other sites More sharing options...
Triticum Agricolam Posted January 12, 2016 Report Share Posted January 12, 2016 I thought radiators were to help if the box was too small, like the big bad SMD towers? The highest tuning would be the box with no radiators and go down from there? The box with no radiators would be a sealed box, the highest tuning you can get would be just the PRs without any weight added to them. Adding weight lowers the tuning from there. What frequency they start off at with no weight depends on the specs of the PRs and the size of the box. "Nothing prevents people from knowing the truth more than the belief they already know it.""Making bass is easy, making music is the hard part."Builds: Link to comment Share on other sites More sharing options...
Scorpion0987654 Posted January 12, 2016 Author Report Share Posted January 12, 2016 5.5 - 6.0 cubes is awfully big for a single 15". Have you tried modeling the output in any box simulation software to see what kind of frequency response you are going to get? I got the 5.5-6.0 cu ft estimate from psi so I assume there reasonably correct seeing as how it's their radiator and unfortunately my dog has recently chewed through my laptop charger and im left with no computer but friends ones occasionally but I would love to put it in winisd 8 or something it's 2 psi passive radiators 15" and a crescendo forte 15" also I can post full specs of the radiators in just a moment Link to comment Share on other sites More sharing options...
Scorpion0987654 Posted January 12, 2016 Author Report Share Posted January 12, 2016 I thought radiators were to help if the box was too small, like the big bad SMD towers? The highest tuning would be the box with no radiators and go down from there? Yes, to my understanding it is small as compared to the vented enclosure seeing as how a PR takes place of a vent I would compare the box sizes and the pr box would achieve lower, flatter response in a smaller box than with port also never have port noise Link to comment Share on other sites More sharing options...
Scorpion0987654 Posted January 12, 2016 Author Report Share Posted January 12, 2016 T/S Parameters for 15″ Passive Radiator: Fs = 21.5 Hz Qms = 5.65 Sd = 830 cm^2 Vas = 340 L Mms = 295 g Cms = .245 mm/N Xmax = 65mm total Usable excursion = 3″ total Maximum moving mass = 2600 grams Link to comment Share on other sites More sharing options...
ShadeTreeMechanic Posted January 12, 2016 Report Share Posted January 12, 2016 Very interesting. The PR would cause the driven cone to unload more and act like the box is bigger. And give some value of output gain at the same time. I wouldn't know what to do with T/S of a PR but would suspect that some values would aid and some attenuate the corresponding values of the driven cone. I will stay tuned to see if someone will stop by and drop some gold nuggets on us. 91 C350 Centurion conversion ( Four Door One Ton Bronco) 250A Alternator (Second Alternator Coming Soon) G65 AGM Up Front / Two G31 AGM in Back Pioneer 80PRS CT Sounds AT125.2 / CT Sounds 6.5 Strato Pro component Front Stage CT Sounds AT125.2 / Lanzar Pro 8" coax w/compression horn tweeter Rear Fill FSD 5000D 1/2 ohm (SoundQubed 7k Coming Soon) Two HDS315 Four Qubes Each 34hz (Two HDC3.118 and New Box Coming Soon) Link to comment Share on other sites More sharing options...
_paralyzed_ Posted January 12, 2016 Report Share Posted January 12, 2016 5.5 - 6.0 cubes is awfully big for a single 15". Have you tried modeling the output in any box simulation software to see what kind of frequency response you are going to get? I got the 5.5-6.0 cu ft estimate from psi so I assume there reasonably correct seeing as how it's their radiator and unfortunately my dog has recently chewed through my laptop charger and im left with no computer but friends ones occasionally but I would love to put it in winisd 8 or something it's 2 psi passive radiators 15" and a crescendo forte 15" also I can post full specs of the radiators in just a moment The box should be built according to the woofer's specs, not the PR's. Can you also post the woofers T/S parameters? Link to comment Share on other sites More sharing options...
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