posted
you will have a (Vf) Vf - the internal volume of the front chamber of the enclosure and a (VR)Vr - the internal volume of the rear chamber of the enclosure.
you will have a Fb(F) - the frequency that the vent in the front chamber of the enclosure needs to be tuned to
Fb(R) - the frequency that the vent in the rear chamber of the enclosure needs to be tuned to
Passband Hertz means the frequencies that will be allowed to pass through the speaker system
example Passband Hertz of your box could be 65hz to 120hz this means from 20 to 64 and 121 and higher will have little or no output but from 65hz to 120hz will have a increase
this applies to Dual Reflex Bandpass (6th order) Enclosure... Series Tuned Dual Reflex Bandpass Enclosure's is a little different and i'm still learning more about them
so when it comes down to it Dual Reflex Bandpass (6th order) Enclosure might not be the best interest of a spl van cause you are tring to get the single loudest note (hz)... when in fact both sides can not be tuned to the same hz cause canclation will acure(no output)this is why i did a Series Tuned Dual Reflex Bandpass Enclosure because i was able to tune the first and second chamber around the same hz we all know why we hit one note
but don't quote me on this
-------------------- GLASS CITY SOUNDS 419-973-7999
posted
1st....yes you can fit a 6th or 7th order in a trunk if your not trying to use large subs or you iso load them. The only problem your going to run into is the size of your vents aren't going to be very large since your trying to accommodate two chambers. If you want to do it right you'll have to cut your back dash ;(
As far as 4th vs 6th..... this is a question that has always giving me trouble because both are very loud. I think that a 4th order will be louder because you can get your freq up...in my experience in dealing with a 6th order your loudest note is going to be where your rear chamber peaks....So it's basically a ported box with "added" acoustical gain/transfer on the front of the chamber(please take that phrase lighty I know there is more to it, I just don't want to go into detail). Basically the front chamber shifts the tuning of the rear chamber lower than is tuned(which makes is great for daily driving). The front chamber will function and be very loud, but it won't be as loud as the lower tuned rear chamber!! There is no set way of making is loud....it's all trial and error. You just have to see what kinda space your working with and just build. I will tell you that the front port should be wide open with very little depth.....all your gain is from the rear so focus on getting it tuned properly, etc....
I think that a 7th order is the loudest of the bunch. With this setup your chambers don't effect each others tuning as much, you can get a higher peak freq. This also is a trial and error box. I can tell you that you should tune the ports atleast 15hz away from each other, ratio doesn't effect anything except your ports....tuning/size....
I know I haven't gone into great detail, but if you have questions I'm happy to answer.
Robert S. Marks
-------------------- Kicker Car Audio Fi Car Audio Power Acoustik 2002 IdBL stk 3 World Champion
Focus on building a better enclosure
7th Order Boyz Posts: 1544 | From: REPRESENTING SOPCHOPPY | Registered: Aug 2000
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