4th. order bandpass

[82 cutlass]

I'm thinking about doing a bandpass for 3 or 4 12's ported through the rear deck in my caddy . how's this graph look ? It's tuned to 55 hz.

Project for : you

--

Number of drivers : 3

Box type : 4th Order Bandpass

Box size : Front chamber 4.000 ft^3

Rear Chamber 3.000 ft^3

Tuning frequency : 55.00 Hz

Vent : 1 vent(s) -> Front Chamber

8.33 in length for each

14.00 x 5.00 in rectangle

Relative

Freq Gain SPL

[Hz] [dB] [dB]

20.00 -18.20 108.36

25.00 -12.83 113.73

30.00 -7.68 118.88

35.00 -2.56 124.00

40.00 1.81 128.37

45.00 3.36 129.92

50.00 2.66 129.23

55.00 1.74 128.30

60.00 1.10 127.67

65.00 0.70 127.26

70.00 0.38 126.94

75.00 0.02 126.58

80.00 -0.50 126.06

85.00 -1.23 125.33

90.00 -2.17 124.39

95.00 -3.27 123.30

100.00 -4.44 122.13

 

[RAM_Designs]

I'd adjust some stuff so you shift your f3 points down at least 5hz. Roughly 35-95hz is about 10hz too far up the response curve, in my opinion.

What program are you using?

 

[RAM_Designs]

I'd adjust some stuff so you shift your f3 points down at least 5hz. Roughly 35-95hz is about 10hz too far up the response curve, in my opinion.

What program are you using?

 

[82 cutlass]

I'd adjust some stuff so you shift your f3 points down at least 5hz. Roughly 35-95hz is about 10hz too far up the response curve, in my opinion.
What program are you using?

Ok thanks...I'm using winsd

 

[jake760]

Drop the tuning down to 45 or so, and give them some more port area. 70 inches for 3 12's in a 4th order isn't much... You could also make the ported side bigger if you have the space.

 

[pro-rabbit]

What will it be going in? Also what is the desired result? SPL or SQL? I agree with dropping the tuning and adjust the port area if you can.

 

[82 cutlass]

What will it be going in? Also what is the desired result? SPL or SQL? I agree with dropping the tuning and adjust the port area if you can.

It's going in a 92 cadillac brougham . Going to fire through the rear deck and seal it off from the trunk . I have a lot of space to work with so adjustments shouldn't be a problem with port and tuning . As for the result i'm looking for is just some loud daily SQL .

How's this look ? The box is 1 cube bigger in both the ported and sealed side tuned to 50 hz.

Project for : you

--

Number of drivers : 3

Box type : 4th Order Bandpass

Box size : Front chamber 5.000 ft^3

Rear Chamber 4.000 ft^3

Tuning frequency : 50.00 Hz

Vent : 1 vent(s) -> Front Chamber

11.99 in length for each

20.00 x 5.00 in rectangle

Relative

Freq Gain SPL

[Hz] [dB] [dB]

20.00 -15.97 110.59

25.00 -10.39 116.18

30.00 -5.03 121.53

35.00 -0.10 126.46

40.00 2.77 129.34

45.00 2.84 129.40

50.00 2.02 128.59

55.00 1.29 127.85

60.00 0.70 127.26

65.00 0.11 126.67

70.00 -0.60 125.96

75.00 -1.50 125.07

80.00 -2.58 123.99

85.00 -3.78 122.79

90.00 -5.03 121.53

95.00 -6.30 120.27

100.00 -7.53 119.04

 

[pro-rabbit]

That is looking a bit better, I typically like to see the db go down around 35hz area letting the roll off start their.......but most of my customers want to drop down and dig up the lows. Your setup there looks like it would be fine though roll off is not huge until after 30 so in car will be good deal lower.

 

[82 cutlass]

That is looking a bit better, I typically like to see the db go down around 35hz area letting the roll off start their.......but most of my customers want to drop down and dig up the lows. Your setup there looks like it would be fine though roll off is not huge until after 30 so in car will be good deal lower.

Cool...thanks . I'll post some pics of the build...whenever i get to it lol

 

[82 cutlass]

I came up with this for 4 12's . It's 11 cubes I don't want to go any bigger . I want to save some room for the air ride stuff . If i do 4 12's it's going to be a 3 chamber bandpass . Should I separate each woofer in it's own box or will 2 sharing the same side be ok ? This is my first multiple sub bandpass...wanna make sure i do it right .

Number of drivers : 4

Box type : 4th Order Bandpass

Box size : Front chamber 6.000 ft^3

Rear Chamber 5.000 ft^3

Tuning frequency : 50.00 Hz

Vent : 1 vent(s) -> Front Chamber

10.52 in length for each

24.00 x 5.00 in rectangle

Relative

Freq Gain SPL

[Hz] [dB] [dB]

20.00 -16.28 112.50

25.00 -10.61 118.17

30.00 -5.11 123.67

35.00 -0.09 128.70

40.00 2.45 131.23

45.00 2.07 130.85

50.00 1.11 129.89

55.00 0.38 129.16

60.00 -0.13 128.65

65.00 -0.57 128.21

70.00 -1.09 127.70

75.00 -1.77 127.01

80.00 -2.66 126.12

85.00 -3.71 125.07

90.00 -4.88 123.91

95.00 -6.08 122.70

100.00 -7.29 121.50

 

[82 cutlass]

Ok i have been thinking about going with 2 15's and the boxes seem small.

Number of drivers : 2

Box type : 4th Order Bandpass

Box size : Front chamber 3.500 ft^3

Rear Chamber 3.000 ft^3

Tuning frequency : 50.00 Hz

Vent : 1 vent(s) -> Front Chamber

19.49 in length for each

15.00 x 6.00 in rectangle

Relative

Freq Gain SPL

[Hz] [dB] [dB]

20.00 -13.58 113.43

25.00 -7.55 119.46

30.00 -1.78 125.23

35.00 2.40 129.41

40.00 3.11 130.12

45.00 2.43 129.44

50.00 1.96 128.97

55.00 1.86 128.87

60.00 1.99 129.00

65.00 2.10 129.11

70.00 1.92 128.93

75.00 1.21 128.22

80.00 -0.01 127.00

85.00 -1.53 125.48

90.00 -3.15 123.86

95.00 -4.73 122.28

100.00 -6.24 120.77

What do you guy's think ?

 

[80INCHES]

ok ur sealed chamber is too big for the 3 or 4 12s

make ur sealed chamber 2.4 cubes and ur ported chamber 6 cubes with a 120 square inch port tuned to 47hz

80

 

[82 cutlass]

ok ur sealed chamber is too big for the 3 or 4 12smake ur sealed chamber 2.4 cubes and ur ported chamber 6 cubes with a 120 square inch port tuned to 47hz

80

Cool thanks...I'm still deciding on either 3 or 4 12's...or 2 15's . I have about 14 cubes total that i can use and still have room for amps...batterys and maybe air ride stuff . That's for the 3 12's right ?

 

[galacticmonkey]

Go 1 cube sealed, 1.25 ported, 25in^ of port at 47hz per sub. If you were doing 4 12s, it would be 4 sealed, 5 ported, with 100in^ of port for example.

 

[82 cutlass]

Go 1 cube sealed, 1.25 ported, 25in^ of port at 47hz per sub. If you were doing 4 12s, it would be 4 sealed, 5 ported, with 100in^ of port for example.

That's not too bad for 4 12's...I can fit that .

Thanks !!