I think I can help on this one.
I designed bandpass boxes for customers when I worked tech support and R&D for Savard about half a lifetime ago. I got to see firsthand a very good example of just how effective a good bandpass design can be for SPL, in Lufkin, TX back sometime around '94.
We had one guy in an Astro with 12 of our 15's that hit 151.3.
We also had another guy in a Blazer with 2 of our 12's in a bandpass I'd designed for him. He hit 153.1.
Yes, you read that right, 2 12's in a great box outperformed 12 15's in a mediocre box. It was somewhat embarrassing, because both vehicles were using our woofers, but the guy in the Astro hadn't consulted me.
Here's what you need to know:
The defining characteristic of a 4th order bandpass is that the woofer resides on an internal baffle between a sealed rear chamber and a ported front chamber.
The larger the sealed chamber, the lower the center frequency of the passband.
The larger the ported chamber, the higher the gain at whatever frequency to which you tune it.
If you're looking for a straight SPL burp rig, a 4th or 6th order bandpass might very well be the way to go, as you can get an incredible amount of gain, and in such an application, you won't be very concerned with low frequency extension, so you will likely have a very small sealed chamber. In general, subs that prefer sealed boxes prefer 4th order, and subs that prefer ported prefer 6th order.
Tell me what dimensions you have to work with, and if possible, what the resonant frequency of your vehicle is, and I can design you something to do exactly what you're looking for.
I designed bandpass boxes for customers when I worked tech support and R&D for Savard about half a lifetime ago. I got to see firsthand a very good example of just how effective a good bandpass design can be for SPL, in Lufkin, TX back sometime around '94.
We had one guy in an Astro with 12 of our 15's that hit 151.3.
We also had another guy in a Blazer with 2 of our 12's in a bandpass I'd designed for him. He hit 153.1.
Yes, you read that right, 2 12's in a great box outperformed 12 15's in a mediocre box. It was somewhat embarrassing, because both vehicles were using our woofers, but the guy in the Astro hadn't consulted me.
Here's what you need to know:
The defining characteristic of a 4th order bandpass is that the woofer resides on an internal baffle between a sealed rear chamber and a ported front chamber.
The larger the sealed chamber, the lower the center frequency of the passband.
The larger the ported chamber, the higher the gain at whatever frequency to which you tune it.
If you're looking for a straight SPL burp rig, a 4th or 6th order bandpass might very well be the way to go, as you can get an incredible amount of gain, and in such an application, you won't be very concerned with low frequency extension, so you will likely have a very small sealed chamber. In general, subs that prefer sealed boxes prefer 4th order, and subs that prefer ported prefer 6th order.
Tell me what dimensions you have to work with, and if possible, what the resonant frequency of your vehicle is, and I can design you something to do exactly what you're looking for.
