Double Checking My Design

[DLHgn]

Hey guys, I was just wondering if I did everything correctly on my design. This isn't really something I plan on building due to not knowing the exact dimensions of my available space but it is a rough estimate to help my design process to move along. According to my calculations and messing with WinIsd the Net volume after bracing and sub displacement should be 11.15 ft3 and my port tuning should be ~24Hz. I know it's tuned pretty low but I like low and the Fs of the subs I want to use are ~28.9 and drops a few Hz after being broken in.

The subs that this box is designed for are the B2 IS15v3: http://www.b2audio.com/is

These would be run between 2000 - 3000 W RMS

If someone could just double check my design, I would be grateful. Thank you in advance.

[Triticum Agricolam]

I would add significantly more bracing. Those are big panels and you are going to be putting decent power into this system.

Here are the general guidelines I try to follow when designing bracing:

1. Keep unbraced spans appropriate for material used. (Under 10"-12" for 3/4" MDF/Plywood)

2. Brace across to opposite panels when possible, otherwise brace to adjoining panel.

3. Minimize bracing in corners where it is unneeded.

4. Take up the least amount of internal volume as possible.

5. Minimize disruptive bracing in high airflow areas.

[DLHgn]

So would you suggest replacing the current brace with something else or supplementing it with other bracing?

[Triticum Agricolam]

I would change your current brace and add additional bracing. The piece on your current brace running from corner to corner isn't doing much. Boxes aren't stressed in that dimension. You want your cross piece running from front to back.

[DLHgn]

What do you mean? The brace hits all sides

[Triticum Agricolam]

Piece "A" doesn't really add any strength, since the box isn't stressed along that dimension. What you are trying to do is stop the front and back panels from flexing, so you need to link them together, as indicated with pieces "B".

I would also add additional braces between the front and back panels right above and below the driver cutouts. These could be dowels or stips of MDF/plywood. Either will work.

[DLHgn]

Oh ok, that makes sense now. You know...thank you for your help. Everytime I talk to you I learn something new and useful. I really appreciate it. How does my port look? Is it enough port area? I tried making it as large as I could to help with the port noise

[Triticum Agricolam]

Sorry, I didn't even really look at your port dimensions until now.

With 63.75 sq in, your port is on the small side and you are going to have higher port velocity than I would like to see assuming 3,000 watts of input power. However, with your low tuning, the frequency that the port velocity peaks at is so low (like 22 Hz) it probably won't matter.

So, you could leave it how it is and you shouldn't have any port issues unless you play a lot of stuff below 30 Hz. If you wanted to make it bigger, it wouldn't hurt, or if you ever think you will tune higher, then you should definitely increase port area.

[DLHgn]

I'll mess with it and see if I can make it larger without making it too huge. What area should I be shooting for in this case? ~100?

[Triticum Agricolam]

Yeah a 100 sq in would be a good number.