Phoenix Gold Phorum

So I recently read a juicy post from the archives on here with group delay with sealed and ported boxes but I got sick of the back and forth bickering/arguing to find out if anyone mentioned a correlation, if any, with box size and cabin gain.

So what if I had a 3 cubic ft gross ported box that yielded 2.25 cubes net tuned at 35 hz after port/sub displacement for a 12" woofer.

Vs

A 1.75 cubic ft gross ported box that yielded 1.25 cubes net tuned at the same 35 hz for a 10" woofer.

We can say the subs have the same resonant frequency, xmax, resistance, power handling, etc, etc. This is a perfect world in a hypothetical situation . So in a large room the woofers would sound identical in their ideal enclosures. Now put them in the same car.

Would having a smaller box give you a deeper sound (or a lower cabin gain) in the car? I know that 1.25 cubic ft wouldn't give much of a difference but I don't actually know so this is why I am asking. Does changing volume in the trunk or cargo area have favorable or adverse effects on subwoofer response? I feel like having more space leftover in your trunk, you would get deeper bass vs having a big ass box take up most of the trunk.

Is this purely to satisfy curiosity, or do you have a real goal in mind? The reason I ask is simply that I don't know the answer, I suspect that it does indeed have an impact, however, there is almost no chance in hell that you will hear any difference. Can you tell a difference when you have a passenger? A suitcase in the back seat? A dead hooker in the trunk? All of these displace more atmosphere than 1.75 ft^3 (unless it's a really small hooker )

I'm curious to hear the answers you get.

Jason

Yes, just to satisfy curiosity. I mean I can hear a difference with a couple of people in the car. About as much of a difference with engine power for acceleration. Subtle but different. I was really just looking to see if there was a clear advantage to use as little space as possible or use up as much space as possible for better sound.

Now now, you may hear a difference if you fill up your small SUV with a ton worth of sand bags. lol.

My guess is...

The larger box would have more output, because the remaining cabin volume would be less with it, and the smaller the listening space, the greater the output would be.

Eric D wrote:My guess is...

The larger box would have more output, because the remaining cabin volume would be less with it, and the smaller the listening space, the greater the output would be.

great point Eric did think of that

The 12" sub moves more air. It will be louder compared to a 10" period. The box and port plays a big role in resonant freq. A bigger box and port allows the deeper bass to come through from the back of the sub. You restrict the port area, you restrict the sound coming out. A smaller box will not play the low, deep, bass as well as a larger box. But, if you go too large of a box, the tuning freq is so low, the upper music freqs will not be heard (say 45hz and up). So, you need a happy medium. I did built a huge box and it only played 32hz and I could not play any music for listening...

As for the cabin area, it doesn't mean much. Since the cabin breaths and flexes, it is not really holding in the sound, (so it is not a box), (seats absorb too). SPL guys will harden their cabin area so it will act like a box... If you stuff your cabin with filler, make sure it does not absorb the sound. It needs to be hard and reflective to match the resonant freq you are going for.

Cabin area have their own resonance freqs. If you put your sub in a larger, musical seal box. Put a mic 1 meter away, in an open area and played test tones at a certain volume level. You will get Db readings through the freq spectrum. Now, take that same box and put in into your car and go through the same test at the same volume levels. You will now find certain freqs to be louder. Those are the resonance freqs of your car. Now build your box accordingly to work off the car's frequencies.

SPL guys will create a 6th order box and make the cabin area, as part of the box. Hence the hard cabin area. Open the window and all hell comes out! But, the cabin is part of the box.

So, what are you going for? SPL or Music.

Thanks for the helpful input guys! I think I wrapped my head around the scenario. I didn't have any goals other than figuring out what changes when adding more displacement to the vehicle. Very slim change. Thanks again guys!

I originally read this post thinking the same subwoofer would be used in two possible sized boxes. Now that I see the question was two different subs, in different sized boxes, my above point does not really apply very much.