Demon 10" Enclosure Design Advice

[bumpinTL364]

Thanks for that work Joe, somehow didn't see it when I checked the other day. Never thought about a curved aeroport, I'm assuming that's acheived with PVC pipe?

 

I did do my due diligence before starting the initial build last year, but clearly, I didn't know what I didn't know. I confirmed on honda forums that the front speaker wires I tapped receive full signal, but I could probably give tuning the LC2i a shot as well (I got the fancy one that you can tune a point where the lc2i is supposed to fill in the subbass where the factory signal tends to roll off at higher volume levels).

 

I did try phase inverting the subs, sounded no different to me. I think I can conclude I'm either not getting the full range signal, I'm tuned too high due to small box volume, or I'm getting port noise that causes cancellation at low freqs. I'm playing around with some designs similar to the following thread at the moment. Any chance you can validate my design process since I'm at it?

 

1. Calculate max in-car volume available, go smaller if necessary for subwoofer mfg recommendation

2. use box volume and wattage to calculate port area required with triticum's port calculator

3. validate tuning with torres box calc, adjusting these three main parameters as necessary

 

The main issue I'm running into is not being able to fit the required port area in the box, besides the way you showed above

 

 

 

[Joe X]

1) OK so the turning port is made with a PVC elbow, pretty simple, no need to bend yourself or anything like that: https://canplas.com/plumbing/product_category/pvc-elbows/

 

2) yes you can try the bass restoration of the LOC but best is a proven full range signal, I would recommend to make sure this issue is fully resolved before starting to fix stuff elsewhere.

 

3) on that method, I would recommend using t/s parameters and modeling software to determine your port area, those calculators you find around are not based in physics and likely are a hit and miss, same goes for the 12-16 rule and I would only recommend those methods when no parameters for the sub are available and you don't have tools to obtain them.

 

Torres miscalculates port displacement, typically the predicted tuning is off by 1-2Hz, Torres is only fully accurate when you use a single round port and some non turning slot ports. Still if you don't cane about the 1-2 Hz remains a useful tool.

 

Lastly the way your box is made you can not calculate tuning correctly since it has two different port areas, the port area is much taller in the slanted section.

 

[bumpinTL364]

Thanks for that reply Joe, great info as always

 

With all that about the calculators being said, can you recommend one that's not too expensive? Given that I'll only use it a couple times a year, I don't want to pay an outrageous price, but I do want to do this correctly in the most professional/engineering way possible. 

 

Just a comment about my port design choice: I was under the impression that maintaining port area was the main concern, so the area of each smaller section sums to be the same as the large section. Now that I've had a couple courses in internet subwoofer things, as well as fluid dynamics, I can see the difference in velocity might also cause an issue.

 

Lastly, I did some more digging and found a way to completely flatten the factory EQ in my vehicle, through developer menus in the headunit. Sub 35hz bass has definitely improved, so I think my LC2i Pro was just being under-utilized. I presume I'll need to retune amp settings once I dial in the LC2i or find a way to keep the HU DSP flattened.

[Joe X]

For modeling I can recommend you bassbox pro, it's specifically designed with car audio in mind and it's easy to use, it's the very best you can get for the price, it even has a lite version that loses al lot of functionality but is like $65, it still gets some basic jobs done.