Hi. I want to know if there will be any negative effects, if both ports of parralel 6th order bandpass are very close to each other. Idea is to use bandpass in sedan car, with both ports coming into the car through back seat. So both ports would be about 18-25mm close to each other (port kinda like a nose ), so basicaly one tunel with wall in center making it into two ports. Is this too close? Will they interfere? Every dB counts here so any negative effects by this extreme proximity would be bad. I had no luck in car audio forum, so I hope that some guys here will know for sure 🙂
Thanks in advance.
Thanks in advance.
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There is no fundamental reason it would be a problem. The ports should be adjustable length and you should measure the result if performance is a factor.
The last time I tried an arrangement like that, it sounded great until the trunk and doors were closed. And then, no bass. The issue was not with the subwoofer, but where I chose to locate it. You might want to do some research to see if anyone else had good results locating the subwoofer where you're planning to locate it in your car.
We know that this arrangement works perfect. We built many 4th bandpass enclosures with ports through seat. I can measure frequency response, my friend will be able to measure SPL. So no problems with measuring.
Ok, lets remove car from equation, I just want to know if very close ports fight in 6th order or not. Trunk would be completely sealed of, all bass to interior. It works extremely well with 4th order, so we want to push it more with 6th. Everything is known how it will work in car and what to expect.
Port proximity to each is the only question . So lets talk port, not car or anything
Since port outputs are with phase shift, so when one port sucks air, another blows it out, i wonder if this would introduce any loses, because of them fighting.
We cant test it because there is no easy way to build box with ports far from each other, without destroying car interior parts.
Ok, lets remove car from equation, I just want to know if very close ports fight in 6th order or not. Trunk would be completely sealed of, all bass to interior. It works extremely well with 4th order, so we want to push it more with 6th. Everything is known how it will work in car and what to expect.
Port proximity to each is the only question . So lets talk port, not car or anything
Since port outputs are with phase shift, so when one port sucks air, another blows it out, i wonder if this would introduce any loses, because of them fighting.
We cant test it because there is no easy way to build box with ports far from each other, without destroying car interior parts.
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i posted in your other thread in the car audio section, but since you are more technical in your concerns here, i'll add that if there is an imbalance issue, i would put more effort into preventing that at the equipment itself, and i believe it would be far more evident at the front of the cabin, with outboard porting. in actuality, i would then go one step further and fire the drivers directly at each-other in a shared center chamber, or away from the single port, if angled. however, if you are separating them in case one fails, or plays differently, i'm not seeing anything wrong with that, either, you would pretty much need a failure, or improper setting to crate cancellation.
Back in my retail days, I built (or had built) many of these and tried to place the ports as close to one another as possible. There is a minor mutual coupling effect to be gained in the passband when doing so and nothing negative happens. This advice came from two of the OEMs we worked with. Good luck on your project.
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