Subwoofer box design for JBL CS1215

[elango87]

Hi,

I am a newbie in boxdesigning.

I bought a JBL CS1215 couple of weeks back and planning to build a suitable box for the same to use it at home.

Below are the specifications of the sub:

Diameter: 12" (305 MM)
Sensitivity (2.83V@1M): 90dB
Power handling: 275W RMS 1100W PEAK
Freq response: 23 Hz - 450 Hz
Nominal Impedence: 4 ohms
Voice-Coil diameter: 2" (51 mm)

Outer diameter: 12-1/4"(311 mm)
Mounting depth: 6-1/16"(153 mm)
Cutout diameter: 11"(279 mm)

Thiele-Small Parameters:
Voice - coil DC resistence: R evc (OHMS) - 3.6
Voice - coil inductance @ 1kHz: L evc (mH) - 2.57
Driver Radiating Area: S D (IN^2) - 85.4
Driver Radiating Area: S D (M^2) - 551.00
Motor Force Factor: BL (TM) - 14.08
Compliance Volume: V AS (FT^3) - 2.7
Compliance Volume: V AS (LITERS) - 76.7
Suspension Compliance: C MS (microM/N) - 177.00
Moving Mass, Air load: M MS (GRAMS) - 179.00
Moving Mass, Diaphragm: M MD (GRAMS) - 171.00
Free-AIR Resonance: Fs (HZ) - 28.00
Mechanical Q: Q ms - 8.85
Electrical Q: Q es - 0.57
Total Q: Q ts - 0.54
Magnetic - GAP height: H ag (IN) - 0.307
Magnetic - GAP height: H ag (MM) - 7.8
Voice - Coil Height: H vc (IN) - 1.26
Voice - Coil Height: H vc (MM) - 32
Maximum Excursion: X MAX (IN) - 0.48
Maximum Excursion: X MAX (MM) - 12.1

Experts, please advice me on the dimensions.

I am planning to use MDF for box construction. Is it good for subwoofers?

Thanks,
Elango

 

[elango87]

http://www.stereoauto.it/manuali/jbl%20cs1214%20specifiche.pdf

The link above contains the specifications for CS1214 (Thiele parameters are same as that of CS1215).
I am planning to opt for Vented box. Page 2 of the PDF says that the Vbox should be 49.55 litres. I simply cannot understand the terms.

Can anyone tell me what should be the height, width and breadth of the box in inches ???

 

[bjorno]

http://www.stereoauto.it/manuali/jbl%20cs1214%20specifiche.pdf

The link above contains the specifications for CS1214 (Thiele parameters are same as that of CS1215).
I am planning to opt for Vented box. Page 2 of the PDF says that the Vbox should be 49.55 litres. I simply cannot understand the terms.

Can anyone tell me what should be the height, width and breadth of the box in inches ???

Hi elango87,

When Qts is larger than 0.5 you need to damp the entire box system
if the sub is to perform well and if the port is long you might run into pipe resonances.

Damed vent: The first of pictures:

Pipes:

http://documents.jordan-usa.com/Famous-Articles/Augspurger-Loudspeakers-on-Damped-Pipes.pdf

IMO better designs using the driver: The following pictures:

b🙂

 

[elango87]

@bjorno,

Thanks for the help. But the technical details you have provided are greek and latin to me. I couldnt understand anything :'(

It would be of great help if anyone help me by providing the exact length, width, height and the porting details.

Thanks in advance...

 

[bjorno]

..the technical details you have provided are greek and latin to me. I couldnt understand anything :'(...

Hi elango87,

😕 😱 Are you familiar with home-made Sanskrit-pixel drawings ?

Here is an attempt:

b🙂