Need a little help with custom box please.

[Scotnemily]

I am thinking about building a custom box for either 2 8"s or 2 10"s. Probably CT sounds Meso series. Also thinking about soundqubed, and DC audio. Depending on what I can get to work best with this box. The box will be going into a 2001 740il BMW. I want to keep the box as small as possible, within reason. I want the speakers and ports to blow through my ski pass through from trunk into the interior of the car. I am not sure if my port in my design will work or not. box and port size can be tweaked this is just a rough sketch of what I am thinking. Box is limited to 32 inches wide and 15 tall I think.

I am open to different designs too, but want to focus the subs and port through the ski pass through. thanks

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[BOOMINGRANDPA 5,000+ posts]

wow make me 1 like that lol.. shredder or jeff may help u later..

 

[Scotnemily]

Well I am not sure if anyone would even want one like this. The port design might **** and overall the idea might ****. for a concept I liked it, but in the real world it might turn out to be either infeasible or just total crap. I have been out of this stuff for a long time and have forgotten a lot about car audio and design. I know nothing about these new high excursion/ high power speakers. back in the day I was pushing a lot of power at 1/2 ohm, now not so much.

 

[Popwarhomie 5,000+ posts]

I would recommend a 4th order if your trying to go through the ski pass. But with a 4th its not really going to be "small"

 

[Scotnemily]

Thanks. I was thinking that at first also until I realized I wouldn't have a trunk left for anything else.

 

[Scotnemily]

Would this port be ok? Or is 1.5 inches wide just to small. I also read that I should keep the ratio smaller than what I have it now. Right now I think the box is around 1.25 cu ft per speaker, minus what ever the speaker displacement would be. Would it be better to change the design and have the ports starting towards the top and coming drown and out between the subs. Almost the opposite of what I am showing here for the port. I can mock it up and post that for clarity if needed. Thanks!!

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[tymoto21 10+ year member]

That is like a messed up 6th order

If you flipped the sub baffles around facing the back side of the box you could seal them and have a 4th order that would give better results

So 2 small sealed boxes on either side of a large port, then tune the opening into the car

 

[Boomin_tahoe 5,000+ posts]

That design kinda reminds me of what JL Audio offers with their HO and other loaded enclosures.

 

[Scotnemily]

Do you mean something more like this?

This box is 32x20 and inside is 13.25 tall. I am giving each 10" sub 1.36 cu ft before speaker volume. From everything I have read about bandpass, I would need the space the speakers are firing in to be larger than the space the speakers are using. a min of a 2:1 ratio. I also understand this in not a 6th order bandpass, as I don't have the ports. Not sure where to put them and how big to make them. this box is already larger than I wanted but I could go to this size. I wouldn't want to go much larger though. I may have to give up on the ski passthrough and just have them shooting towards the front of the car. I wanted to keep the trunk mostly sealed off from the speakers and ports. I didn't want the loud trunk rattle on the outside of the car.

As a side note I emailed that original design to soundqubed asking about how the HDS 3.1 10" would work with that box. They replied, "That's a nice series tuned enclosure! The HDS3.110 would work great in that application." while I am sure it would work, I seriously doubt that it is Ideal as-is for that sub and I am sure if would be a lot better tweaked. I felt more that they were blowing smoke my way.

 

[Scotnemily]

Ok I think I am going to make this simple. I think I am going to just use 2 HDC3.110 dual 1ohm in a ported box. I think I want about 1.5 net per sub, and will be pushing 800-1200rms to each.

 

[BOOMINGRANDPA 5,000+ posts]

Ok I think I am going to make this simple. I think I am going to just use 2 HDC3.110 dual 1ohm in a ported box. I think I want about 1.5 net per sub, and will be pushing 800-1200rms to each.

man u good with diagrams., pretty lol.. i couldn't even draw that..

 

[Scotnemily]

man u good with diagrams., pretty lol.. i couldn't even draw that..

Lol thx. It is what I do for my day job. This was a super simple drawing though that took like 15 mins to model it up.

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[BOOMINGRANDPA 5,000+ posts]

Lol thx. It is what I do for my day job. This was a super simple drawing though that took like 15 mins to model it up.

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i wouldn't even know what program to use or how to use it.. just figured out firestick 8 months ago..

 

[Scotnemily]

I use creo 2.0 from PTC. Been doing it for 15 years...

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[Scotnemily]

Ok I mocked up another box. this one has a net really close to 3.0 CU FT. I am using 2 4" round ports at a length of 12" each. I think this gives me a tuning at 35hz. Can someone chime in on this? Any issues with this box for 2 HDC3.110 10"s running 800-1200rms each? Thanks!

Here it is with the subs thrown in.