Box questions

[Holcomb]

I currently have a 3.6 cubic box with 3inch square ports that are 12" long and the box is made out of particle board.

How big of a difference will the 4.07 cube, mdf, tuned to 31hz box be? It's being built as we speak

Difference in air movement? If so, how much as a guesstimate?

Difference in flex? If so, how much as a guesstimate?

[Neckbeard]

MDF over particle board any day of the week

MDF is more dense, meaning less box flex and the sound is gonna bounce off of it and go out of the port better.

[FeelDaBass]

What was the tuning of the other box?

Were the port(s) 3x3 inches? And how many ports were there?

Also, is this box in the same location facing the same way and everything?

[Holcomb]

The ports were 3x3. And I don't know the tuning honestly. There were 2 chambers, each with 1 3x3 port. Yes the box is in the same location, facing the same way.

[FeelDaBass]

According to the 12volt website, that was about a 30.5 hz tuning.

I'm not an expert, but I'm pretty sure the larger box with MDF will be louder. You didn't say how big the port is going to be, but should definitely sound different.

[Holcomb]

Not sure about the exact dimensions of the new port because I told the shop to get ahold of RF hq and work it out to tune it to 31 and sound great on decaf. I don thing the old box is tuned to 30.5, but it does get down.

[321slapinbass]

the first thing that I see wrong is the size of the ports. with the old box you had 5 in^2 of port per cube which is WAY to small. you want to stay between 12in^2 - 16in^2 for proper ventilation. a larger port will also be louder in your case since yours were to small. I really hope the port/ ports on the new box are much bigger.

[321slapinbass]

wrong, you didn't subtract the displacement of the ports. if he used 3/4" wood then each port has a displacement of .13 cubes making each chamber 1.67 cubes tuned to 31.6hz. and if he used 1/2" wood then each port has a displacement of .07 cubes making each chamber 1.73 cubes tuned to 31.1hz. a lot of people forget this and that's why their boxes are tuned wrong.

According to the 12volt website, that was about a 30.5 hz tuning.

I'm not an expert, but I'm pretty sure the larger box with MDF will be louder. You didn't say how big the port is going to be, but should definitely sound different.

[FeelDaBass]

I assumed that was an internal measurement...so there ya go. It's close anyway...it was just to make sure it wasn't at, let's say 40hz...which I'm sure you know would be completely different...

[FeelDaBass]

I didn't even try the port ratio though...good observation on that part. With a 4.07 cu ft INTERNAL volume(after displacements), you're going to want about a 57^2 inch port with a 33 inch long port. But since someone else is making it, I'm sure if they are decent, they'll get you some good results.