Installing a new sub

[falkenbd]

I'm installing a TW-12 for someone. Do these two options seem reasonable?

This is what I got out of WinISD after playing around for ported:

Not sure if I can fit 18" of port in the box tho

Driver : Massive TW12

Number of drivers : 1
Box type : Vented
Box size : 2.000 ft^3
Tuning frequency : 28.05 Hz
Vent : 1 vent(s)
18.37 in length for each
4.02 in round


Relative
Freq Gain
[Hz] [dB]
20.00 -11.41
25.00 -5.12
30.00 -2.32
35.00 -0.97
40.00 -0.23
45.00 0.20
50.00 0.43
55.00 0.54
60.00 0.58
65.00 0.59
70.00 0.57
75.00 0.54
80.00 0.51
85.00 0.48
90.00 0.44
95.00 0.41
100.00 0.38
105.00 0.36
110.00 0.33
115.00 0.31
120.00 0.29


Here is a sealed box:

umber of drivers : 1
Box type : Closed
Box size : 1.590 ft^3


Relative
Freq Gain
[Hz] [dB]
20.00 -14.89
25.00 -11.21
30.00 -8.38
35.00 -6.21
40.00 -4.56
45.00 -3.34
50.00 -2.45
55.00 -1.81
60.00 -1.35
65.00 -1.02
70.00 -0.77
75.00 -0.60
80.00 -0.47
85.00 -0.37
90.00 -0.30
95.00 -0.24
100.00 -0.19
105.00 -0.16
110.00 -0.13
115.00 -0.11
120.00 -0.09


I'm leaning more towards the sealed just for ease of building, and it doesn't look to be a huge different in output between the 2.

[Ryan from Ohio]

My spidey sense says 28.05 Hz is to low. Try 32 or 34.

[cargodz]

^I can tell you the TW will love 32-34Hz

[MobileAudio219]

^I can tell you the TW will love 32-34Hz

Yeah, well I'm going to say 2.25 cuft tuned to 35hz...

NOTE: I have no clue, but it sounds good, right?

[Ryan from Ohio]

lol, I would lean more towards 32 Hz depending on the Fs of the sub.

[MobileAudio219]

I trust your opinion ryan, but it sounds more techincal if you throw in an extra 1/10th or so here and there...

so yeah, I would go with:

2.02 cuft turned to 32.04hz

Sure, there isnt going to be an audioable difference, but it makes people think, dont it??? Yeah.... See there?

[falkenbd]

I might be trying to go with this Driver : Massive TW12
Number of drivers : 1
Box type : Vented
Box size : 2.272 ft^3
Tuning frequency : 35.00 Hz
Vent : 1 vent(s)
27.05 in length for each
12.50 x 2.75 in rectangle


Relative
Freq Gain
[Hz] [dB]
20.00 -17.25
25.00 -9.17
30.00 -2.97
35.00 1.00
40.00 2.59
45.00 2.80
50.00 2.56
55.00 2.24
60.00 1.95
65.00 1.69
70.00 1.48
75.00 1.30
80.00 1.15
85.00 1.02
90.00 0.92
95.00 0.83
100.00 0.75


I have a question tho. When I'm drawing up the box, I need to come up with the 2.25 square feet plus the volume of the port which is roughly .538 plus the volume of the wood used to create the port and any internal bracing? (lets say .2 cubic feet)

So the gross volume of the box should be about 3 cubic feet? 2.25+0.538+0.2 ?

You think a 12.50 x 2.75 rectangle port 27.05 in length is decent?

I'm thinking the box will be 14" wide 12.5 would be the width between the side walls, which is why I used that as port width. Sub and port on the same face, port would probably have a turn in it.

I'm going to see if I can draw it in sketch up later.

[falkenbd]

bumping because MobileAudio219 posted on every other thread and knocked this off the front page :)

[scotts1000rr]

^^^^^^^lol he was taking up the whole page

[Ryan from Ohio]

Thats about 35 Sq In of port area, should be plenty.

What you need to add up is the volume of the box (inside), volume of the port, then add the volume of a brace if you add one and the volume of the 1 or 2 walls of the port.

Remember your port needs to be 2.75" across the back also and you measure the length by the center of the port, not the sides.

Easiest way Ive found to do it is this. Once you have your port figured that gives you the height you need. Then figure the port out rest of the way. For instance your 12.50" X 2.75" port's first leg is 12", the connector 3.25 (port width + .75 for material) then the last leg would be 11.50". Obviously that wouldnt work as you should leave at least 2.75" from front of box IF brining the port to the front. Or you can run the port against the back wall. Hoever you choose. Then you will have an area behind the port which that volume is added onto the box overall.

Then use the simple formula of 12X12X12=1728 to your advantage.