moray james Posted April 8, 2016 Share Posted April 8, 2016 thought that you were going to try your cabinet sealed and damped with fiberglass? Are you wanting to tun lower or higher than the stock passive was tuned for? If lower all you have to do is to add some dead weight to the stock passive. Vents will only eat up cabinet volume which is one of the positives of passives and vents will generate much more noise than the stock passive will which is another positive of passives over vents. You can retune you passive with added weights and some test tones looped on a on a burned disk so you get a long tone. You can experiment with a number of frequencies. You don't need a microphone just the test tones, the adjusting process is simple. 1 Quote Link to comment Share on other sites More sharing options...
JiminSTL Posted April 8, 2016 Share Posted April 8, 2016 $251. But I'll need shipping. The extra dollar should cover it. I feel this thing slipping away . . . . Should have sent a PM and wrapped it up! 2 Quote Link to comment Share on other sites More sharing options...
mustang guy Posted April 8, 2016 Share Posted April 8, 2016 (edited) Great! I've played with ported vs passive. With the same tune, here is what a port vs passive looks like. The driver I used for this was the RSS315HFA-8. The passive was the 12" Dayton with 142.5 grams of weight added to it. Both are tuned to exactly 20Hz: Transfer Function Magnitude: Max SPL with HPF in place at max power before reaching xmax: So far as I can find, you can add mass to the passive to tune lower. With ported you can tune higher _and_ lower, and I don't know how to tune higher with a passive radiator unless perhaps you use a different one. edit: The ported gets to that max SPL with 440 watts, where the passive needed 500 watts. Edited April 8, 2016 by mustang guy 1 Quote Link to comment Share on other sites More sharing options...
moray james Posted April 8, 2016 Share Posted April 8, 2016 Great! I've played with ported vs passive. With the same tune, here is what a port vs passive looks like. The driver I used for this was the RSS315HFA-8: Transfer Function Magnitude: Max SPL with HPF in place at max power before reaching xmax: So far as I can find, you can add mass to the passive to tune lower. With ported you can tune higher _and_ lower. well if you are talking after the fact re tuning yes with vents you can tune up or down by adjusting the length. With a pre tued passive it is easy to add more weight to tune lower but more complicated to lighten the passive but it can usually be done. Both vents and passives are the same and both can be tuned where you want. As I said after the fact adjustments of factory pre tuned passives will be more work. Both systems are reflex tuning. Passives generally produce much less distortion than to vents and passives do not eat up cabinet volume like vents do. Passives cost a lot more than vents do so it is easy to understand why vents are more popular. 1 Quote Link to comment Share on other sites More sharing options...
Matthews Posted April 8, 2016 Author Share Posted April 8, 2016 Moray, I did try it seal and dampened with fiberglass. Sounded horrible! Part of my goal is to rid of the horrible resonance the passive produces (proper term? IDK). Again, may just be me but I do not like passive radiators. They do more harm than good, IMO of course. Last night testing was awesome. Much improvement compared to the passive. I extended the port tube 2 more inches, hoping for a home run this go around with "the mule" Quote Link to comment Share on other sites More sharing options...
Matthews Posted April 8, 2016 Author Share Posted April 8, 2016 Think I hit the nail on the head. Like what I am hearing. Full session, tomorrow 2 Quote Link to comment Share on other sites More sharing options...
JJkizak Posted April 9, 2016 Share Posted April 9, 2016 Oh my God, a re-incarnation of the Philadelphia Experiment. All you need are about 1000 more RSW-15's. JJK Quote Link to comment Share on other sites More sharing options...
moray james Posted April 9, 2016 Share Posted April 9, 2016 Here is what I believe. If you find out what frequency the vent is tuned to you should be able to tune the passive to the same frequency. That will work better than the tube that you are using. However if the tube makes you happy then be happy. Quote Link to comment Share on other sites More sharing options...
Matthews Posted April 9, 2016 Author Share Posted April 9, 2016 Oh my God, a re-incarnation of the Philadelphia Experiment. All you need are about 1000 more RSW-15's. ...but I like looking at it However if the tube makes you happy then be happy. See how I feel about it once the weekend has passed... Quote Link to comment Share on other sites More sharing options...
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