![](https://blog.julienarnaud.fr/media/website/dsc_0069.jpg)
Re-enclosed JBL SB210 Subwoofer
Unsatisfied with my JBL SB210 low frequency, I designed and built replacement enclosures.
![](https://blog.julienarnaud.fr/media/posts/16/jbl_sb_210_1.jpg)
The SB210 is a dual 210mm subwoofer, using ceramic cones in a polymer enclosure.
Specifications of JBL's original SB210 are
- 48Hz (-3dB)
- 42Hz (-10dB)
My redesigned enclosure offers
- 29Hz (-3dB)
- 16Hz (-10dB)
![](https://blog.julienarnaud.fr/media/posts/16/Screenshot-from-2024-06-04-23-27-09.png)
The first hurdle was the absence of datasheet for the speakers themselves, as they were never distributed outside of the SB210 system.
![](https://blog.julienarnaud.fr/media/posts/16/fullsizeoutput_565.jpeg)
After contacting JBL Professional, they were kind enough to provide me with the data.
- Fs : 25.38 Hz
- VAS : 73L
- Re : 3.32 Ohms
- Qms : 3.31
- Qes : 0.470
- Sd : 340.00 cm2
![](https://blog.julienarnaud.fr/media/posts/16/img_1674.jpg)
These specifications were entered in Dominique Petoin's database and you can now find it there. As I was trying to reach lower frequencies, the bass-reflex architecture was the obvious choice.
![](https://blog.julienarnaud.fr/media/posts/16/Screenshot-from-2024-06-07-21-43-40.png)
Multiple tuning were possible, and I chose to go with the Bessel alignement which offered a gentle dropoff curve.
![](https://blog.julienarnaud.fr/media/posts/16/Screenshot-from-2024-06-07-21-46-57.png)
The simulation gave
- @92 dB ±2.13 mm of membrane travel
- 103.0 dB @1m for a single subwoofer (but I built two)
![](https://blog.julienarnaud.fr/media/posts/16/Screenshot-from-2024-06-07-21-51-49.png)
![](https://blog.julienarnaud.fr/media/posts/16/Screenshot-from-2024-06-07-21-52-18.png)
![](https://blog.julienarnaud.fr/media/posts/16/graph_br_db.png)
Enclosure specifications
- Volume : 65.4L (net), 70.82L (raw)
- Reinforcement : 164cm (5x5cm)
- Volume renforts : 4.1L
- Frequency tuning : 19.9Hz
- Bass-reflex vent : ø 9.4cm (in), ø 10cm (out), 72cm (length)
- Top/Bottom : width 33.4 cm x depth 38.4 cm
- Front/Rear : width 33.4 cm x height 76.5 cm
- Sides : depth 34.0 cm x height 76.5 cm
I used 38mm thick MDF, as it is a very "deaf" material, fairly inexpensive and extremely sturdy in this thickness.
![](https://blog.julienarnaud.fr/media/posts/16/img_9222.jpg)
I didn't have speakon terminals so I went with a ghetto solution in the meantime.
![](https://blog.julienarnaud.fr/media/posts/16/img_4336.jpg)
Notice how the vent is glued with Polyuerthane to the structure as to avoid any parasitic noises.
![](https://blog.julienarnaud.fr/media/posts/16/img_4341.jpg)
Listening & Conclusion
I can't stress how much I love those subwoofers. They are ungodly and extremely heavy but the sound... They go as low as you might ever want a sub to go, and are able to keep up with high powers. Not the slightest resonance or airflow sound can be heard.
At the time, I actualy discovered a spectrum of bass I didn't know even existed in some tracks. Quality headphone can reproduce down to 20Hz, but I would say that the 20 to 40Hz range needs to be felt with actual speakers.
Currently they are in the house, fed by a Crown CT8150 with active filtering using the MiniDSP 10x10 HD. They are filtered to reproduce anything below 50Hz.
![](https://blog.julienarnaud.fr/media/posts/16/img_9257.jpg)