Cinema Subwoofer

[JacoLouw]

Hey guys!

I would like to use my old car subwoofers for building a solution for my home cinema. I have made a few box designs and ended up with two. The only difference between the two designs are the port lengths. They are both simple rectangular shape and I would like to put the port on the same front facing panel as the subs. Unfortunately the longer port doesn't fit on front and would have to go on the top.
I am looking for a more "high fidelity", smooth response rather than a boom box.
Please let me know what you think about the box design specs and which one would work better, or if you would do it different all together.

The room is about 30-35m3 big and is sound treated. I am planning on running this amp on it in a 4ohm load:
Dayton Audio SA1000 Subwoofer Amplifier Rack Mountable


Thank you!
Jaco

Design 1: (long port)

Driver Properties
Name: RFR2215
Type: Standard one-way driver
Company: Rockford Fosgate Corp.
Comment: Power DVC series
No. of Drivers = 2
Mounting = Standard
Wiring = Parallel
Dual voice coils = parallel
Fs = 20 Hz
Qms = 5.97
Vas = 260 liters
Xmax = 13.5 mm
Sd = 860 sq.cm
Qes = 0.38
Re = 1.8 ohms
Le = 2 mH
Z = 2 ohms
Pe = 600 watts
-----------------------------------------
Box Properties
Name:
Type: Vented Box
Shape: Prism, square
Vb = 227.9 liters
Fb = 20.37 Hz
QL = 5.193
F3 = 35.11 Hz
Fill = none
No. of Vents = 1
Vent shape = round
Vent ends = two flared
Dv = 135 mm
Lv = 382.5 mm

Design 2: (short port)
Driver Properties
Name: RFR2215
Type: Standard one-way driver
Company: Rockford Fosgate Corp.
Comment: Power DVC series
No. of Drivers = 2
Mounting = Standard
Wiring = Parallel
Dual voice coils = parallel
Fs = 20 Hz
Qms = 5.97
Vas = 260 liters
Xmax = 13.5 mm
Sd = 860 sq.cm
Qes = 0.38
Re = 1.8 ohms
Le = 2 mH
Z = 2 ohms
Pe = 600 watts
-----------------------------------------
Box Properties
Name:
Type: Vented Box
Shape: Prism, square
Vb = 229.3 liters
Fb = 22.39 Hz
QL = 5.193
F3 = 34.54 Hz
Fill = none
No. of Vents = 1
Vent shape = round
Vent ends = two flared
Dv = 135 mm
Lv = 295 mm

 

[paulys55]

"Wiring = Parallel
Dual voice coils = parallel"...

Maybe I'm reading this wrong but if you wire the VC in parallel and the two subs in parallel you will see a 2ohm load which I don't think that amp will like...maybe I read it wrong.

 

[JacoLouw]

"Wiring = Parallel
Dual voice coils = parallel"...

Maybe I'm reading this wrong but if you wire the VC in parallel and the two subs in parallel you will see a 2ohm load which I don't think that amp will like...maybe I read it wrong.

You right, missed that! Thanks!

Here's the new result (same box size with shorter port):

Driver Properties
Name: RFR2215
Type: Standard one-way driver
Company: Rockford Fosgate Corp.
Comment: Power DVC series
No. of Drivers = 2
Mounting = Standard
Wiring = Parallel
Dual voice coils = series
Fs = 20 Hz
Qms = 5.97
Vas = 260 liters
Xmax = 13.5 mm
Sd = 860 sq.cm
Re = 7.2 ohms
Z = 8 ohms
-----------------------------------------
Box Properties
Name:
Type: Vented Box
Shape: Prism, square
Vb = 229.3 liters
Fb = 22.39 Hz
QL = 5.047
F3 = 33.28 Hz
Fill = none
No. of Vents = 1
Vent shape = round
Vent ends = two flared
Dv = 135 mm
Lv = 295 mm

What are your thoughts?

 

[richie00boy]

To your ears there won't be much difference.
Can't you use an elbow joint to put a bend in the port so you can use the longer length? Or change you height/width/depth ratio to achieve the necessary depth?

 

[JacoLouw]

"Wiring = Parallel
Dual voice coils = parallel"...

Maybe I'm reading this wrong but if you wire the VC in parallel and the two subs in parallel you will see a 2ohm load which I don't think that amp will like...maybe I read it wrong.

You right, missed that! Thanks!

Here's the new result (same box size with shorter port):

Driver Properties
Name: RFR2215
Type: Standard one-way driver
Company: Rockford Fosgate Corp.
Comment: Power DVC series
No. of Drivers = 2
Mounting = Standard
Wiring = Parallel
Dual voice coils = series
Fs = 20 Hz
Qms = 5.97
Vas = 260 liters
Xmax = 13.5 mm
Sd = 860 sq.cm
Re = 7.2 ohms
Z = 8 ohms
-----------------------------------------
Box Properties
Name:
Type: Vented Box
Shape: Prism, square
Vb = 229.3 liters
Fb = 22.39 Hz
QL = 5.047
F3 = 33.28 Hz
Fill = none
No. of Vents = 1
Vent shape = round
Vent ends = two flared
Dv = 135 mm
Lv = 295 mm

What are your thoughts?

 

[JacoLouw]

To your ears there won't be much difference.
Can't you use an elbow joint to put a bend in the port so you can use the longer length? Or change you height/width/depth ratio to achieve the necessary depth?

I was also considering an elbow joint until I read how many people are against it. "Air doesn't like to be forced around bends".

What are your thoughts on the fs and f3 of the short port box on these particular subs?

 

[Etocynned]

An elbow joint shouldnt pose too much problem. Its a nice radiused bend.

What is particle velocity at tuning?

 

[Bern Wansen]

You have jice subs, they are very robust as per its parameters. A ported box will behave like a boom box almost always at these frequencies/ port sizes, mainly considering the box size I think it wont even have any advantage on using ports.
Really, I made an oversized box once and it has not benefit. The box will radiante more sound through its faces than the sub itself lol

 

[Moondog55]

Given the driver parametres I would consider a smaller sealed box myself