Box design for 2 18" BTLs in Blazer

[Carnag3]

This is my second box and want to make sure the tuning is right before I built it.

I used sketchup and the tuning calculator pinned in this forum. Do my port measurements look ok? I don't have much experience in ported box design.

Any opinions and help appreciated

Heres the specs:

Box Height: 24

Box Width: 37.5

Box Depth: 34

Port Height: 6

Port Width: 25

Port Length: 34

Sub Displacement: .52

Gross airspace: 15.23 ft3

Port Volume: 3.32 ft3

Port Area: 150 in2

Net Airspace: 11.39

Tuning Frequency: 27.44

[Marlo Stanfield]

That's all on point, at least according to Expo's calc... Why are u planning on tuning so low?? It's kinda pointless to do so unless u only listen to like chopped + screwed type music. It will be completely lacking in any sort of authority prolli beyond 35-37hz or so. You can tune in the 33-35hz range and still kill the lows, while also being able to pick up the other bass notes in music.

[berniebp87]

That seems to be right, but I would raise the tuning a bit. As Marlo said, if you raise it to 33-37hz you will have a much versatile box musicwise. This looks alot like my previous box except my box was little bit smaller and had some kerfing done to it. Was tuned a bit low, 32-33hz and that killed the lowes. It played Decafs music like a motherf###er and also could handle some rock music pretty good so it was an allround great box. Raise your tuning up a bit and you will get a great box!

[Carnag3]

My main focus is on the lows, but I will definitely consider tuning it up at least to 30. Should the BTLs still pound the 28hz and under notes with this setup? And will it be safe to run the subsonic a little lower around 22 or will the subs unload?

[Boon]

If you run your subsonic at 22 you will still be getting a large amount of power down around 18hz. And then, yes, you will become well acquainted with the sound of your coil smashing into your backplate. Followed by the sound of a slinkied coil getting tangled up in a very tight gap.

Run your subsonic at your tuning frequency. It's not like a 100 percent cutoff, it's a slope...

[Carnag3]

So I'm thinking of narrowing the depth of the box to allow for a rear facing port... making the messurements 27 High, 37.5 wide, and 28 deep..this should give me about 6 inches of room between the port wall and the hatch. The only problem I'm having is getting the tuning I want with those dimensions. I would like a 29-30hz tunning, but in order to tune that low I either have to have a long port, while the box is only 28 deep, or make the port smaller which yields the low tuning BUT is brings the port area slightly under the recommended amount. Any suggestions? Is it possible to make two shorter ports to allow the low tuning and large port area? I have no clue how to go about calculating tuning with 2 ports.

[basslh]

http://www.stevemeadedesigns.com/board/ind...showtopic=63898 thats my build for my blazer check it out

[xtremeacoustiks]

I suggest a rear facing port tuned around 33hz and thats just from the 20 years experience I got...just my $.02

[basslh]

I suggest a rear facing port tuned around 33hz and thats just from the 20 years experience I got...just my $.02

yup if you wont the lows i would do the same mine is tuned to 35 and its good for all music and its the lows very nice