ported sub box question

[kpc01]

I think I know or have a good idea but on a ported subwoofer box (in this case a slotted port), does all or atleast most of the bass/air come from the port?

I have a 12 in a ported box in my boat under a seat. Its so muffled I'd like to cut a vent and cover it with a nice vent look. The box is situated so that the port would be basically firing right into this exact spot. Does the sub itself put out much of the bass or would that be worthwhile? I know with the seat open it sounds a lot better and think I'm on the right track but want to double check. The vent would be atleast as large as the port and probably a little larger.

[FunFordCobra]

Bass will only pressurize the port on some frequencies depending on your ports tuning. I'd have a box built by a professional because if you get it wrong, its easy to lose output.

In just normal ported boxes

25Hz port - Very very Slow rap, hair tricks, basically useless for any rock'ish music
32hz port - A lot of playability slowed and normal rap, some rock
35 hz port - Friendly to most music, not a lot of high end drum kick for rock
38 hz port- can play all music basically and sound good, new age low end kick
40hz port- mostly rock and country, high end kick
anything 40hz+ I don't see these much except for true SPL competition cars up to 55hz for 1 note burps.

There are also band passes that have amazing output and bandwidth but they are much more complicated to tune. 4th order band pass has high (sealed box with a loading wall) tuning and also has a loading wall (open) or port on the low side that needs tuning. Great bandwidth, but usually have to really overpower them.

A 6th order which is a ported box inside a ported box. They usually can play from 18hz to 55hz+ with authority and runs great on low power. (Ported box with a loading wall)

Regular Ported boxes have a much more narrow bandwidth so you really have to pick what you listen to most and tune from there to get the output you really want, if you go with a regular ported box.

[kpc01]

thanks for the info. I believe this box is tuned at 38hz and this is a jl 12w3. when I turn it on I can feel all the air moving through the port but don't feel much movement from the sub itself. This isn't a high end setup so not trying to break any records but want to get the most out of what I have. I was hoping I could add a vent in front of the port so it fires into the boat itself instead of being shoved under a seat vibrating everything

[FunFordCobra]

A port is more than a hole in a box. If you make any cuts, as is you will lose output. Id have a small custom box made.

[jluv]

A port is more than a hole in a box. If you make any cuts, as is you will lose output. Id have a small custom box made.

I'm reading it as he is considering making a vent in the seat or whatever, not another hole in the box itself. I may be misunderstanding, though. I definitely agree that you don't want to cut another hole in the box.

thanks for the info. I believe this box is tuned at 38hz and this is a jl 12w3. when I turn it on I can feel all the air moving through the port but don't feel much movement from the sub itself. This isn't a high end setup so not trying to break any records but want to get the most out of what I have. I was hoping I could add a vent in front of the port so it fires into the boat itself instead of being shoved under a seat vibrating everything

If you're talking about clearing a path between your ears and the port, because it's all covered up and mufffled now, then yes, that will probably help some. I wouldn't go crazy trying to have the port opening itself playing perfectly through your "vent". Just give the whole thing some breathing room.

[kpc01]

I'm reading it as he is considering making a vent in the seat or whatever, not another hole in the box itself. I may be misunderstanding, though. I definitely agree that you don't want to cut another hole in the box.



If you're talking about clearing a path between your ears and the port, because it's all covered up and mufffled now, then yes, that will probably help some. I wouldn't go crazy trying to have the port opening itself playing perfectly through your "vent". Just give the whole thing some breathing room.

Yes this is correct. I do have a custom box thats been made and tuned. I just want to get the sound out a little better. The port is a rectangle about 2x10" or so (just guessing) and I plan to cut a 5x12 rectangle under the seat and make a grill for it. The idea is just to let the air from the port out rather than muffling it under the seat. I feel like it will help but don't like cutting holes in my boat if its not going to do anything

[jluv]

Yes this is correct. I do have a custom box thats been made and tuned. I just want to get the sound out a little better. The port is a rectangle about 2x10" or so (just guessing) and I plan to cut a 5x12 rectangle under the seat and make a grill for it. The idea is just to let the air from the port out rather than muffling it under the seat. I feel like it will help but don't like cutting holes in my boat if its not going to do anything

If the box is completely closed off right now, making an opening should help you hear more bass. Think of it as standing outside of a vehicle with the doors shut and windows up, and then how much better you can hear it when you open a door. You're probably not going to feel a difference, but you should hear it a little better. I don't even think you need to worry too much about lining up the vent with the port. Just create an opening where the sound can escape whatever compartment you have it in right now.

[EW]

thanks for the info. I believe this box is tuned at 38hz and this is a jl 12w3. when I turn it on I can feel all the air moving through the port but don't feel much movement from the sub itself. This isn't a high end setup so not trying to break any records but want to get the most out of what I have. I was hoping I could add a vent in front of the port so it fires into the boat itself instead of being shoved under a seat vibrating everything

The woofer does not need to move very much. If you are saying that the subwoofer enclosure is sealed up under the seats or in a storage area, then a vent(s) installed in the side of the area the subwoofer is enclosed in will help. Marine stores carry vents that work well/look decent.

https://www.westmarine.com/buy/beckson-marine--cycolac-plastic-scoop-vent--106213?recordNum=1

http://www.defender.com/product.jsp?path=-1|6880|2290139|2290142&id=1240176

[kpc01]

The woofer does not need to move very much. If you are saying that the subwoofer enclosure is sealed up under the seats or in a storage area, then a vent(s) installed in the side of the area the subwoofer is enclosed in will help. Marine stores carry vents that work well/look decent.

https://www.westmarine.com/buy/beckson-marine--cycolac-plastic-scoop-vent--106213?recordNum=1

http://www.defender.com/product.jsp?...142&id=1240176

Thanks for the responses from everyone. I will probably need to hit you up anyways EW about a JL sub and possibly tower speakers. trying to see if I have space to have a custom box made for a JL 10 or if I will need to run the infinite baffle