B2 Audio 35949
Best box: 1.9 L bass reflex tuned to 57.4 Hz · F3 51.6 Hz
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Comparable 2.0" Drivers
Drivers with similar piston area, resonance and Qts — useful alternatives when the B2 Audio 35949 does not fit your target box volume or tuning. Each entry links to its full enclosure design and Thiele/Small parameters.
⚠️ Engineering Notice for Builders
- The textbook alignment (1.5 L at 82.0 Hz) would need a 54.8 cm port; the recommendation is retuned to 1.9 L at 57.4 Hz so the port can be built.
- Xmax is not published, so the port size is an empirical estimate (area ≥ 12 in² per ft³ of net volume, minimum by driver size), not a displacement calculation. Check air velocity in Load Forge Studio.
- Port length (90.4 cm) exceeds a straight internal run; use an elbow bend, slotted vent or 3D folded duct to fit the enclosure.
Recommended Bass Reflex (Vented)
PORT NEEDS ELBOW / 3D| Net Box Volume (Vb) | 1.9 Liters |
| Tuning Frequency (Fb) | 57.4 Hz |
| F3 (-3 dB Cutoff) | 51.6 Hz |
| F6 / F10 Extension | 49.4 Hz / 46.7 Hz |
| Port Inner Diameter ESTIMATED | Ø 5.0 cm |
| Port Physical Length | 90.4 cm |
| First Pipe Resonance | 190.0 Hz |
| Estimated MOL @ F3 | 95.0 dB SPL |
Sealed (Acoustic Suspension) — compromise
SUITS INFINITE / OPEN BAFFLEWith Qts 1.1 a Butterworth (Qtc 0.707) box would be many times Vas. A box equal to Vas reaches Qtc 1.556; for a flat response this driver is better used on an infinite (IB) or open baffle.
| Net Box Volume (Vb) | 0.2 Liters |
| System Q (Qtc) | 1.556 (above Butterworth: Qtc cannot fall below Qts (1.10)) |
| System Resonance (Fc) | 136.5 Hz |
| F3 (-3 dB Cutoff) | 113.3 Hz |
| F6 / F10 Extension | 98.2 Hz / 82.0 Hz |
| Air Spring Linearity | High (Zero port compression) |
Thiele/Small Parameters
| Resonance (Fs) | 96.5 Hz |
| Total Q (Qts) | 1.1 |
| Electrical Q (Qes) | 1.428 |
| Mechanical Q (Qms) | 4.79 |
| Equivalent Volume (Vas) | 0.2 Liters |
| Diaphragm Area (Sd) | 15.2 cm² |
| DC Resistance (Re) | 3.59 Ω |
| Efficiency Bandwidth Product (EBP) | 67.6 |
| Linear Excursion (Xmax) | N/A mm |
| Thermal Power (Pe) | 100.0 W |
| Nominal Diameter | 2.0" |
| Catalog Source | Load Forge catalog (manufacturer datasheets and retailer listings) |
Frequently Asked Questions
What is the recommended ported (bass reflex) box volume for B2 Audio 35949?
Load Forge's calculated alignment puts B2 Audio 35949 in a 1.9 liter vented enclosure tuned to 57.4 Hz, reaching an F3 cutoff of approximately 51.6 Hz.
Can B2 Audio 35949 be used in a sealed box?
Yes. In a sealed (acoustic suspension) enclosure of 0.2 liters with a Qtc of 1.556 (above Butterworth: Qtc cannot fall below Qts (1.10)), the system exhibits an F3 of 113.3 Hz.
What port dimensions should be used for B2 Audio 35949 to avoid port chuffing?
Xmax is not published for B2 Audio 35949, so the port is an empirical estimate: a 5.0 cm diameter with a length of 90.4 cm (area at least 12 in² per ft³ of net volume). Check the air velocity at your power level in Load Forge Studio.
Shareable Acoustic Card for Forums & Social Media
Embed this design card on DIYAudio, AVSForum, Reddit, or Facebook. It shows the calculated F3, MOL (when the power rating is published) and box parameters.
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