Looking for insight into box/bracing design for 2.5-3 ft3 sealed subwoofer

[Vergiliusma]

Subs rarely needs bracing. Frequencies are too low to be a potential problem.

It's not about what frequencies the sub is producing, but the fact that the internal pressure, the energy can excite panel resonances, so bracing is about breaking them up by shifting them up higher in frequency and damping their overall output.

Someone mentioned the Thor subwoofer. It's net internal volume is around 1.75 cubic ft. and is corner braced. As the enclosure gets larger and displacement goes up, bracing is just good practice to have your bases covered.

Even commercial manufacturers use bracing. It increases cost and shipping weight, so they wouldn't do it if it wasn't necessary.

 

[Flaesh]

What do you mean

It seems very likely that a 1/2" offset will not be very "linear". You can test this in the real world. Both distortion and amplitude.

How do I take into account room transfer function>? Is that the same thing as room gain?

You can compare the anechoic response (calculated or measured in the near field) with the measured response at the listening position and the subwoofer at the subwoofer position. The difference between them is the function we are looking for. You can use any subwoofer or speaker for this. Sealed is more convenient.
Room gain is usually an essential component.

I am new and not familiar with everything.

Don't worry, everyone was a beginner once)

 

[HighFutility]

Update

The box is starting to take shape. I made the box out of 5/8 mdf instead of .75 inches. I thought it would be nice to be a bit lighter. BIG MISTAKE. Historically, most of my driver's mounting depth was about 10mm. This one was 20mm! I had to triple baffle the front because the depth is 20mm / .78 inches. This also provided a huge challenge for my router as I didn't have any router bits that went 1.89 inches deep—had to cut as deep as I could safely and then use a jigsaw.

From there, the driver didn't want to sit flush, most likely due to the precision of a novice using a jigsaw is not great. OD was perfect, but inner was not great. Spent two days sanding.

I should have just gone with a window brace, but I wanted to get a bit fancy and secure all panels with a cross brace. I was going to cut out the braces to be hollow but was so frustrated with the front baffle that I just called it a day.

I got the plate amp today, it is tiny! Will start working on the back to cut it out. Most likely using the jigsaw. Any tips for using a router instead to carve out the back to fit the plate amp?

 

[HighFutility]

It isn't pretty, but I'm just learning. Here are a few more updated photos. I had to make a jig out of MDF to flush mount the rear amp.

Box is basically done, sanding is all thats left. Filling in a few holes etc. Going to veneer the whole sub. Either walnut or something fun like zebra wood.