enclosure design - need help (4th order)

[Kyle Collier]

Hi, I have a zv5 15 on a vfl 400.1 (3500 watt). its in a ported box tuned at 32 hz right now. thinking about doing a 4th order. not sure how to go about it. I heard 2:1 ratio is the default for these. my box right now is 4.5 cubes, so do I take 4.5 cubes for the ported side and then 2.25 for the sealed side or...? anyone that has any experience with 4th order I could use some input. also is it worth switching from ported to a bandpass box? I was thinking about doing a 6th order but heard there a little harder to design so I figured id stick to building a 4th order for my first time unless a 6th order is going to be that much better. thanks my peeps. bass on

[Triticum Agricolam]

10 minutes ago, Kyle Collier said:

...also is it worth switching from ported to a bandpass box?.....

99% of the time, no it is not worth switching from a ported box to a bandpass box.  There are very specific situations where a bandpass is going to provide better performance.  These are things like truck blowthroughs and cars with a firewalled trunk, where it is very difficult to get the sound into the cabin.  For the majority of installs a ported box is going to get you the best performance.  Now if you want to use a bandwidth box just to try something different and experiment, that's completely reasonable, just understand you aren't going to gain much, if anything, over a well-designed and built ported box.  

When it comes to designing a bandpass box there really aren't any good shortcuts that are going to work well every time.  Things like "ratios" are a good example of the short cuts I'm talking about.  Designing based on a ratio isn't always going to give you bad performance, but its isn't always going to give you good performance either.  Its a poor substitute for actually learning how bandpass boxes work.  

If you want help designed a bandpass box, myself and others can give you recommendations.  

What are your goals for the system?  What vehicle is this going in?  What kind of music do you listen to?

How much port area does your current box have?

[Kyle Collier]

Honestly I'm just trying to get the most out of what I got. I have as I said a zv5 15 on 3500 watts with a yellow top up front and two juice box batteries in the back with a 240 amp alternator and big 3 upgrade. It's in a Ford F-150 extended cab. My box is 4.5 cubes after the displacement of the sub and ports. The box has 2 4 in aero ports each port is around 11.75 in so it's tuned right around 32 hz. one if the reason I was thinking also about bandpass because I see videos of them hitting all sorts of frequencies, leading me to believe the range is more than that of a ported box. Maybe it's missleading tho too because there running crazy amounts of watts and subs. I really like to feel the music. I'm also wondering if I'd benefit from getting another 15. Problem is I'd have to send my current sub back and have them put d1 coils on it so I can run it at one ohm. Another thing I was wondering if getting another sub and running it at the same ohm would make a difference since it'd have the same output from the amp. Thanks for the input

[Kyle Collier]

i like a lot of rap. Mainly just like low hitting bass but when I tuned my box to 30 hz I felt like I missed out on to much on the mid range notes leading me to tune to 32. Although I miss those super low notes, that's why I started thinking bandpass possibly to get the lows but also extend into the mid range notes. Like u said I'm not to educated on how they actually work .

[Triticum Agricolam]

2 hours ago, Kyle Collier said:

Honestly I'm just trying to get the most out of what I got. I have as I said a zv5 15 on 3500 watts with a yellow top up front and two juice box batteries in the back with a 240 amp alternator and big 3 upgrade. It's in a Ford F-150 extended cab. My box is 4.5 cubes after the displacement of the sub and ports. The box has 2 4 in aero ports each port is around 11.75 in so it's tuned right around 32 hz. one if the reason I was thinking also about bandpass because I see videos of them hitting all sorts of frequencies, leading me to believe the range is more than that of a ported box. Maybe it's missleading tho too because there running crazy amounts of watts and subs. I really like to feel the music. I'm also wondering if I'd benefit from getting another 15. Problem is I'd have to send my current sub back and have them put d1 coils on it so I can run it at one ohm. Another thing I was wondering if getting another sub and running it at the same ohm would make a difference since it'd have the same output from the amp. Thanks for the input

I'll be blunt, for what you want to do you don't need/want a bandpass box, you want a GOOD ported box.  What you have now is NOT good at all.  The problem is port area.  Two 4" ports is way, WAY too little port area for the sub you have and the amount of power you are running.  With two 4" ports you might as well be running 350 watts, not 3500.  Sundown recommends 68 sq in of port area and that's on RMS power (2000 watts).  You have about 25 sq in and are running much above RMS power.  If you wanted to stick with an aero port a single 10" port would be ideal (though it will have to be long), or if you wanted to use a slot port, one with at LEAST 75 sq in of port area, and 90 sq in would be better.  

As far bandpass boxes having wider bandwidth, that's half true and it comes at a price.  A bandpass box lets you trade efficiency for bandwidth.  If you want wide bandwidth you have to give up efficiency (and thus max output).  If you want to maximize output, it will cost you bandwidth, everything is a trade-off and there are no free lunches.  Also, trying to judge the performance of a system based on a youtube video is a wasted effort IMHO.  I don't put much faith in what I see/hear from a video.  

My suggestion for you would be to build another ported box, with the proper amount of port area this time.  It will make a WORLD of difference, I promise.  Myself or others here can help you come up with a design if you need any help.

[Joe X]

OP what's your vehicle? any pics? It's rather difficult to hear a 2Hz difference are you certain of the specs of your boxes?